tag:blogger.com,1999:blog-48021277550443683202024-03-04T20:33:56.394-08:00Electronics Circuit ApplicationThis Blog show the Different Electronics Circuit Design, Application, Fields and Resources which could help students, engineers, professionals, and common people whose interest is in electronics!!!Unknownnoreply@blogger.comBlogger116125tag:blogger.com,1999:blog-4802127755044368320.post-19645737545910751012009-06-13T20:20:00.000-07:002009-07-08T08:39:49.680-07:00LOW-COST HEARING AIDCommercially available hearing aids are quite costly. Here is an inexpensive hearing aid circuit that uses just four transistors and a few passive components. On moving power switch S to ‘on’ position, the condenser microphone detects the sound signal, which is amplified by transistors T1 and T2. Now the amplified signal passes through coupling capacitor C3 to the base of transistor T3. The signal is further amplified by pnp transistor T4 to drive a low impedance earphone. bg8j9xp2ym<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNVk9mGqEnuTGva1054LwWa6ZYMSIFnunoRRoR1Rq3iPmSov-GMSp0457dNbZqadjJXN5SK3cWeSrHXoh7X9FN4vs2RllzyRU6W9XFexGMQz_F_-wSE2AFoBK7jSez2Pomem59D463kaDf/s1600-h/12.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 222px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNVk9mGqEnuTGva1054LwWa6ZYMSIFnunoRRoR1Rq3iPmSov-GMSp0457dNbZqadjJXN5SK3cWeSrHXoh7X9FN4vs2RllzyRU6W9XFexGMQz_F_-wSE2AFoBK7jSez2Pomem59D463kaDf/s400/12.jpg" alt="" id="BLOGGER_PHOTO_ID_5346706798223568690" border="0" /></a><span class="fullpost"><br />Capacitors C4 and C5 are the power supply decoupling capacitors. The circuit can be easily assembled on a small, general-purpose PCB or a Vero board. It operates off a 3V DC supply. For this, you may use two small 1.5V cells. Keep switch S to ‘off’ state when the circuit is not in use. To increase the sensitivity of the condenser microphone, house it inside a small tube. This circuit costs around Rs 65.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-25363717052274357212009-06-12T20:42:00.000-07:002009-06-12T20:53:45.863-07:00Magnetic Levitation<span style="font-weight: bold;">How Levitation Works</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3gSHaymv0uHiTZIT-vyCCe28ZtPHuQuF4sROgi5TVPz31ahxIp3KwCNmlZF6ds6esKxTm3a9JDNw7IKO6_jYktYlOpWGpZ9AmRxDorCg5V4YT-ySta1jNtAG0tdq3bFPCFIoMoM9pSNme/s1600-h/3.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3gSHaymv0uHiTZIT-vyCCe28ZtPHuQuF4sROgi5TVPz31ahxIp3KwCNmlZF6ds6esKxTm3a9JDNw7IKO6_jYktYlOpWGpZ9AmRxDorCg5V4YT-ySta1jNtAG0tdq3bFPCFIoMoM9pSNme/s400/3.jpg" alt="" id="BLOGGER_PHOTO_ID_5346654859833834210" border="0" /></a><br />If you hold two permanent magnets close together, you see that one of them will jump strongly toward (or away) from the other. In 1842, Samuel Earnshaw expressed the perversity of inanimate magnetic objects in his theorem. It explains this frustrating behavior will always prevent you from suspending one permanent magnet above or below another, no matter how one arranges the two magnets. However, an active control circuit can get around this problem by rapidly adjusting the magnet's strength.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRZ8bIt_Jczct1Dst1EYKNwv9a9Dyb7eDDeNgj70Id_K0dwRyazm0MrP-f2arCWy3LTzoG1q6CtIwGzFIYHGH7VUZt52qLhQe5gE5Y8pJbhUrsPLYzDN9yfJY0FUFrnNn1FQIpxxgtdvCq/s1600-h/2.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 346px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRZ8bIt_Jczct1Dst1EYKNwv9a9Dyb7eDDeNgj70Id_K0dwRyazm0MrP-f2arCWy3LTzoG1q6CtIwGzFIYHGH7VUZt52qLhQe5gE5Y8pJbhUrsPLYzDN9yfJY0FUFrnNn1FQIpxxgtdvCq/s400/2.jpg" alt="" id="BLOGGER_PHOTO_ID_5346654860384099010" border="0" /></a><br />Click this image to see closeup of antigravity relay (38K) The general principle is straight forward: An electromagnet pulls a ball upward while a light beam measures the exact position of the ball's top edge. The magnet's lifting force is adjusted according to position.<span class="fullpost"><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL5_TuXQgRVGdGnrx3sgCyljyUNk8wdFAAZhzVCZlaPDd_bB3ieVE_IF1tEVgsDHtzzPEiR9lKItfEuv67n_EQiJI8PZjAF1gkme2AmTEkWdg-tgyCFkRxrqtJ7qgGa7ZepW74N-GGYVCH/s1600-h/4.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL5_TuXQgRVGdGnrx3sgCyljyUNk8wdFAAZhzVCZlaPDd_bB3ieVE_IF1tEVgsDHtzzPEiR9lKItfEuv67n_EQiJI8PZjAF1gkme2AmTEkWdg-tgyCFkRxrqtJ7qgGa7ZepW74N-GGYVCH/s400/4.jpg" alt="" id="BLOGGER_PHOTO_ID_5346654864660275650" border="0" /></a><br />As less light is detected, the circuit reduces the electromagnet's current. With less current, the lifting effect is weaker and the ball can move downward until the light beam is less blocked. Voila! The ball stays centered on the detector! It is a small distance across the photodetector, perhaps a millimeter or two, but this is sufficient to measure small changes in position. Of course, if the ball is removed the coil runs at full power. And conversely, if the light beam is blocked the coil is turned completely off.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgugpXI4r8Dn9OmAwSFme7kJuGnS04T0nqH89FU2vws-hj4o-kehtoHVxXjkVKyULsUkKmx4jwe5AS_K_1WdsbeNhQjDo388g-qpvK8rY19qTabvDMWvh5nn5un_W6nDh_Y4g0522bbemm1/s1600-h/1.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 208px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgugpXI4r8Dn9OmAwSFme7kJuGnS04T0nqH89FU2vws-hj4o-kehtoHVxXjkVKyULsUkKmx4jwe5AS_K_1WdsbeNhQjDo388g-qpvK8rY19qTabvDMWvh5nn5un_W6nDh_Y4g0522bbemm1/s400/1.jpg" alt="" id="BLOGGER_PHOTO_ID_5346654854379314162" border="0" /></a><br /><br />Click here to see image of breadboard circuit (54K) This device uses two photodetectors: the "signal" detector looks for an interruption in the light beam, and the "reference" detector measures the background light. The circuit subtracts one signal from the other to determine the ball's position. The use of two detectors is my small contribution to advance the art of levitation. This design automatically compensates for changes in ambient light, and eliminates a manually<br /><br /><span style="font-weight: bold;">Magnetic Levitation Parts List</span><br /><br /><span style="font-weight: bold;">Resistors</span><br /><br />Resistors listed in order by value are 1/4-watt, 5% unless otherwise indicated.<br /><ul><li>300 ohms R11</li><li>500 ohms R2</li><li>1,000 ohms R1, R12, R13, R14 </li><li>1,500 ohms R10</li><li>10,000 ohms R4</li><li>11,000 ohms R6</li><li>22,000 ohms R8</li><li>56,000 ohms R3</li><li>100,000 ohms R5</li><li>150,000 ohms R7</li><li>370,000 ohms R9</li><li>50K linear taper VR1 (and VR2 opt.)</li></ul><span style="font-weight: bold;">Capacitors</span><br /><ul><li>C1,C2 47 uF electrolytic</li><li>C3 0.1 uF ceramic or tantalum (must not be electrolytic)</li></ul><span style="font-weight: bold;">Semiconductors</span><br /><ul><li>Q1,Q2 OP505A infrared photo detector, or equivalent</li><li>Q3 2N3055 NPN power transistor</li><li>LED1,2,4 Red light-emitting diode</li><li>LED 3 Infrared LED emitter</li><li>IC1-4 LM741 op amp, Radio Shack 276-007</li><li>D1 1N4001 (or 1N4004) silicon diode, 50v (or more) peak inverse voltage</li></ul><span style="font-weight: bold;">Miscellaneous</span><br /><br /><ul><li>+/- 15 vdc power supply, 1 amp</li><li>9 vdc power supply, 1 amp</li><li>Breadboard wiring pad (or printed circuit board by Amadeus)</li><li>18-ga stranded wire for power</li><li>Solid hook-up wire</li><li>24-ga (or thicker) magnet wire for lifting coil</li><li>6-terminal barrier strip (2 ea.)</li><li>Wood for base and frame</li><li>Alternatives for the LM741 Op-Amp</li></ul><br />I chose the LM741 op-amp out of nostalgia and convenience. It was an extremely successful and common op-amp about twenty years ago.<br /><br />There are lots of modern choices for dual- and quad-package op-amps. By using a package with multiple op-amps, you can reduce the number of parts and lower the cost. For example, you could use a single quad-package op-amp instead of four separate 741s. This would allow a very small printed circuit board to contain all the electronics!<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0zGGq-A39VGKoGhH1WmWYei7OIxteL9SBqURgft1CRi-s9hgC7MHFJ1lfEvLjSN_hw8uKpvnlrOibFCkjsvA2KTyDYNPg7lQjtumai3kDkyt-T97Oc2qYaU7bw2_NNKiBQRKfGjjdTkPr/s1600-h/5.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 331px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0zGGq-A39VGKoGhH1WmWYei7OIxteL9SBqURgft1CRi-s9hgC7MHFJ1lfEvLjSN_hw8uKpvnlrOibFCkjsvA2KTyDYNPg7lQjtumai3kDkyt-T97Oc2qYaU7bw2_NNKiBQRKfGjjdTkPr/s400/5.jpg" alt="" id="BLOGGER_PHOTO_ID_5346654870447882530" border="0" /></a><br /></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-57721675986138851712009-06-12T20:32:00.000-07:002009-06-12T23:44:27.758-07:00Electronic StethoscopeStethoscopes are not only useful for doctors, but home mechanics, exterminators, spying and any number of other uses. Standard stethoscopes provide no amplification which limits their use. This circuit uses op-amps to greatly amplify a standard stethoscope, and includes a low pass filter to remove background noise.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1mdr9kA2cAMn5M_Du4gbPvyyeR-0y7aJEcbnRLc1Z8aK_IOy2WhMno17pTi6fA5tjLb196F8uOIeJ5ZUJz-uLYcexrezEbRXwiQbYURVzFZPHieUnZwMcPvNZ8MHdEFFGg0kK6CwNne1E/s1600-h/10.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 271px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj1mdr9kA2cAMn5M_Du4gbPvyyeR-0y7aJEcbnRLc1Z8aK_IOy2WhMno17pTi6fA5tjLb196F8uOIeJ5ZUJz-uLYcexrezEbRXwiQbYURVzFZPHieUnZwMcPvNZ8MHdEFFGg0kK6CwNne1E/s400/10.jpg" alt="" id="BLOGGER_PHOTO_ID_5346699108649035410" border="0" /></a><span class="fullpost"><br /><span style="font-weight: bold;">Parts</span><br /><br /><span style="font-weight: bold;">Part Total Qty. Description</span><br /> <br />R1 ---------------1 ----------- 10K 1/4W Resistor <br />R2 ---------------1 ----------- 2.2K 1/4W Resistor <br />R4 ---------------1------------ 47K 1/4W Resistor <br />R5, R6, R7 -------3------------ 33K 1/4W Resistor <br />R8 ---------------1 ----------- 56K 1/4W Resistor <br />R10 --------------1 ----------- 4.7K 1/4W Resistor <br />R11 --------------1 ------------ 2.2K to 10K Audio Taper Pot <br />R12 --------------1------------ 330K 1/4W Resistor <br />R13, R15, R16---- 3------------ 1K 1/4W Resistor <br />R14 --------------1 ----------- 3.9 Ohm 1/4W Resistor <br />C1, C8 -----------2 ---------- 470uF 16V Electrolytic Capacitor <br />C2 ---------------1-----------4.7uF 16V Electrolytic Capacitor <br />C3, C4 -----------2----------- 0.047uF 50V Metalized Plastic Film Capacitor <br />C5 ---------------1----------- 0.1uF 50V Ceramic Disc Capacitor <br />C6, C7 -----------2----------- 1000uF 16V Electrolytic Capacitor <br />U1 ---------------1 ----------- TL072 Low Noise Dual Op-Amp <br />U4 ---------------1----------- 741 Op-Amp <br />U5 ---------------1----------- LM386 Audio Power Amp <br />MIC --------------1 -----------Two Wire Electret Microphone <br />J1 ----------------1 -----------1/8" Stereo Headphone Jack <br />Batt1, Batt2 ------2----------- 9V Alkaline Battery <br />LED --------------1 ----------- Red/Green Dual Colour Two Wire LED <br />SW ---------------1 ----------- DPST Switch <br />MISC -------------1 ----------- Stethoscope head or jar lid, rubber sleeve for microphone, board, wire, battery clips, knob for R11<br /><br /><span style="font-weight: bold;">Notes</span><br /><ul><li>MIC is an assembly made out of a stethoscope head and electret mic. Cut the head off the stethoscope and use a small piece of rubber tube to join the nipple on the head to the mic.</li><li>Be careful with the volume, as excess noise levels may damage your ears.</li><li>R11 is the volume control.</li><li>The circuit marked as optional is not required for the main circuit to function. The optional circuit blinks an LED to the heartbeat as it is heard by the microphone. Even if the optional circuit is not included, sound will still be heard via the headphone jack.</li></ul></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-78663975724885187432009-06-12T20:30:00.000-07:002009-06-12T23:53:24.622-07:00Muscular Bio-Stimulator<div style="text-align: center;"><span style="font-weight: bold;">Particularly suitable for cellulite treatment</span><br /><span style="font-weight: bold;">3V battery supply, portable set</span><br /></div><br /><span style="font-weight: bold;">Device purpose:</span><br /><br />This is a small, portable set, designed for those aiming at look improvement. The Bio-Stimulator provides muscles' stimulation and invigoration but, mainly, it could be an aid in removing cellulite.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj48mTqujqcoTiCCth9sVlvRsUmrSDNrAZBcJxcB-ZG93HOBmWZ3x3ezE1NNIJ6L3iamxNrwBun1Qfv6u4EW6tM49I7h31i3M9SqI6aD78decOcKuf9FQBx3MDLleC3FaLMZUN5thaZx9Qy/s1600-h/11.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 277px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj48mTqujqcoTiCCth9sVlvRsUmrSDNrAZBcJxcB-ZG93HOBmWZ3x3ezE1NNIJ6L3iamxNrwBun1Qfv6u4EW6tM49I7h31i3M9SqI6aD78decOcKuf9FQBx3MDLleC3FaLMZUN5thaZx9Qy/s400/11.jpg" alt="" id="BLOGGER_PHOTO_ID_5346701312539707106" border="0" /></a><br />Tape the electrodes to the skin at both ends of the chosen muscle and rotate P1 knob slowly until a light itch sensation is perceived. Each session should last about 30 - 40 minutes.<span class="fullpost"><br /><br /><span style="font-weight: bold;">Parts:</span><br /><br /><ul><li>P1______________4K7 Linear Potentiometer</li><li>R1____________180K 1/4W Resistor</li><li>R2______________1K8 1/4W Resistor (see Notes)</li><li>R3______________2K2 1/4W Resistor</li><li>R4____________100R 1/4W Resistor</li><li>C1____________100nF 63V Polyester Capacitor</li><li>C2____________100µF 25V Electrolytic Capacitor</li><li>D1______________LED Red 5mm.</li><li>D2___________1N4007 1000V 1A Diode</li><li>Q1,Q2_________BC327 45V 800mA PNP Transistors</li><li>IC1____________7555 or TS555CN CMos Timer IC</li><li>T1_____________220V Primary, 12V Secondary 1.2VA Mains transformer (see Notes)</li><li>SW1____________SPST Switch (Ganged with P1)</li><li>B1_____________3V Battery (two 1.5V AA or AAA cells in series etc.)</li></ul><br /><span style="font-weight: bold;">Warning:</span><br /><br />The use of this device is forbidden to Pace-Maker bearers and pregnant women.<br />Do not place the electrodes on cuts, wounds, injuries or varices.<br />Obviously we can't claim or prove any therapeutic effectiveness for this device.<br /><br /><span style="font-weight: bold;">Circuit operation:</span><br /><br />IC1 generates 150µSec. pulses at about 80Hz frequency. Q1 acts as a buffer and Q2 inverts the polarity of the pulses and drives the Transformer. The amplitude of the output pulses is set by P1 and approximately displayed by the brightness of LED D1. D2 protects Q2 against high voltage peaks generated by T1 inductance during switching.<br /><br /><span style="font-weight: bold;">Notes:</span><br /><ul><li>T1 is a small mains transformer 220 to 12V @ 100 or 150mA. It must be reverse connected i.e. the 12V secondary winding across Q2 Collector and negative ground, and the 220V primary winding to output electrodes.</li><li>Output voltage is about 60V positive and 150V negative but output current is so small that there is no electric-shock danger.</li><li>In any case P1 should be operated by the "patient", starting with the knob fully counter-clockwise, then rotating it slowly clockwise until the LED starts to illuminate. Stop rotating the knob when a light itch sensation is perceived.</li><li>Best knob position is usually near the center of its range.</li><li> In some cases a greater pulse duration can be more effective in cellulite treatment. Try changing R2 to 5K6 or 10K maximum: stronger pulses will be easily perceived and the LED will shine more brightly.</li><li>Electrodes can be obtained by small metal plates connected to the output of the circuit via usual electric wire and can be taped to the skin. In some cases, moistening them with little water has proven useful.</li><li>SW1 should be ganged to P1 to avoid abrupt voltage peaks on the "patient's" body at switch-on, but a stand alone SPST switch will work quite well, provided you remember to set P1 knob fully counter-clockwise at switch-on.</li><li>Current drawing of this circuit is about 1mA @ 3V DC.</li><li>Some commercial sets have four, six or eight output electrodes. To obtain this you can retain the part of the circuit comprising IC1, R1, R2, C1, C2, SW1 and B1. Other parts in the diagram (i.e. P1, R3, R4, D1, D2, Q2 & T1) can be doubled, trebled or quadrupled. Added potentiometers and R3 series resistors must be wired in parallel and all connected across Emitter of Q1 and positive supply.</li><li>Commercial sets have frequently a built-in 30 minutes timer. For this purpose you can use the Timed Beeper the Bedside Lamp Timer or the Jogging Timer circuits available on this Website, adjusting the timing components to suit your needs.</li></ul></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-56588988163348804972009-06-12T20:12:00.000-07:002009-06-12T23:21:46.653-07:00Automated Crib Lights<span style="font-weight: bold;">Device purpose:</span><br /><br />This circuit is intended to drive the various lights decorating the crib prepared during Christmas season at many homes in Latin Countries, especially for children delight, in order to obtain realistic light-effects.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiW9w4VK3wdF-_P7JlbHAbyA5B4S9PfR_8v0wetUAlUtaWTiIZhNi6uY3uqPop3azPtL2ZfqHKabJX3ufkqxTfDbHf_srNE__M6stCWiQSv3vsuz-CHoarKJTzs_fxejrqUY4A5UYWIaBY3/s1600-h/8.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 342px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiW9w4VK3wdF-_P7JlbHAbyA5B4S9PfR_8v0wetUAlUtaWTiIZhNi6uY3uqPop3azPtL2ZfqHKabJX3ufkqxTfDbHf_srNE__M6stCWiQSv3vsuz-CHoarKJTzs_fxejrqUY4A5UYWIaBY3/s400/8.jpg" alt="" id="BLOGGER_PHOTO_ID_5346692498957030866" border="0" /></a><br /><span style="font-weight: bold;">Features:</span><br /><br /><ul><li>Alternating day and night with lights gradually dimming from full-on to full-off and the opposite.</li><li>Slow turn on of model-houses interior as night approaches, and slow turn off as sun rises, with presettable intensity, thus imitating candles' light for a more realistic effect.</li><li>Flickering ever-running circuit driving bulbs for fires, firesides, lanterns effects etc.</li><li>Total cycle duration: 2 minutes. Day duration: 1 minute, 15 seconds. Night duration: 45 seconds. (All values are approximate).</li></ul><br /><span class="fullpost"><br /><span style="font-weight: bold;">Parts:</span><br /><br /><ul><li>R1___________150K 1/4W Resistor</li><li>R2,R9,R14_____22K 1/4W Resistors</li><li>R3,R11_______220K 1/4W Resistors</li><li>R4,R12________10K 1/4W Resistors</li><li>R5___________100K 1/2W Trimmer Cermet</li><li>R6,R7,R13,R15__1R 1/4W Resistors</li><li>R8____________33K 1/4W Resistor</li><li>R10__________270K 1/4W Resistor</li><li>R16___________47R 1/4W Resistor</li><li>C1,C4________100nF 63V Polyester Capacitors</li><li>C2,C6_________10µF 25V Electrolytic Capacitors</li><li>C3,C5________100µF 25V Electrolytic Capacitors</li><li>D1-D3_______1N4148 75V 150mA Diodes</li><li>IC1___________4060 14 stage ripple counter and oscillator IC</li><li>IC2__________LM324 Low power Quad Op-Amp IC</li><li>IC3__________78L12 12V 100mA Voltage regulator IC</li><li>Q1,Q3,Q5_____BC238 25V 100mA NPN Transistors</li><li>Q2,Q4,Q6_____BD681 100V 4A NPN Darlington Transistors</li><li>J1___________Miniature input socket,</li><li> suited for commercial plug-in variable voltage power supplies </li><li>J2-J5________Two ways output sockets</li></ul><span style="font-weight: bold;">Load requirements:</span><br /><br /><ul><li>Input J1 is connected to a commercial wall plug-in power supply transformer adapter with variable output settled to 12-15Vdc, and a required minimum output capability of 600mA @ 12V. Using a good number of bulbs the output capability must reach about 1.5A.</li><li>Output J2 is connected to a permanently-on 12V 1W blue bulb(s) for night effect.</li><li>Output J3 is connected to several 12V 2.2W bulbs in parallel for sunlight effect. Max. output current: 1.2A (i.e. 6-7 bulbs).</li><li>Output J4 is connected to several 12V 1W or 1/2W micro-bulbs in parallel for house-interiors lights. Max. output current: 600mA (i.e. 7-8 1W bulbs, doubling in number if 1/2W).</li><li>Output J5 is connected to one or several 12V 1W or 1/2W micro-bulbs in parallel for fires, firesides, lanterns effects etc. Max. output current: 600mA (bulbs total number same as above).</li><li>All outputs are current limited, and short-proof for a reasonable lapse of time.</li></ul><span style="font-weight: bold;">Circuit operation:</span><br /><br />IC1 oscillates at a frequency calculated to obtain a pin 2 level change around every minute. IC2A is then enabled to slowly charge and discharge C5 through R10 during a 2 minutes period. IC1 pin 9 drives D2, R3 & C4, generating a sawtooth for IC2C & IC2D comparators. IC2D comparing the voltage at pin 13 with the sawtooth, generates a squarewave with variable mark-space ratio driving the output darlington Q2 for daylight bulbs. IC2B changes its output at a threshold voltage settled by R8 & R9, activating IC2C & Q4 that act like IC2D & Q2 driving model-houses bulbs as evening approaches and turning them off at dawn. R11 & C6 provide slow turn on and off and R5 sets the basic brightness of these bulbs. IC1 pin 7 drives the output darlington Q6 for flickering fires bulbs and R16 prevents them to turn off completely for a more realistic effect. Q1, Q3, Q5 and associated Base resistors provide current limiting.<br /><br /><span style="font-weight: bold;">Notes:</span><br /><br /><ul><li>Total period length can be varied changing C1 and/or R1 values.</li><li>Day-night ratio can be varied changing R10 value slightly.</li><li>Threshold voltage of turn on and off of model-houses lights can be varied changing slightly R8 and/or R9 values.</li><li>Turn on and off speed of model-houses lights can be varied changing R11 value.</li><li>Current limiting can be varied changing Q2, Q4 & Q6 Emitter resistors.</li><li>Heatsinks for Q2, Q4 & Q6 are needed if current limits are increased.</li></ul></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-43709398459657870242009-06-12T20:00:00.000-07:002009-06-12T23:31:17.099-07:00Cranial Electrotherapy Stimulator<span style="font-weight: bold;">Current generated flows through clips placed on the earlobes</span> <span style="font-weight: bold;">Output current adjustable from 80 to 600 microAmperes</span><br /><br /><span style="font-weight: bold;">Device purpose:</span><br /><br />Owing to the recent launching in Europe of Cranial Electrotherapy Stimulation (CES) portable sets, we have been "Electronically Stimulated" in designing a similar circuit for the sake of Hobbyists. CES is the most popular technique for electrically boosting brain power, and has long been prescribed by doctors, mainly in the USA, for therapeutic reasons, including the treatment of anxiety, depression, insomnia, and chemical dependency. CES units generate an adjustable current (80 to 600 microAmperes) that flows through clips placed on the earlobes. The waveform of this device is a 400 milliseconds positive pulse followed by a negative one of the same duration, then a pause of 1.2 seconds. The main frequency is 0.5 Hz, i.e. a double pulse every 2 seconds. Some people report that this kind of minute specialized electrical impulses contributes to achieve a relaxed state that leaves the mind alert.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjI0QY4o0u0PHmWcjomGGYU9E8CMBGOzNlm2BSMoHaFAxTi9Xcq-fiIWHs7l_1Y2GIFzW-qrODRvdOTnxraasoQPymQ7iO5H-0H1OK10B_MB53gNraLYzxbE-coDCUmY1LurzknXYUC_wwu/s1600-h/9.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 196px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjI0QY4o0u0PHmWcjomGGYU9E8CMBGOzNlm2BSMoHaFAxTi9Xcq-fiIWHs7l_1Y2GIFzW-qrODRvdOTnxraasoQPymQ7iO5H-0H1OK10B_MB53gNraLYzxbE-coDCUmY1LurzknXYUC_wwu/s400/9.jpg" alt="" id="BLOGGER_PHOTO_ID_5346695660119604674" border="0" /></a><br />Obviously we can't claim or prove any therapeutic effectiveness for this device, but if you are interested in trying it, the circuit is so cheap and so simple to build that an attempt can be made with quite no harm.<span class="fullpost"><br /><br /><span style="font-weight: bold;">Parts:</span><br /><ul><li>R1_____________1M5 1/4W Resistor</li><li>R2____________15K 1/4W Resistor</li><li>R3___________100K Linear Potentiometer</li><li>R4_____________2K2 1/4W Resistor</li><li>C1___________330nF 63V Polyester Capacitor</li><li>C2___________100µF 25V Electrolytic Capacitor</li><li>D1_____________3mm. Red LED</li><li>IC1___________7555 or TS555CN CMos Timer IC</li><li>IC2___________4017 Decade counter with 10 decoded outputs IC</li><li>SW1___________SPST Slider Switch</li><li>B1______________9V PP3 Battery</li><li>Clip for PP3 Battery </li><li>Two Earclips with wires (see notes)</li></ul><br /><span style="font-weight: bold;">Circuit operation:</span><br /><br />IC1 forms a narrow pulse, 2.5Hz oscillator feeding IC2. This chip generates the various timings for the output pulses. Output is taken at pins 2 & 3 to easily obtain negative going pulses also. Current output is limited to 600µA by R2 and can be regulated from 80 to 600µA by means of R3. The LED flashes every 2 seconds signaling proper operation and can also be used for setting purposes. It can be omitted together with R4, greatly increasing battery life.<br /><br /><span style="font-weight: bold;">Notes:</span><br /><br /><ul><li>In order to obtain a more precise frequency setting take R1=1M2 and add a 500K trimmer in series with it.</li><li>In this case use a frequency meter to read 2.5Hz at pin 3 of IC1, or an oscilloscope to read 400msec pulses at pins 2, 3 or 10, adjusting the added trimmer.</li><li>A simpler setting can be made adjusting the trimmer to count exactly a LED flash every 2 seconds.</li><li>Earclips can be made with little plastic clips and cementing the end of the wire in a position suited to make good contact with earlobes.</li><li>Ultra-simple earclips can be made using a thin copper foil with rounded corners 4 cm. long and 1.5 cm. wide, soldering the wire end in the center, and then folding the foil in two parts holding the earlobes.</li><li>To ensure a better current transfer, this kind of devices usually has felt pads moistened with a conducting solution interposed between clips and skin.</li><li>Commercial sets have frequently a built-in timer. Timing sessions last usually 20 minutes to 1 hour. For this purpose you can use the Timed Beeper the Bedside Lamp Timer or the Jogging Timer circuits available on this website, adjusting the timing components in order to suit your needs.</li></ul></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-6579981610750358792009-06-05T22:49:00.000-07:002009-06-05T23:01:37.800-07:00Active Antenna HF/VHF/UHF, 3-3000MHzIf you have a shortwave or high-frequency receiver or scanner that is struggling to capture signals with a short, whip antenna, and you'd like the kind of performance that a 60-foot 'longwire' antenna can provide but lack the space to put one up, consider building the AA-7 HF/VHF/UHF Active Antenna described in this article. The AA-7 is a relatively simple antenna that is designed to amplify signals from 3 to 3000 MegaHertz, including three recognized ranges: 3-30Mhz high-frequency (HF) signals; 3-300Mhz very-high frequency (VHF) signals; 300-3000MHz ultra-high (UHF) frequency signals. Those bands are typically occupied by shortwave, ham, government, and commercial radio signals.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbrYe6o5fHGI8ZfRj4v5u89YqTMccfsO_PKGrwUO7GkZBV2XZTj7EF6jO4qdvJuZEhw9JyIWWHIBjNvguYomwuI1h2fD5qn0GjujwD9R1vtG5LzwWuCKwwd87tt5uWACyOBRa0nyxzP-rd/s1600-h/9.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 172px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbrYe6o5fHGI8ZfRj4v5u89YqTMccfsO_PKGrwUO7GkZBV2XZTj7EF6jO4qdvJuZEhw9JyIWWHIBjNvguYomwuI1h2fD5qn0GjujwD9R1vtG5LzwWuCKwwd87tt5uWACyOBRa0nyxzP-rd/s400/9.jpg" alt="" id="BLOGGER_PHOTO_ID_5344088991855552178" border="0" /></a><br /><span style="font-weight: bold;">Active Antennas:</span><br /><br />In its simplest form, an active antenna uses a small whip antenna that feeds incoming RF to a pre-amplifier, whose output is then connected to the antenna input of a receiver. Unless specifically designed otherwise, all active antennas are intended for receive-only operation, and thus should not be used with transceivers; transmitting into an active antenna will probably destroy its active components. A well designed broadband active antenna consider field strength of the desired signal (measured in microvolts per meter of antenna length), atmospheric and other noise, diameter of the antenna, radiation resistance, and antenna reactance at various frequencies, plus the efficiency and noise figure of the amplifier circuit itself.<br /><span class="fullpost"><br /><br /><span style="font-weight: bold;">Circuit Description:</span><br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWgYRJDeA29O_Q0_jzWcMk4TxMk80U2Z-9M3LBZa4bN3SPC4rvrcw_-Y1xFu9KTpM-gfeXBgEY314fEH6JR8-3V2FLTA4OU0QoebFmp1AxNIOJ3KUXr9m1s4XzaOymOqjSPgJKaljuCNls/s1600-h/8.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 352px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWgYRJDeA29O_Q0_jzWcMk4TxMk80U2Z-9M3LBZa4bN3SPC4rvrcw_-Y1xFu9KTpM-gfeXBgEY314fEH6JR8-3V2FLTA4OU0QoebFmp1AxNIOJ3KUXr9m1s4XzaOymOqjSPgJKaljuCNls/s400/8.jpg" alt="" id="BLOGGER_PHOTO_ID_5344088990723973762" border="0" /></a><br />Figure shows the schematic diagram of the AA-7, which contains only two active elements; Q1 (an MFE201 N-Channel dual-gate MOSFET) and Q2 (a 2SC2570 NPN VHF silicon transistor). Those transistors provide the basis of two independent, switchable RF pre-amplifiers. Two double-pole double-throw (DPDT) switches play a major role in this operation of the AA-7. Switch S1 is used to select one of the two pre-amplifier circuits (either HF or VHF/UHF). Switch 2 is used to turn off the power to the circuit, while coupling the incoming RF directly to the input of the receiver. That gives the receiver non-amplified access to the auxiliary antenna jack, at J1, as well as the on-board telescoping whip antenna. With switch S2 in its power-on position, the input and output jacks are disconnected and B1 (a 9 volt battery) is connected to the circuit. With switch S1 in the position shown in the schematic, incoming RF is directed to the HF pre-amp circuit built around Q1 (an MFE201 N-Channel dual-gate MOSFET). The HF pre-amp operates with an exceptionally low noise level, and is ideal for copying weak CW and singe-side band signals. When S1 is switched to the other position, the captured signal is coupled to the VHF/UHF pre-amp built around Q2 (a 2SC2570 NPN VHF silicon transistor), which has excellent VHF through microwave characteristics. With the on-board whip antenna adjustable to resonance through much of the VHF-UHF region (length in feet = 234 divide by the frequency in MHz), the VHF/UHF mode is ideal for indoor and portable use with VHF scanners and other receivers. Either mode can be used when tuning 3-30 MHz HF signals. The VHF/UHF pre-amp offers higher gain than the HF pre-amp, but also has a higher noise level. You can easily choose either amplifier for copying any signal; of interest--just try both positions. The RF gain control (R5) can be used to trim the output of either amplifier.<br /><br />Caution: The AA-7 is not intended for transmitting operation (be it Ham, Maritime, or CB); if it is used with a transceiver of any kind, make sure it is not possible to transmit by accidentally pressing a mike button or CW keyer. Transmitting RF into the AA-7 is likely to ruin one or both of the transistors in the circuit.<br /><br /><span style="font-weight: bold;">Parts List and other components:</span><br /><br /><span style="font-weight: bold;">Semiconductors:</span><br /><br />Q1 = MFE201, SK3991, or NTE454. N-Channel, dual-gate MOSFET, TO-72 (see text)<br />Q2 = 2SC2570, NTE107. Silicon RF IF/Amp, NPN transistor (see text)<br /> Note: If you use the NTE107 as a replacement, make sure to insert it correctly<br /> into the pcb. The orientation is different than as shown on the parts layout<br /> diagram. (e-c-b seen front view for NTE107). See this Data Sheet<br /><br /><span style="font-weight: bold;">Resistors:</span><br /><br />All Resistors are 5%, 1/4-watt<br />R1 = 1 Mega Ohm<br />R2 = 220K<br />R3,R6 = 100K<br />R4 = 100 ohm<br />R5 = 10K potentiometer (pc mount)<br /><span style="font-weight: bold;">Capacitors:</span><br /><br />C1,C2,C5,C6 = 0.01uF, ceramic disc<br />C3 = 100pF ceramic disc<br />C4 = 4.7 to 10uF, 16WVDC, radial lead electrolytic<br /><br /><span style="font-weight: bold;">Additional Parts & Materials: </span><br /><br />B1 = 9-volt alkaline battery<br />S1,S2 = DPDT PC mount pushbutton switch<br />J1,J2 = PC mount RCA jack<br />ANT1 = Telescoping whip antenna (screw mount)<br />MISC = PCB materials, enclosure, enclosure, battery holder and connector,<br /> wire, solder, etc.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-24731519465989318792009-06-05T22:29:00.000-07:002009-06-05T22:36:26.579-07:00Motorcycle Battery ChargerThis 3A charger was originally designed to work with small batteries like those used in motorcycles. In principle it can be used to charge car batteries also but will take a lot longer.<br />The charger below charges a battery with a constant current to 14.1 volt. When this level is reached, the current charge drops automatically to a safer level (13.6V) and keeps charging at this slower rate untill the LED lights up indicating a fully charged battery. This project looks very much alike with the Gel cell II charger elsewhere posted in the 'Circuits' section. The difference is the IC, namely a LM1458 instead of a LM301A. Nice job Jan!<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFFOxPERmnS5V4vZ1dY81f35kfWqi9TgL5kG0Ca3McNf69TfDp5aOLjcZQx9fd_wgrO1tKeB0TG3Hyj9uiRMabJOasnmlbHt542gtGk7kYT8yd8ZEqNGowVf4THWhMZpTVzjcbfpxihXER/s1600-h/6.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFFOxPERmnS5V4vZ1dY81f35kfWqi9TgL5kG0Ca3McNf69TfDp5aOLjcZQx9fd_wgrO1tKeB0TG3Hyj9uiRMabJOasnmlbHt542gtGk7kYT8yd8ZEqNGowVf4THWhMZpTVzjcbfpxihXER/s400/6.jpg" alt="" id="BLOGGER_PHOTO_ID_5344083989519979506" border="0" /></a><span class="fullpost"><br /><br /><span style="font-weight: bold;">Description:</span><br /><br />The LM350 is an adjustable voltage regulator and keeps the voltage between points C and B at 1.25 Volt. By adding a 1K resistor between point B and gnd (-) you can, as it were, lift up the output voltage. To accurately control the output voltage we add to this resistor, in series, a 2K adjustable 10-turn potentiometer. As soon as a battery is connected a current flow occurs, controlled by the right halve of the LM1458. The current through the 0.1 ohm resistor causes a voltage drop. This drop is compared with the voltage on the walker of 100-ohm pot. The moment this drop is greater than the one adjusted with the potmeter will cause the output of the LM1458 IC to go low and a small current starts to flow thru the diode and this in effect will reduce the current through the series resistors 1K + 2Kpot. The current is hereby stabilized.<br /><br />The point between C and B is devided by three resistors; 2.2 ohm, 100 ohm pot, and the 150 ohm. 2.2 ohm and the 100 ohm potmeter are connected to the non-inverting input (+) of the LM1458 IC. The inverting input (-) is connected to the 0.1 ohm wire-wound resistor in series with the output. As long as the voltage drop, caused by the current-flow over this resistor is greater than the voltage drop over the 2.2 ohm resistor the output of the LM1458 will stay high and in turn block the BC558 transistor. But as soon as the charge current falls below a specific value the 1458 will go low and turn on this transistor which wich activate the LED. At the same time a small current will flow thru the 'Rx' resistor, which will cause that the output voltage of the charger switches to 13.6 Volt. This is a very safe output voltage, and does not cause overcharging to the battery and remains fully charged (trickle).<br /><br />Rx should be an experimental value determined below; a mathematically calculation is possible but the exact value is determined by the tolerances of your specific components.<br /><br />The voltage regulator LM350 has to dissipate a lot of energy so make sure to mount it on a large cooling fin. (e.i. 3.3°C/Watt) Diode 1N4001 over the input/output is necessary to prevent damage to the regulator in case the input voltage gets interrupted.<br /><br />The LM350 can be substituted with a NTE970, and the BC558B with a NTE159 if you wish.<br />The adjustments for this charger are really simple and the only thing needed is digital multimeter. The LM1458 should NOT be in the socket while doing the first adjustment. When no battery is connected there is no current flow thru the 0.1 ohm resistor and therefore pulling the output low. So no IC yet in the socket. Do NOT connect a battery also. I know that is obvious to most of us, but some people... :-)<br /><br />Okay, here we go:<br /><ol><li>Connect the multimeter (set for Volt DC) to the '+' and '-' battery output and adjust with the 2k trimpot the output voltage to 14.1 Volt.</li><li>Switch the power off. Discharge the capacitors (short them out with a piece of wire).</li><li>Now insert the LM1458 IC carefully (check no pins are bend underneath the chip).</li><li>Switch the power back on and make the resistor marked Rx such a value that the output voltage reads 13.6 volt exactly.</li><li>Switch the multimeter to 'Amp-dc'. Turn the 100-ohm trimpot all the way CCW. Connect the 'to-be-charged-battery' (e.i. NOT a fully charged battery) and turn back the trimpot untill the current load is 0.1 X the battery capacity (max 3A). Example: A 16Amp battery adjusting to 1.6A. If you don't have an Amp meter on your multimeter you can use the 2-volt setting on your meter and connect it over the 0.1 ohm resistor. The current is volt devided by 0.1, so for 3A the meter should read 0.3 volt.</li></ol><br />That's it. To get the Rx value you could also use a trimpot until you get the 13.6volt and then read the ohm's value of the trimpot and replace with a resistor. In my opinion this resistor should be a metalfilm type at 1 or 2% tolerance.<br /><br />The Technical bits:<br /><br />For those of you interested in how the value of essential components was calculated, read on. You may be able to design your own charger for use with a different current or voltage (like 6-volt).<br />Calculations origin from the voltage between points C and B of the LM350 regulator. When a resistor is connected between these two points, enough current starts to flow that the voltage over this resistor measures 1.25 volt. In our case, the resistor total is 2.2 + 100 + 150 =252.2 ohm. Because we deal with very small currents the calculations are performed in milliamps and the calculations of resistance in Kilo-Ohms. Thus, the current thru this resistor is 1.25 / 0.2522 = 4.9564 mA. The same current also flows thru the 1K & 2K series resistors. We want the output voltage to be 14.1 volt, meaning the voltage drop over these series resistors must be 14.1 - 1.25 = 12.85 Volt.<br /><br />The total resistance value thus must be 12.85 / 4.9564 = 2.5926 Ohms. To enable us to adjust it to this value, one of the resistors is chosen as a 10-turn trimpot (trimmer potentiometer). Together with the 1K in series (making it a total of 3K)we can adjust it to this correct value.<br /><br />The Rx value is calculated this way; In this scenario we like to have a output voltage of 13.6 volt, in other words, the voltage on the connection point between the 1K/2Kpot should be 13.6 - 1.25 = 12.35 volt. This means that the current thru the 'voltage-divider' will be 12.35 / 2.5926 = 4.7635 mA and the leftover current should be 4.9564 - 4.7635 = 0.1929 mA thru Rx and also cause a voltage drop of 12.35 - 2.78 = 9.57 volt. Measuring this calculated value at the base of the BC558 transistor was 2.78 volt after the output of the LM1458 had become low. With the current of 0.1929 mA the result has become9.47 / 0.1929 = 49.611 Kilo-Ohm. A resistor of 47K would come close enough. Ofcourse you could also use a 50K trimpot to adjust the value even more accurately. The 1K5 (1500 Ohm) resistor in series with the LED is to limit the current thru the LED below 20 mA.<br /><br />The only thing left is to calculate the value of the series resistor which determines the switch-over from charge to float condition. This occurs when the voltage drop over the 0.1 ohm (wire-wound) resistor at the positive leg smaller is than over the 2.2 ohm resistor. This value is 2.2 x 4.9564 = 10.9 mV. The resistance is 0.1 ohm, to get a voltage drop over this resistor of 10.9 mV is the current 10.9 x 0.1 = 109 mA. The second this charge current becomes lower then 109 mA, the LM1458 triggers over to the float condition.<br />The adjustment with the 100-ohm trimpot determines the maximum charge current. The voltage on the walker of this trimpot varies between 10.9 mV - 506.54 mV. The current is this way made adjustable between 0.1A - 5A, but we should not go that far because the LM350K can not handle anything over 3Amp. If we chose a trimpot with a value of 50 ohm, then on the other hand the 3A can not be obtained. So, careful adjustment is the remedy. Take your time!<br /><br />With this information it is a simple task to calculate the dissipation values of the resistors. In other words, the product of the resistance multiplied with the current in square (I2xR).<br /><br />The only resistor which gets it difficult is the 0.1 ohm, but then again, not by much 3 x 3 x 0.1 = 0.9 Watt.<br />Rest us to calculate the power. For that we have add a couple of voltages. We have the input voltage of 14.1, the voltage drop over the resistor, 0.1 x 3 = 0.33 volt, and 3 volt minimum over the LM1458 for proper function, total 17.43 volt. The transformer provides 18V (effective). With ideal rectifying this should total 18 x 1.41 = 25.38 volt. There are however losses via the diodes and bridge rectifier so there is about 23.88 volt remaining. Not much tolerance to play with, on the other hand, too much causes energy loss in the form of heat anyway.<br />The voltage drop over the buffer capacitor may not be lower than 17.43 volt, meaning, the ripple voltage may reach about 23.88 - 17.43 = 6.45 volt. By double-fase rectifying is the ripple voltage equal to I/(2xfxC) whereby I is the discharge current, f is the supply frequentie and C is capacity of the buffer capacitor in Farad. Exchanging places this would give C = 3/(2x50x6.45) = 0.004651 Farad, or 4651 uF. A standard value of 4700 uF with a minimum voltage value of about 35-40 Volt. The other capacitor is not very critical and is only there to kill small voltage spikes which could influence the operation of this charger otherwise.<br /><br />The bridge rectifier gets a good workout also and it is therefore recommended to chose NOT a too light a unit. A 5A rectifier is often too small, better to take a 8 or 10A type. These are readily available everywhere.<br /><br />Last but not least, the transformer. The buffer capacitor has approximately 25 volt accros. The current is 3A. This calculates to a power of 25 x 3 = 75 watt. This transformer has its own problems with powerloss (naturely occuring) and so a unit of about 80 watt is acceptable.<br />Never attempt to charge a 6 volt battery with a 12 volt charger; you are asking for trouble. Good luck all!</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-87752518386344547622009-06-05T22:07:00.000-07:002009-06-05T22:19:28.896-07:00Foam Cutting Power SupplyAfter seeing other modelers building their model wings from plastic foam, I decided that I wanted to do the same. Building your wings from foam covered with 1/16 in. balsa can produce a strong and light wing that could be difficult to duplicate with the standard balsa rib construction, especially if the wing had a duel tapered, symmetrical airfoil. The standard way to cut foam is with the Hot Wire technique, using steel or nichrome wire through which an electrical current flows to heat the wire.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfya-HxpGQHtcxj3xcv48sUHGKA3nP7zgyWEhm0UO31dzjuqSk543W8gnlapCxOFehGkJyNCIGH2Dh7xFmczKkGJuZvDZQx9MvbRZ7CKt5-gWF7w8DIQ_pgU1aTajfL5VoUG0tX26adCEv/s1600-h/7.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 258px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfya-HxpGQHtcxj3xcv48sUHGKA3nP7zgyWEhm0UO31dzjuqSk543W8gnlapCxOFehGkJyNCIGH2Dh7xFmczKkGJuZvDZQx9MvbRZ7CKt5-gWF7w8DIQ_pgU1aTajfL5VoUG0tX26adCEv/s400/7.jpg" alt="" id="BLOGGER_PHOTO_ID_5344077683136718786" border="0" /></a><br />However, the methods that many use to get the wire hot leaves something to be desired. The most common method I saw used was to connect a 12volt battery charger to 4 or 5 feet of nichrome wire which was tied to some kind of a bow. Using the variable charging rate, you could control (to a limited degree) the temperature of the wire and thus the speed of the cut. But if you cannot accurately control the heat, you'll get many poor cuts. Some have connected a series of light bulbs in line with the wall service of 115 volts AC.<span class="fullpost"><br /><br />It works, but WOW, is it ever dangerous! Terrible shock hazard! I've even seen some connect the nichrome wire across a 12 volt car battery, also very dangerous. Over the years there have been several schematics listed in the model magazine for building a hot wire foam cutter power supply. All of them worked, I'm sure. Some were very simple, but left little heat control, and others were complex and expensive. Heat control is the secret for making good foam cuts. Also a good transformer is important for removing the electrical shock hazard that threatens the modeler in his shop. A good current limiting feature also makes the device safe from high current burns, which some auto mechanics have suffered when working with large 12 volt batteries.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZHk3UutS1pSZr6UGPdJksfVxtMpqkWpBL1XvEG1rmAv6t0QiL25FElldprMZ68zBNgMY8RyNlExVPKS2tyJQzSQTF7nfxlJRvJcXxbyiA_zCe5-cKX47XNXmhvg4J0T5j9nyn23Da8lWi/s1600-h/3.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 174px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZHk3UutS1pSZr6UGPdJksfVxtMpqkWpBL1XvEG1rmAv6t0QiL25FElldprMZ68zBNgMY8RyNlExVPKS2tyJQzSQTF7nfxlJRvJcXxbyiA_zCe5-cKX47XNXmhvg4J0T5j9nyn23Da8lWi/s400/3.jpg" alt="" id="BLOGGER_PHOTO_ID_5344077670712118530" border="0" /></a><br />The following circuit is a simplification of several older designs. This design uses readily available parts, is easy to build, has total temperature control for both a long bow (48") and a short bow (24"), and has served me well for the last 15 years. Many of the planes that I fly are my own design and I build most of them with foam wings, foam turtle decks, foam stabs, etc, usually with dual tapered, symmetrical designs. The short bow is valuable for sculpting foam pieces into various shapes, as it can be held in one hand and the foam sample in the other.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_WTFQG4X7lQRfdcGPvBap0UBI9pR1xELGnlK_LA-YUu80-BQ1P7Jl9QJCeYv2piq3kG6_nFOGH9JboiI4fvTS8hF69AVMSoGTnZOzx3FDwHnYa2tqRYSCCdkjc1k12TNu4TUXjiS0axsD/s1600-h/4.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 264px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_WTFQG4X7lQRfdcGPvBap0UBI9pR1xELGnlK_LA-YUu80-BQ1P7Jl9QJCeYv2piq3kG6_nFOGH9JboiI4fvTS8hF69AVMSoGTnZOzx3FDwHnYa2tqRYSCCdkjc1k12TNu4TUXjiS0axsD/s400/4.jpg" alt="" id="BLOGGER_PHOTO_ID_5344077673923782162" border="0" /></a><br /><br />The first step in building one of these foam cutters is to take the Bill of Materials to your local Radio Shack and search for the parts. I picked this source because of shopping convenience and the total cost is a little above $30. Also get a small copper clad circuit board (CB), about 3 by 4 inches or larger in size. If you chose not to make the circuit board, you can solder the parts together using electrical stand-offs. The first order of business is to mount the switches, the potentiometer, the Red and Black electrical posts (#274-662), and the red indicator light on the front panel of the component box according to the picture and illustration. Next mount the transformer (#273-1512), fuse holder (#270-364), and electrical cord (#278-1255) in the box as shown in photo. Put some rubber feet on the bottom of the box (also from Radio Shack) so that it won't scratch your wife's end table when you take it to show her what a great craftsman you are.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBqIgt1f7qR7xBkyhCpTdTYq_PPcf3mrnkqJXnb30PbHepmoJMCwaAab4qLywp-rRE03EVCRqzBPkpHf8XzxE9OHE9ndc1BFABWSTVnPlOX2EAn-vJRwbidOAVWRH7FcC0Wvk563IW68MP/s1600-h/5.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 328px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBqIgt1f7qR7xBkyhCpTdTYq_PPcf3mrnkqJXnb30PbHepmoJMCwaAab4qLywp-rRE03EVCRqzBPkpHf8XzxE9OHE9ndc1BFABWSTVnPlOX2EAn-vJRwbidOAVWRH7FcC0Wvk563IW68MP/s400/5.jpg" alt="" id="BLOGGER_PHOTO_ID_5344077678034953458" border="0" /></a><br />The circuit is a simple AC Triac voltage control circuit similar to the ones used to control house lamps. The transformer provides the electrical isolation the makes this item safe to operate. The voltage at the bow will tingle a little, but will not harm the operator. The OFF/ON switch is a simple s.p.s.t. switch (#275-651). The "Long/Short" Bow selector switch is the same part number. Across the primary side of the transformer is mounted an indicator "ON" lamp (#272-712) which will light up when the unit is turned on. The temperature control is through the 5k ohm potentiometer R2 (#271-1714). The Triac gate current is controlled by R3, a 470 ohm, 1 watt resistor. This resistor is not part of radio Shack's inventory, therefore it may be required to solder two 1k ohm, 10 watt resistors in parallel. The capacitor, C1, is a 0.22microF disk (#272-1070). The 5 ohm, 20 watt resistor R1 is made of two 10 ohm, 10 watt resistors in parallel. They are large ceramic resistors mounted side by side. These resistors drop the voltage when the short 24" bow is being used. These resistors will get hot, don't touch!<br /><br />Enclosed in this article is a actual size drawing of the circuit board (CB, 2.5" x 4"). Cut out this drawing and use it as a template, and paste it on the side opposite of the copper on the CB (circuit board) with some rubber cement. Next use a center punch to mark the center of each hole. Then drill the holes with the CB held tightly to some wood backing, making the four corner holes a 1/8" in dia and all the rest about 1/16" in dia. These smaller holes will be where you solder the components and wires. The larger holes are for the mounting bolts to hold the CB to the case. Cut the CB to the exact size as shown on the template (2.5" x 4"). Then, print out the copper side drawing and paste it on the copper side of the board. Use a sharp X-acto knife to remove thin strips of copper as shown. This will isolate the copper soldering pads from one another. Remove the paper. Insert the components in the CB on the side opposite the copper. Where the component leads stick out on the copper side, solder the component leads to the board being careful not to allow solder to bridge the cut lines in the copper. Cut off any excessive lead after soldering it. Bolt the Heat Sink on to the Triac with the fins pointing out. The Triac should be mounted in a vertical position, perpendicular to the CB. Next mount the CB in the box with 6-32 x 1" bolts and stand-offs. Finish soldering the connecting wires to the board before tightening the bolts. Drill 3 or 4 vent holes (1/4" dia) in the top of the box in the area above the Triac heat sink.<br /><br />Plug the nichrome wire bow leads into the dual plug speaker connectors. It is best to trim the wire insulation on the wires back about 1/2 in. then tin the wire ends. After the wires are plugged in, turn the unit on and with the temperature control at half point and the heat switch set up to long. The wire should get hot to the touch almost immediately. If it doesn't, then examine the construction on the circuit board and wiring, and fix any errors found. After the unit is finished, bolt the top on and your and you're done.<br /><br />When you use the foam cutter, be sure that the Bow switch is in the correct position. The switch must be in the "Short" position (down) if the 24" bow is used. Otherwise you may blow the fuse. Leave the unit in the "Long" bow position at all times unless you are using the short bow and you should have no problems. Before you turn the Foam Cutter on, turn the temperature (TEMP) control fully counter-clockwise, to minimum temperature. Turn the unit on with a bow plugged in and increase the temperature by turning the TEMP knob clockwise. The temperature of the wire increases almost immediately. With a piece of foam, test for the foam cutting temperature. Reduce the TEMP control until the cut is smooth with little foam evaporation around the wire. Remember, the smoothest cuts are made slowly. Spend some time practicing until your cuts are smooth. You will never go back to balsa ribs! </span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-25977061291122469072009-06-05T21:03:00.000-07:002009-06-05T21:09:45.742-07:00Lead Acid Battery Charger<span style="font-weight: bold;">Parts List:</span><br /><br />C1 = 100uF/63V<br />C2 = 10uF/63V<br />D1 = 1N5401/NTE5801<br />D2 = LED (Red, 5mm)<br />Q1 = NTE374/BD140<br />Q2 = NTE123AP/BC547<br />R1 = 120 Ohm <br />R2 = 82 Ohm <br />R3 = 10K <br />R4 = 33K <br />R5 = 22K<br />P1 = 2K2<br />U1 = LM350 (On large coolrib!)<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5u8voX2GbOu7tW-D_E1rWWtQ8xcmIQUxOO5r6S1oEqn_EdDYhDNh-lUQMtUB1kqybBH_zqpbeBhqtbQREVj4oaK76hCPajdcbP3NGa90i0gXFQLPhVLmi92WP8Cck5Pyl4bHiPTeIsysx/s1600-h/2.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 321px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5u8voX2GbOu7tW-D_E1rWWtQ8xcmIQUxOO5r6S1oEqn_EdDYhDNh-lUQMtUB1kqybBH_zqpbeBhqtbQREVj4oaK76hCPajdcbP3NGa90i0gXFQLPhVLmi92WP8Cck5Pyl4bHiPTeIsysx/s400/2.jpg" alt="" id="BLOGGER_PHOTO_ID_5344061221283729266" border="0" /></a><br /><span style="font-weight: bold;">How it works:</span><br /><br />Except for use as a normal Batter Charger, this circuit is perfect to 'constant-charge' a 12-Volt Lead-Acid Battery, like the one in your flight box, and keep it in optimum charged condition. This circuit is not recommended for GEL-TYPE batteries since it draws to much current.<br /><br />The above circuit is a precision voltage source, and contains a temperature sensor with a negative temperature coëficient. Meaning, whenever the surrounding or battery temperature increases the voltage will automatically decrease. Temperature coëficient for this circuit is -8mV per °Celcius. A normal transistor (Q1) is used as a temperature sensor.<span class="fullpost"><br /><br />This Battery Charger is centered around the LM350 integrated, 3-amp, adjustable stabilizer IC. Output voltage can be adjusted with P1 between 13.5 and 14.5 volt. T2 was added to prevent battery discharge via R1 if no power present. P1 can adjust the output voltage between 13.5 and 14.5 volts. R4's value can be adjusted to accommodate a bit larger or smaller window. D1 is a large power-diode, 100V PRV @ 3 amp. Bigger is best but I don't recommend going smaller.<br /><br />The LM350's 'adjust' pin will try to keep the voltage drop between its pin and the output pin at a constant value of 1.25V. So there is a constant current flow through R1. Q1 act here as a temperature sensor with the help of components P1/R3/R4 who more or less control the base of Q1. Since the emitter/base connection of Q1, just like any other semiconductor, contains a temperature coëficient of -2mV/°C, the output voltage will also show a negative temperature coëficient. That one is only a factor of 4 larger, because of the variation of the emitter/basis of Q1 multiplied by the division factor of P1/R3/R4. Which results in approximately -8mV/°C. To prevent that sensor Q1 is warmed up by its own current draw, I recommend adding a cooling rib of sorts.<br />(If you wish to compensate for the battery-temperature itself, then Q1 should be mounted as close on the battery as possible) The red led (D2) indicates the presence of input power.<br /><br />Depending on what type of transistor you use for Q1, the pads on the circuit board may not fit exactly (in case of the BD140).<br /><br />Caution: Adjust the voltage of capacitor C1 according to the input voltage. Example, if your input voltage will be 24 volt, your C1 should be able to carry at least 50V.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-39966772345220228132009-06-05T19:39:00.000-07:002009-06-05T20:45:49.732-07:00IC Controlled Emergency Light with ChargerThe circuit shown here is that of the IC controlled emergency light. Its main features are: automatic switching-on of the light on mains failure and battery charger with overcharge protection. When mains is absent, relay RL2 is in deenergised state, feeding battery supply to inverter section via its N/C contacts and switch S1. The inverter section comprises IC2 (NE555) which is used in stable mode to produce sharp pulses at the rate of 50 Hz for driving the MOSFETs. The output of IC3 is fed to gate of MOSFET (T4) directly while it is applied to MOSFET (T3) gate after inversion by transistor T2. Thus the power amplifier built around MOSFETs T3 and T4 functions in push-pull mode.<br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsEHkxA-QK6-rRpmgzrU7P1YQyxyS512tazqtJn1BXzEOx539LgwReBuwuoSesguKnkCIU66CCcLw8UWvgT4j9u_5K4QKVd_7xQbyTKbSQsm1Piegcx06uJwx7iqUuWp37a5tMd9KIH3aP/s1600-h/1.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 392px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsEHkxA-QK6-rRpmgzrU7P1YQyxyS512tazqtJn1BXzEOx539LgwReBuwuoSesguKnkCIU66CCcLw8UWvgT4j9u_5K4QKVd_7xQbyTKbSQsm1Piegcx06uJwx7iqUuWp37a5tMd9KIH3aP/s400/1.jpg" alt="" id="BLOGGER_PHOTO_ID_5344055402539278642" border="0" /></a><br />The output across secondary of transformer X2 can easily drive a 230-volt, 20-watt fluorescent tube. In case light is not required to be on during mains failure, simply flip switch S1 to off position.<span class="fullpost"><br /><br />Battery overcharge preventer circuit is built around IC1 (LM308). Its non inverting pin is held at a reference voltage of approximately 6.9 volts which is obtained using diode D5 (1N4148) and 6.2-volt zener D6. The inverting pin of IC1 is connected to the positive terminal of battery. Thus when mains supply is present, IC1 comparator output is high, unless battery voltage exceeds 6.9 volts. So transistor T1 is normally forward biased, which energises relay RL1. In this state the battery remains on charge via N/O contacts of relay RL1 and current limiting resistor R2. When battery voltage exceeds 6.9 volts (overcharged condition), IC1 output goes low and relay RL1 gets deenergised, and thus stops further charging of battery. MOSFETs T3 and T4 may be mounted on suitable heat sinks.<br /></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-70848107268243393782009-06-03T09:44:00.000-07:002009-06-03T09:47:51.341-07:00Precision Metronome & Pitch generator<div style="text-align: center;"><span style="font-weight: bold;">Precision Frequency generator 1 to 999 Hz </span><br /><span style="font-weight: bold;">Precision Metronome 1 to 999 beats per minute</span><br /></div><br /><span style="font-weight: bold;">Circuit Diagram:</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF156TK-u8YgsEfJhBtQZXVlvokF8t5pcWfJMe1nq44zOBQ6nzH9BgWKymiNK-RppiM5SM9iibEWZhwhC0Mnk2C7ePULamY84ZkoEXhS4T98FDGMCoNc8YPkGIItBOci_9qLYyjEHxuBS2/s1600-h/2.GIF"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 315px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF156TK-u8YgsEfJhBtQZXVlvokF8t5pcWfJMe1nq44zOBQ6nzH9BgWKymiNK-RppiM5SM9iibEWZhwhC0Mnk2C7ePULamY84ZkoEXhS4T98FDGMCoNc8YPkGIItBOci_9qLYyjEHxuBS2/s400/2.GIF" alt="" id="BLOGGER_PHOTO_ID_5343143737261197554" border="0" /></a><br /><span style="font-weight: bold;">Parts:</span><br />R1__________1M 1/4W Resistor<br />R2_________22K 1/4W Resistor<br />R3__________6K8 1/4W Resistor<br />R4__________4K7 1/4W Resistor<br />R5_________47K 1/4W Resistor<br />R6________100K 1/4W Resistor<span class="fullpost"><br />R7_________39K 1/4W Resistor<br />R8_________12K 1/4W Resistor<br />C1_________47pF 63V Ceramic Capacitor<br />C2_______2-22pF 63V Ceramic Trimmer<br />C3________470pF 63V Ceramic Capacitor<br />C4_________10pF 63V Ceramic Capacitor<br />C5________100nF 63V Polyester Capacitor<br />C6________220nF 63V Polyester Capacitor<br />C7_________22µF 25V Electrolytic Capacitor<br />D1-D15___1N4148 75V 150mA Diodes<br />IC1________4060 14 stage ripple counter and oscillator IC<br />IC2________4082 Dual 4 input AND gate IC<br />IC3________4520 Dual binary up-counter IC<br />IC4________4518 Dual BCD up-counter IC<br />IC5________4046 Micropower Phase-locked Loop IC<br />IC6________4040 12 stage ripple counter IC<br />Q1________BC337 45V 800mA NPN Transistor<br />XTAL______2.4576 MHz Miniature quartz crystal<br />SW1__________BCD Miniature Thumbwheel Switch (units)<br />SW2__________BCD Miniature Thumbwheel Switch (tens)<br />SW3__________BCD Miniature Thumbwheel Switch (hundreds)<br />SW4_________SPST Slider Switch (On-off)<br />SW5_________SPDT Slider Switch (Metronome-Pitch)<br />SPKR_______8 Ohm, 50 mm. Loudspeaker<br />B1_________9V PP3 Battery<br />Clip for 9V PP3 Battery<br /><br /><span style="font-weight: bold;">Circuit operation:</span><br /><br />CMos IC1 and IC2B quad AND gate form a 2.4576 MHz crystal oscillator plus a 2400 times divider. IC3A provides further division by 16, delivering a 64 Hz stable frequency square wave. This frequency is multiplied (by means of Phase Locked Loop IC5, double decade divider IC4 and IC3B 4 bit binary divider) by the number set by three miniature BCD thumbwheel switches SW1, SW2 and SW3: units, tens and hundreds respectively.<br /><br />Connecting, by means of SW5, Q1 base to pin 2 of IC6, we obtain (after a 64 times division) the same frequency set by thumbwheel switches with quartz precision, and no need for a scale indicator.<br /><br />Volume regulation of the pitch generator is obtained trimming resistor R5. In the same way, with SW5 set to metronome, the small speaker reproduces the frequency set by thumbwheel switches but divided by 3840, thus obtaining beats per minute ratio.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-17013792154302183762009-06-03T09:36:00.000-07:002009-06-03T09:42:10.141-07:00Fuzz-box<span style="font-weight: bold;">All-FET design Valve-like distortion behavior</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKiju09tSh7gZ3wTYGVn6h-sFVU51ATu2aoHNR2dML25DDlmr7qAEw5G7XvNs3W6YOCnqk41Djy1swcS6B_nGfKtJGc8-VxOQhT-gUPZnkFED8C2tPpqF6rvxJmRPUmtw-e4j9RSXSpnXJ/s1600-h/1.GIF"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 385px; height: 289px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKiju09tSh7gZ3wTYGVn6h-sFVU51ATu2aoHNR2dML25DDlmr7qAEw5G7XvNs3W6YOCnqk41Djy1swcS6B_nGfKtJGc8-VxOQhT-gUPZnkFED8C2tPpqF6rvxJmRPUmtw-e4j9RSXSpnXJ/s400/1.GIF" alt="" id="BLOGGER_PHOTO_ID_5343141978118245106" border="0" /></a><br /><span style="font-weight: bold;">Parts:</span><br /><br />P1______________10K Log. Potentiometer<br />R1_______________1M 1/4W Resistor<br />R2_______________3K3 1/4W Resistor<br />R3_______________2K2 1/4W Resistor<br />R4_______________5K 1/2W Trimmer (Cermet)<br />R5_____________100K 1/4W Resistor<br />C1,C4__________100nF 63V Polyester Capacitors<br />C2_____________100pF 63V Ceramic Capacitor<br />C3,C5___________22µF 25V Electrolytic Capacitors<br />Q1,Q2,Q3______2N3819 General-purpose N-Channel FETs<br />J1,J2__________6.3mm Mono Jack sockets<br />SW1_____________DPDT Toggle - Slider or Pedal Switch<br />SW2_____________SPST Toggle or Slider Switch<br />B1________________9V PP3 Battery<br />Clip for PP3 Battery<br /><span class="fullpost"><br /><span style="font-weight: bold;">Comments:</span><br /><br />This circuit was designed to obtain a valve-like distorted sound from an electric guitar or other musical instrument.<br /><br />For this purpose a very high gain, three-FET amplifier circuit, was used. The output square wave shows marked rounded corners, typical of valve-circuits when driven into saturation.<br /><br />Therefore, the distorted sound obtained from such a device has a peculiar tone, much loved by most leading guitarists.<br /><br /><span style="font-weight: bold;">Technical data:</span><br /><br /><ol><li>Input sensitivity: 30mV RMS.</li><li>Output square wave: 6V peak-to-peak max.</li><li>Total current drawing: about 1mA.</li></ol><br />Circuit set-up using oscilloscope and sine wave generator:<br />Connect a 1KHz sine wave generator to J1 and the oscilloscope to J2.<br />Adjust R4 until the output square wave shows equal mark-space ratio.<br /><br />"By ear"<br /><br /><span style="font-weight: bold;">circuit set-up:</span><br /><br />Connect a musical instrument to J1 and an amplifier to J2.<br />Carefully adjust R4 in order to obtain as maximum output sound intensity as possible.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-45279750211651020832009-05-26T19:15:00.000-07:002009-05-26T19:33:42.199-07:00UltraSonic RadarThis is a very interesting project with many practical applications in security and alarm systems for homes, shops and cars. It consists of a set of ultrasonic receiver and transmitter which operate at the same frequency. When something moves in the area covered by the circuit the circuits fine balance is disturbed and the alarm is triggered. The circuit is very sensitive and can be adjusted to reset itself automatically or to stay triggered till it is reset manually after an alarm.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg80CfK1qKKBg1sF0hnyipzV0XxGnthp99DepxxcT3UpYsgWaE4eHTWGMAYvL_GU4Fy5Wek9qNoTeLldS7x7qEN_q-ORDQd32Xtg3pXRSNtmElBdnISHicsu5_CYZJDdYn01mZ_8FqgFnpf/s1600-h/1.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 310px; height: 208px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg80CfK1qKKBg1sF0hnyipzV0XxGnthp99DepxxcT3UpYsgWaE4eHTWGMAYvL_GU4Fy5Wek9qNoTeLldS7x7qEN_q-ORDQd32Xtg3pXRSNtmElBdnISHicsu5_CYZJDdYn01mZ_8FqgFnpf/s400/1.gif" alt="" id="BLOGGER_PHOTO_ID_5340325076982178066" border="0" /></a><br /><span style="font-weight: bold;">How it Works</span><br /><br /> As it has already been stated the circuit consists of an ultrasonic transmitter and a receiver both of which work at the same frequency. They use ultrasonic piezoelectric transducers as output and input devices respectively and their frequency of operation is determined by the particular devices in use.<br /><span class="fullpost"><br /> The transmitter is built around two NAND gates of the four found in IC3 which are used here wired as inverters and in the particular circuit they form a multivibrator the output of which drives the transducer. The trimmer P2 adjusts the output frequency of the transmitter and for greater efficiency it should be made the same as the frequency of resonance of the transducers in use. The receiver similarly uses a transducer to receive the signals that are reflected back to it the output of which is amplified by the transistor TR3, and IC1 which is a 741 op-amp. The output of IC1 is taken to the non inverting input of IC2 the amplification factor of which is adjusted by means of P1. The circuit is adjusted in such a way as to stay in balance as long the same as the output frequency of the transmitter. If there is some movement in the area covered by the ultrasonic emission the signal<br /><br /> that is reflected back to the receiver becomes distorted and the circuit is thrown out of balance. The output of IC2 changes abruptly and the Schmitt trigger circuit which is built around the remaining two gates in IC3 is triggered. This drives the output transistors TR1,2 which in turn give a signal to the alarm system or if there is a relay connected to the circuit, in series with the collector of TR1, it becomes activated. The circuit works from 9-12 VDC and can be used with batteries or a power supply.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgULXXYShvgm-PBkJeZRAApjXtO-hCIZ5ZhKaRbwkG_6kTMgNw2stvpgAe0nRC8JC4iAKKXR6BlDsxYrq0Vgnckm9Gb7tYf7FKwEyGBOdIl501tutiXIYk7fzIiou9E9dWgQ49rWluSI2zS/s1600-h/2.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 228px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgULXXYShvgm-PBkJeZRAApjXtO-hCIZ5ZhKaRbwkG_6kTMgNw2stvpgAe0nRC8JC4iAKKXR6BlDsxYrq0Vgnckm9Gb7tYf7FKwEyGBOdIl501tutiXIYk7fzIiou9E9dWgQ49rWluSI2zS/s400/2.gif" alt="" id="BLOGGER_PHOTO_ID_5340325078119760802" border="0" /></a><br /><span style="font-weight: bold;">Construction</span><br /><br /> First of all let us consider a few basics in building electronic circuits on a printed circuit board. The board is made of a thin insulating material clad with a thin layer of conductive copper that is shaped in such a way as to form the necessary conductors between the various components of the circuit. The use of a properly designed printed circuit board is very desirable as it speeds construction up considerably and reduces the possibility of making errors. Smart Kit boards also come pre-drilled and with the outline of the components and their identification printed on the component side to make construction easier. To protect the board during storage from oxidation and assure it gets to you in perfect condition the copper is tinned during manufacturing and covered with a special varnish that protects it from getting oxidised and also makes soldering easier. Soldering the components to the board is the only way to build your circuit and from the way you do it depends greatly your success or failure. This work is not very difficult and if you stick to a few rules you should have no problems. The soldering iron that you use must be light and its power should not exceed the 25 Watts. The tip should be fine and must be kept clean at all times. For this purpose come very handy specially made sponges that are kept wet and from time to time you can wipe the hot tip on them to remove all the residues that tend to accumulate on it. DO NOT file or sandpaper a dirty or worn out tip. If the tip cannot be cleaned, replace it. There are many different types of solder in the market and you should choose a good quality one that contains the necessary flux in its core, to assure a perfect joint every time. DO NOT use soldering flux apart from that which is already included in your solder. Too much flux can cause many problems and is one of the main causes of circuit malfunction. If nevertheless you have to use extra flux, as it is the case when you have to tin copper wires, clean it very thoroughly after you finish your work. In order to solder a component correctly you should do the following:<br /><br /><ul><li>Clean the component leads with a small piece of emery paper.</li><li>Bend them at the correct distance from the component�s body and insert the component in its place on the board.</li><li>You may find sometimes a component with heavier gauge leads than usual, that are too thick to enter in the holes of the p.c. board.</li><li>In this case use a mini drill to enlarge the holes slightly. Do not make the holes too large as this is going to make soldering difficult afterwards.</li><li>Take the hot iron and place its tip on the component lead while holding the end of the solder wire at the point where the lead emerges from the board. The iron tip must touch the lead slightly above the p.c. board.</li><li>When the solder starts to melt and flow wait till it covers evenly the area around the hole and the flux boils and gets out from underneath the solder. The whole operation should not take more than 5 seconds. Remove the iron and allow the solder to cool naturally without blowing on it or moving the component. If everything was done properly the surface of the joint must have a bright metallic finish and its edges should be smoothly ended on the component lead and the board track. If the solder looks dull, cracked,or has the shape of a blob then you have made a dry joint and you should remove the solder (with a pump, or a solder wick) and redo it.</li><li>Take care not to overheat the tracks as it is very easy to lift them from the board and break them.</li><li>When you are soldering a sensitive component it is good practice to hold the lead from the component side of the board with a pair of long-nose pliers to divert any heat that could possibly damage the component.</li><li>Make sure that you do not use more solder than it is necessary as you are running the risk of short-circuiting adjacent tracks on the board, especially if they are very close together.</li><li>When you finish your work cut off the excess of the component leads and clean the board thoroughly with a suitable solvent to remove all flux residues that may still remain on it.</li><li>There are quite a few components in the circuit and you should be careful to avoid mistakes that will be difficult to trace and repair afterwards. Solder first the pins and the IC sockets and then following if that is possible the parts list the resistors the trimmers and the capacitors paying particular attention to the correct orientation of the electrolytic.</li></ul><br />Solder then the transistors and the diodes taking care not to overheat them during soldering. The transducers should be positioned in such a way as they do not affect each other directly because this will reduce the efficiency of the circuit. When you finish soldering, check your work to make sure that you have done everything properly, and then insert the IC�s in their sockets paying attention to their correct orientation and handling IC3 with great care as it is of the CMOS type and can be damaged quite easily by static discharges. Do not take it out of its aluminium foil wrapper till it is time to insert it in its socket, ground the board and your body to discharge static electricity and then insert the IC carefully in its socket. In the kit you will find a LED and a resistor of 560 � which will help you to make the necessary adjustments to the circuit. Connect the resistor in series with the LED and then connect them between point 9 of the circuit and the positive supply rail (point 1).<br /><br /> Connect the power supply across points 1 (+) and 2 (-) of the p.c. board and put P1 at roughly its middle position. Turn then P2 slowly till the LED lights when you move your fingers slightly in front of the transducers. If you have a frequency counter then you can make a much more accurate adjustment of the circuit. Connect the frequency counter across the transducer and adjust P2 till the frequency of the oscillator is exactly the same as the resonant frequency of the transducer. Adjust then P1 for maximum sensitivity. Connecting together pins 7 & 8 on the p.c. board will make the circuit to stay triggered till it is manually reset after an alarm. This can be very useful if you want to know that there was an attempt to enter in the place which are protected by the radar.<br /><br /><span style="font-weight: bold;">Componets:</span><br /><br />R1 = 180 KOhm<br />R2 = 12 KOhm<br />R3, 8 = 47 KOhm<br />R4 = 3,9 KOhm<br />R5, 6, 16 = 10 KOhm<br />R7, 10, 12, 14, 17 = 100 KΩ <br />R9, 11 = 1 MOhm <br />R13, 15 = 3,3 KOhm<br />C1, 6 = 10uF/16V <br />C2 = 47uF/16V<br />C3 = 4,7 pF<br />C4, 7 = 1 nF<br />C5 = 10nF<br />C8, 11 = 4,7 uF/16<br />C9 = 22uF/16V<br />C10 = 100 nF<br />C12 = 2,2 uF/16V<br />C13 = 3,3nF<br />C14 = 47nF<br />TR1, 2, 3 = BC547 , BC548<br />P1 = 10 KOhm trimmer<br />P2 = 47 KOhm trimmer<br />IC1, 2 = 741 OP-AMP<br />IC3 = 4093 C-MOS<br />R = TRANSDUCER 40KHz<br />T = TRANSDUCER 40KHz<br />D1, 2, 3, 4 = 1N4148</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-85140426006236359512009-05-12T02:27:00.000-07:002009-05-12T02:37:10.149-07:00Port-Powered Temperature MeterThis is a four-channel temperature measurmet adapter that works without external power supply. It will suitable for measureing temperature and logging its data with a PC. The circuit diagram is very simple and no adjustment is required, everybody will able to build it with ease :-)<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjchSdPXZyslZ3vXQ1LbKx3BsgjxTwmyn2B98TGFY4DSBPlsI_okT4SEvCu3ls4PaZ7uCr5j9ssGSipQ9oZmNHJAT0JEFXMqfp7t4lPm_0Xfusyv83VDDQANONPB8nJ4MIbHmyB3myi1siA/s1600-h/3.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 251px; height: 190px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjchSdPXZyslZ3vXQ1LbKx3BsgjxTwmyn2B98TGFY4DSBPlsI_okT4SEvCu3ls4PaZ7uCr5j9ssGSipQ9oZmNHJAT0JEFXMqfp7t4lPm_0Xfusyv83VDDQANONPB8nJ4MIbHmyB3myi1siA/s400/3.jpeg" alt="" id="BLOGGER_PHOTO_ID_5334868905983620226" border="0" /></a><br />Specs. Micro-controller ATtiny15L (Atmel)<br />Number of channels Four channels<br />Measurement Range -40°C to +105°C (0.1°C/step)<br />or raw A-D value<br />Measurement Error ±0.5°C (at room temperature)<br />Sensor 103AT (Semitec)<br />Power Supply Supplyed from COM port (typ. 5mA)<br />Cost Approx. 1200JPY (All parts)<br /><span class="fullpost"><br /><span style="font-weight: bold;">HARDWARE</span><br /><br /><span style="font-weight: bold;">Micro-controller</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8yNviTE3sG4_DDBr5ixktvreGUreF_juLp0vhNwN0ldJHzExbqjN4g6Y9GF8DtU_dE56KMeKoa4iGcbw4EpFdOZtBgJ4CD6bg7U59ojTt6O9KQ-j-upRsrGeNFN2wRI4IG-DJw-5XYj79/s1600-h/4.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 183px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8yNviTE3sG4_DDBr5ixktvreGUreF_juLp0vhNwN0ldJHzExbqjN4g6Y9GF8DtU_dE56KMeKoa4iGcbw4EpFdOZtBgJ4CD6bg7U59ojTt6O9KQ-j-upRsrGeNFN2wRI4IG-DJw-5XYj79/s400/4.png" alt="" id="BLOGGER_PHOTO_ID_5334868907349892882" border="0" /></a>I chose an Atmel ATtiny15L for this project. It is the only device that has a built-in 10bit A-D converter in the 8 pin AVRs. The A-D converter has a bandgap reference and differencial amplifire as its front-end. The AVR core is clocked by only internal RC oscillator (calibrated to 1.6MHz), any other clock souce cannot be used. Also 25.6MHz clock source that 16x multiplied from core clock is available for timer/counter. This means that a fast PWM output can be generated. Therefore the ATtiny15L has good analog I/O capabiltity.<br /><br />In this project, the A-D converter is used as four channels, single-ended, no gain and VREF from Vcc configuration. However RSTDISBL fuse must be programmed in order to use pin #1 as one of the analog inputs, an AVR programmer that can program in HVS mode is required.<br /><br /><span style="font-weight: bold;">Power Supply</span><br /><br />The devices that works on the COM port without external power supply, such as serial mouse, are powered from the COM port. When an application program opens COM port, ER and RS signals will go high. The high level voltage is from 6V to 12V at most PCs, and it can supply 5mA at least. This is sufficient for low power micro-controllers.<br /><br /><span style="font-weight: bold;">Sensors</span><br /><br />Four 103AT precision thermisters are used as temperature sensor. Its variation is very small, its temperature - resistance error at room temperature is ±0.3°C. The error of series resisters should be within ±0.5% to enable calibration-free design.<br /><br /><span style="font-weight: bold;">FIRMWARE</span><br /><br />The program only respond the values of each channel to the PC by trigger command. The temperature - resistance curve of the thermister is not linear so that the raw A-D value is linearlized and converted to temperature value in software process. When replace the thermister with any oters, the linearlization table in the source code must be re-built. The raw A-D value can also be read, it will be used as voltage meter.<br /><br />The trigger command is one "T" or "R" character, returened results are the temperarute for "T" command, raw A-D value for "R" command. Each value is separated by a comma and terminated by a <crlf>.<br /><br /><a href="http://elm-chan.org/works/temp4/temp4src.zip">Free Firmware</a><br /></crlf></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-24912870912633447812009-05-11T23:22:00.000-07:002009-05-12T00:19:54.960-07:00Digital Capacitance MeterThis is a simple capacitance meter which can measure capacitance value easy. There are some measurement methods for capacitance, at one time the capacitance was measured with a impedance bridge or a dip meter. Recently typical capacitance meters can measure capacitance and some additional characteristics from current vector by applying AC voltage to the Cx. Some simple capacitance meter use integration method that measureing transient response of the R-C network. There are some construction kits based on this method.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUwB87vUtBf35BUiPlaXGmnVE4qT-0Y5O8vhxjHL7rWfzVN1KsWCbmioaxdR6pCAxRmYtdqc-SU2UO5qMrFlItoNpvmZf4sSr9EiJ9EgFcsuxcogQlBdj3jbhwxgE7170swp2FFteZnYo2/s1600-h/2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 342px; height: 265px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUwB87vUtBf35BUiPlaXGmnVE4qT-0Y5O8vhxjHL7rWfzVN1KsWCbmioaxdR6pCAxRmYtdqc-SU2UO5qMrFlItoNpvmZf4sSr9EiJ9EgFcsuxcogQlBdj3jbhwxgE7170swp2FFteZnYo2/s400/2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5334830726926170354" border="0" /></a><br />This project uses the integration method. There is an advantage that the resulut can be got as a digital data directly because it bases measurement of time, accurate analog circuit is not required and its calibration can be done easy by using a micro controller. Therefor the integration method is suitable for hand built capacitance meter with high realizability.<span class="fullpost"><br /><br /><span style="font-weight: bold;">Hardware</span><br /><br />To measure a charge time, only a voltage comparator, a counter and some glue logics are needed. However, a microcntroller (AT90S2313) is used for this project to realize the system easy. In point of fact, I had thought that analog comparator in the AVR is not useful. But I found that the compare output can also be used as a captureing trigger of TC1. This is a nice feature for that use :-)<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAn7zcVwvFTSHmDsjMduGylQ_-tk7psAr_jddjbJTI2GeZ0phB3tmrCYV_t2EaIhWP1F2qN-0pPm1RFIHD47AJob6KyPdvuQO7INuTUDBVNutC8x2SpjhxJKpZlDKmLJF3d0Velzhyphenhypheng2Bh/s1600-h/1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 239px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAn7zcVwvFTSHmDsjMduGylQ_-tk7psAr_jddjbJTI2GeZ0phB3tmrCYV_t2EaIhWP1F2qN-0pPm1RFIHD47AJob6KyPdvuQO7INuTUDBVNutC8x2SpjhxJKpZlDKmLJF3d0Velzhyphenhypheng2Bh/s400/1.png" alt="" id="BLOGGER_PHOTO_ID_5334830723837945298" border="0" /></a>The integration circuit can be simplified like shown in the circuit diagram. The threshold voltage is generated by divider registers. It seems not stable to valiation of supply voltage however the charge time is not affected by the supply voltage. You will able to find that voltage terms can be erased when apply formure 2, VC1/E term is dtermined by only divide ratio. This advantage is the essence found in the NE555 timer IC. Ofcourse the supply voltage must be steady during integration.<br /><br />According to the foundation, measure integration time with only one threshold voltage will do. However input voltage of near ground level is little difficult to use due to following reasons.<br /><br /><ul><li> Voltage not drop to 0 volt. Capacitor voltage will not be discharged to zero volt. It require a time to discharge capacitor to sufficientaly low voltage for measuring operation. It will expand measureing interval. Saturation voltage at discharge switch is also increase this effect.</li><li> There is a time beween start to charge and then start timer. It will cause a measurement error. This can be ignored on the AVR because it requires only one clock cycle for that sequence. Any other microcontroller may rquire to consider this problem.</li><li> Leakage current on analog input. Accrding to AVR data sheet, the leakage current on analog input is increased near zero volt. This will cause a measurement error. </li></ul><br />To avoid to use near zero volt, two threshold voltages VC1(0.17 Vcc) and VC2(0.5 Vcc) are used and measure t2-t1(0.5RC). This can avoid avobe problems and comparator delay/offset will also be canceled. As for the leakage currnet, circuit board should be kept clean to minimize surface leak.<br /><br />The supply voltage is generated with a DC-DC converter powered from a 1.5V AA cell. The swiching power supply is not suitable for measurement circuit but it seems not affected by ripple voltage because two ripple filters are applied. I recommend to use a 9V 6LR61 battery and a 78L05 instead, and do not omit BOD or you will be afflicted with EEPROM data collaption.<br />Calibration<br /><br />When power is on first time, full segment, "E4" and ten several pF will be displayed. This value means stray capacitance on the circuit. The stray capacitance can be canceled by SW1. Two reference capacitors of 1nF and 100nF are needed to calibrate the capacitance meter. If you could not obtain the reference capacitors, accurate capacitors within ±1% can be used insted. This capacitance meter does not have any trimmer pot, it performs the calibration by reading the reference capacitor and saving gain adjustment value in full automatic operation.<br /><br />To calibrate low range: First, adjust zero with SW1. Next, tie pin #1 and #3 of connector P1, set a 1nF reference capacitor and push SW1.<br /><br />To calibrate high range: Tie pin #4 and #6 of connector P1, set a 100nF reference capacitor and push SW1.<br /><br />"E4" at power on means calibration value in the EEPROM has been broken. It will never be displayed if once calibration is performed. As for zero adjustment, it is not saved into the EEPROM, it will require each time power-on or any jig is attached.<br /><br /><a href="http://elm-chan.org/works/cmc/cmcsrc.zip">Free Firmware</a><br /><br /></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-78123138827430505852009-05-10T19:10:00.000-07:002009-05-10T19:36:28.495-07:00Radio Spectrum MonitorThis is an experimental work to monitor a spectrum pattern in radio band, and is a continuous project from Audio Spectrum Monitor. To analyze the spectrum of an input signal, I chose an Atmel AVR micro controller that used in the Audio Spectrum Monitor to process FFT. When think it easy, it can be thought that sample an input RF signal directly and analyze it will do. However, you will able to recognize that there are some technical difficulties from following reasons.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAjLwOY6n2x2FcAQ3EhdcdHpCKOWy0d849DlSrtxu1FgUIStapFLbwpw9OsNSfNtah8DBJ12NZ0gi_GH3gn80wyYrw0eVsoDBSf1jIb5l2Kfav6GPmBge5ZGUH-kX_OLBrSrPYmwbMcJt1/s1600-h/5.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 235px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAjLwOY6n2x2FcAQ3EhdcdHpCKOWy0d849DlSrtxu1FgUIStapFLbwpw9OsNSfNtah8DBJ12NZ0gi_GH3gn80wyYrw0eVsoDBSf1jIb5l2Kfav6GPmBge5ZGUH-kX_OLBrSrPYmwbMcJt1/s400/5.jpeg" alt="" id="BLOGGER_PHOTO_ID_5334387264514629394" border="0" /></a><br /><ol><li> The acquisition unit must have a sufficient speed and accuracy that covering over the radio frequency range. As for AM radio band like this project, fast 12 bit ADC and specific controller will able to cover this range. However there is no proper ADC for UHF band.</li><li> Number of samples to meet required frequency resolution, fSAMP/fFUND samples, becomes too large. When monitor an AM radio band around 1 MHz in frequency resolution of 500 Hz, over 4000 samples will be required at least. And when monitor a VHF band in same frequency resolution, how many samples will be required...</li></ol><br /><span class="fullpost"><br />To solve this difficulties, there is a generic method called Frequency Conversion. In brief, down-convert the RF signal to lower frequency with a mixer (multiplyer) before sampling stage. When process the signals as complex signal for the frequency conversion, it can handle negative frequency, and the center frequency can be moved to zero hertz without interference by image signals. This means that the sampling frequency higher than span frequency range will do. When monitor a 100 MHz band in span of ±1 MHz, it will be converted down to 0±1 MHz and sampled it in only 2 Msps. You may able to understand easy when explain it as `cut and paste' on the frequency domain. Actually, this kind of radio spectrum monitors are being supplied from some radio equipment vendors.<br /><br /><span style="font-weight: bold;">Hardware</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhegDuHxvOJp03bMp9iL1t-775x95H3LfBf_RbcaxyMCDtPrtl0c6dDLVdG4TsYXF_8LRvK6ZIQ56kQDtBMTI7U0UnNca9bFC4g2qs7Z3tWsVz42o21z7GN42QmRgRNOCkoTeEIpyVSv972/s1600-h/4.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhegDuHxvOJp03bMp9iL1t-775x95H3LfBf_RbcaxyMCDtPrtl0c6dDLVdG4TsYXF_8LRvK6ZIQ56kQDtBMTI7U0UnNca9bFC4g2qs7Z3tWsVz42o21z7GN42QmRgRNOCkoTeEIpyVSv972/s400/4.png" alt="" id="BLOGGER_PHOTO_ID_5334387261588708322" border="0" /></a>In this project, an intermediate frequency signal from mixer output of an AM radio (fC=455kHz) is used as an input signal. It is converted again down to zero hertz in complex signal, so that the signal path, mixer and local oscillator, must be composed for complex signal processing. The complex signal is expressed in two wire IQ signal, the real part corresponds to I signal and the imaginary part corresponds to Q signal. The arithmetic circuits for IQ signal are realized in method of complex arithmetic. For example, a mixing circuit for IQ signals requires four multipliers and two adders from the formula:<br /><br /><div style="text-align: center; font-weight: bold;">(a1+jb1)(a2+jb2) = (a1a2-b1b2)+j(a1b2+a2b1)<br /></div><br />Therefore the analog process of IQ signal requires large scale circuit compared to real signal process, so that the IQ signal is usually digitized after minimal analog process and following process are done in digital processor. In case of one input is real, only two multiplyer will do. By the way, when view a real signal as a complex signal, its spectrum pattern of positive part and negative part is line symmetrical. Real signal can be saied that the imaginary part is always zero. The case of complex signal becomes such state is: there are conjugate complex numbers, changed sign of the imaginary part (changed sign of frequency), for each complex frequency components. Therefore the real signal has symmetrical spectrum around the origin.<br /><br /><span style="font-weight: bold;">Software</span><br /><br />The firmware samples IQ signal, analyze it in FFT algorithm and draw spectrum pattern into LCD module. These processes are done in refresh rate of approximately 60 times per second. IQ signal is sampled 128 points in samplig rate of 64 ksps at a time, span frequency of ±32 kHz around local frequency (455 kHz) can be monitored. Now horizontal scale (frequency) is labeled on the LCD but when measure local frequency of the radio receiver, the tuned frequency will able to be displayed under the spectrum bars - I became aware this idea during writing this document and implemented it in a hurry:-) When a local input from receiver is valid, frequency scale is appered in the LCD and tuned frequency is refrected.<br /><br />The fast FFT routine is copied from audio spectrm monitor as is. Basically, FFT algorithm is in complex input/output, it can be used for complex signal with no modification unless it is optimized for real input. When input is a real signal, only half of result is valid because it is symmetrical around the origin. Ofcourse each domain of output is valid when input is a complex signal.<br /><br />When apply a power, a menu window will apper and can be set working condition with a joystick. Each item can be selected with up/down action, changed with right action and enter running mode with push action. In running mode, up action hold/resume display, down action resets peak hold (if selected), left action redo automatic null (offset cancellation of ADC input) and push action returns to menu. Window function can also be selected, you will able to recognize difference between each window. Wave form mode monitors raw IQ signal but it will not useless.<br /><br /><a href="http://elm-chan.org/works/rsm/rsm.zip">Free Firmware</a><br /><br /><span style="font-weight: bold;">Adjustment</span><br /><br /><ol><li> Adjust local frequency to 455 kHz with TC1.</li><li> Apply 455+10 kHz, 100mVP-P sin wave to the input port and set I and Q signal as same amplitude and quadrature phase at ADC input with VR1 and VR2. And confirm that DC levels are Vcc/2 (a little offset is negligible) and no distortion is recognized.</li><li> Enter running mode. When a spectrum bar is 20 bins right from center, it is working successfully. If an image is appering at opposite position, adjust VR1 and VR2 to eliminate it carefully. A peak appearing center at start is due to left DC offset of IQ signal, it will be nulled automatically.</li></ol><br />An AM super heterodyne radio receiver is used as a signal source. It may be modified to export mixer output and local oscillator output (this can be ommited). When it is a transister radio, large local frequency component (tuned freqency + IF) will pass through the mixer due to the mixer will be cheap emitter injection type. This affects dynamic range of DBM input, so that unnecessary signals above IF must be filtered out with a LPF. When IF frequency of radio receiver is 450 kHz, please read "455" in this page to "450".</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-2283234267347806172009-05-10T18:47:00.000-07:002009-05-10T18:58:01.447-07:00GPS Data LoggerI have got a GPS module last year and I built a GPS data logger that records position data from the GPS module. The position data is output in NMEA-0183 format and store its sentence into any storage device. The position data can be processed with existing GPS utilities for interesting applications, such as Tracing the route on Google Maps (HTML source text).<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQaByUZpNwguY9eWOGJpjxrG_Yw6EXTtimf_1Ic_Bj9Ma-NortoW8Lp3VXRhZDhLo8wvsVdIsMYbok4_pPMyw7S_0E9qZq7LTp5Of-i8Iv00I6DgKs37RM2ZeBc0HtyiongIMw7vy4AG3x/s1600-h/1.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 237px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQaByUZpNwguY9eWOGJpjxrG_Yw6EXTtimf_1Ic_Bj9Ma-NortoW8Lp3VXRhZDhLo8wvsVdIsMYbok4_pPMyw7S_0E9qZq7LTp5Of-i8Iv00I6DgKs37RM2ZeBc0HtyiongIMw7vy4AG3x/s400/1.jpeg" alt="" id="BLOGGER_PHOTO_ID_5334379387341639154" border="0" /></a><span class="fullpost"><br /><br /><span style="font-weight: bold;">Hardware</span><br /><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWPmVsfuRsfg4vySDHdk2VqOtQnRqbUmhhScPKasL9IMx2Fan9rTjDohTog42QiJxFAPON2SqG0CaYdRRhBck5XHCKxWcF9-JHjOE-g0OZ3kW03Q359k6dD4U8qEM0xkRKAAaKjm2MeIUh/s1600-h/1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWPmVsfuRsfg4vySDHdk2VqOtQnRqbUmhhScPKasL9IMx2Fan9rTjDohTog42QiJxFAPON2SqG0CaYdRRhBck5XHCKxWcF9-JHjOE-g0OZ3kW03Q359k6dD4U8qEM0xkRKAAaKjm2MeIUh/s400/1.png" alt="" id="BLOGGER_PHOTO_ID_5334379394625653106" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxtRrid4JJ-oQJZ-KqcufhVQlzem8R44AwYK8OuyhfkiRilz4ggWxKWKBAtCIoQGMJnFB0n4wCko7xHgWChohE9-nAPOKJ9CwaaKKyhflaFy55KLPUjMvRkv9N3I0dXwa8zlUjL-pLUeQC/s1600-h/2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 277px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxtRrid4JJ-oQJZ-KqcufhVQlzem8R44AwYK8OuyhfkiRilz4ggWxKWKBAtCIoQGMJnFB0n4wCko7xHgWChohE9-nAPOKJ9CwaaKKyhflaFy55KLPUjMvRkv9N3I0dXwa8zlUjL-pLUeQC/s400/2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5334379390928762562" border="0" /></a><br />This is the inside of the built data logger and the circuit diagram. To store the tracking log, MMC/SDC is used for the recording media. The MMC/SDC is the most suitable purpose to collect the logged data to the PC. The GPS data logger is mainly used on automobile, so that its power supply circuit should pass the load dump surge immunity test. The operating power is got from only ACC line for good usability, and power switch is ommited. To detect brown-out and power-off, input supply voltage is monitored with the microcntroller. The controller part works at 3.0 volts and the GPS module works at 5.0 votls are tied via a level converters each other.<br /><br /><span style="font-weight: bold;">Software</span><br /><br />When a positioning is established and a valid RMC sentence is detected, logging operation is started with a log file named in current UTC time YYMMDD.log. When same name is already existing, it starts to store from end of the file.<br /><br />Because the operating power is got from ACC line, power-off will occure asynchronously regardless of the operating state. When power-off is occured, open file in write mode must be closed quickly during operating power is retaining in the capacitor, or the log file will be lost. In this project, when supply voltage is continuously below 8.0 volts for 10 milliseconds, it reecognizes that power-off and close the log file.<br /><br /><a href="http://elm-chan.org/works/glg/glg.zip">Free Firmware</a></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-48984284570153215962009-05-07T23:03:00.000-07:002009-05-07T23:15:09.754-07:00Graphic MP3 PlayerThe MP3 players consist of only semiconductor parts and no complex mechanics. This is a great feature for electronics handicrafts because it can be built easy with the same performance as commercial products except for the appearance. After a long blank in MP3 project, I built a new one again as the second MP3 project.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9ewnQ-Nsxe-BcQx40a38GhIy-1-SL9WG8tgPjywK-0THM1Uo6tDUsMCQfC3NKrLcFJ4pVaUe_7KHpbOucZOy-FRjU3DD3Xnwm4DdKmj0T-MXZvpZCHa41t96ouS608lyjifhToaf9fIih/s1600-h/8.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 325px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9ewnQ-Nsxe-BcQx40a38GhIy-1-SL9WG8tgPjywK-0THM1Uo6tDUsMCQfC3NKrLcFJ4pVaUe_7KHpbOucZOy-FRjU3DD3Xnwm4DdKmj0T-MXZvpZCHa41t96ouS608lyjifhToaf9fIih/s400/8.jpeg" alt="" id="BLOGGER_PHOTO_ID_5333332293315150386" border="0" /></a><br />The first MP3 project was Pocket sized MP3 Player built with an MP3 chipset that obtained by chance. I have completed some projects of MP3 application for my business but not for hobby because I have no practice of listening music at the outdoors. Why did I built it in pocket size? Because that was only an impulse and nothing else. BTW, the MP3 player is being used in my car as a car MP3 player :-)<br /><span class="fullpost"><br />Now, there are many easy-to-use MP3 decoders that integrates DSP, DAC and amplifier on a chip. As the result, the MP3 player becomes to a popular project for electronics handiworks and everybody is enjoying to build it as their original project. One day I got to want to build an MP3 player by a reason (described below) and decided to start a new project. This is a regular project on the MP3 player after 8 years. I designed it as a desktop player because portable player is not useful for me.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirKCLsxFQmbjCMRYZ6koBQw4meUxN_mQuPeZaAKBaHCXRZM8Z7QFkCAVzK-sxzQC4AkJtHWBoXkYaz73mwd2HwF65beazdZWKepT19QSZeTHdaCOx7-NGEeBYQc1BZolTS9L9Mo3Cis9gK/s1600-h/7.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirKCLsxFQmbjCMRYZ6koBQw4meUxN_mQuPeZaAKBaHCXRZM8Z7QFkCAVzK-sxzQC4AkJtHWBoXkYaz73mwd2HwF65beazdZWKepT19QSZeTHdaCOx7-NGEeBYQc1BZolTS9L9Mo3Cis9gK/s400/7.jpeg" alt="" id="BLOGGER_PHOTO_ID_5333332288046961826" border="0" /></a><br /><span style="font-weight: bold;">Hardware</span><br /><br />Below image shows the block diagram and the circuit diagram of built MP3 player. It has a feature that it has a large color LCD and a touch screen. Followings describe on each block.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuHq2dXBiC2phHsfQJAsGkC2jmzRKIYZyVzj2u79hYrwCF1gpUUeID18xxYWdFhumhEsIdKVim7sifvXXbEBKREBoa09btpyyIH_y4MdzPhKqHqflE1TQiHISwo6mXJedsz0JEtAvKtRDt/s1600-h/5.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 264px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuHq2dXBiC2phHsfQJAsGkC2jmzRKIYZyVzj2u79hYrwCF1gpUUeID18xxYWdFhumhEsIdKVim7sifvXXbEBKREBoa09btpyyIH_y4MdzPhKqHqflE1TQiHISwo6mXJedsz0JEtAvKtRDt/s400/5.png" alt="" id="BLOGGER_PHOTO_ID_5333332280417032898" border="0" /></a><br /><span style="font-weight: bold;">Controller</span><br /><br />A V850ES/JG2 (NEC Electronics) is used for system control. This is a 32-bit RISC microcontroller with 256KB flash and 24KB RAM. It was not that well known for electronics handiworks but somebody will be interesting in it because the V850 board was bundled as supplement of magazine in this year. For ordinary MP3 players, most 8-bit microcontroller is sufficient to build it. However this project requires a microcontroller with external memory interface because the controller must handle large amount of image data. Of course any popular microcontrollers, such as Renesas SH2 and H8, will able to be used as well. The reason why I chose the V850 is from its very low power consumption and the serial interface is easy-to-use better than Renesas's one. The V850ES/JG2 can run at 20 MHz but it is used at 14.7 MHz (4xPLL from 3.68 MHz xtal) to deliver a clock signal to MP3 decoder and LCDC.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjiAc7SDrX6wWNfjU38DUT13aLpH5o9A4FVgjbcgjm2kwVJ7xqlBUp2nfnLLUw4afl6kNW2RuBDlA-m89peXlxQef1rDP2CcJmTpbogsO7nnUx_ieyqG4sQ8-nqCRRXxSAojY16YeIgkSH/s1600-h/6.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 260px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjiAc7SDrX6wWNfjU38DUT13aLpH5o9A4FVgjbcgjm2kwVJ7xqlBUp2nfnLLUw4afl6kNW2RuBDlA-m89peXlxQef1rDP2CcJmTpbogsO7nnUx_ieyqG4sQ8-nqCRRXxSAojY16YeIgkSH/s400/6.png" alt="" id="BLOGGER_PHOTO_ID_5333332283752820818" border="0" /></a><span style="font-weight: bold;">Storage Media</span><br /><br />SD Memory Card is the de facto standard of flash memory card. It can be attached to the microcontroller via a few signal lines. FAT format is used to store data files in it so that the project using the memory card must implement the FAT file system. Fortunately, there are various FAT libraries on the web as freeware so that everybody can use the memory card in their project with ease.<br /><br /><span style="font-weight: bold;">LCD Module</span><br /><br />A 4″ color STN-LCD module in resolution of 320x240 is used for the display. Recently the price of color TFT-LCD are going falling and color STN-LCD will soon be shut out of the market. This project was started to to use this LCD module before it decays in the junk box.<br /><br />A touch screen is attached on the LCD module, so that command buttons can be omitted. A CCFL is used for the back light and a CCFL inverter is required to drive the back light.<br /><br /><span style="font-weight: bold;">LCD Controller</span><br /><br />The LCD module in this degree of resolution with built-in display buffer is not available and it must be refreshed by external circuit like CRT display system. Therefor it requires an additional LCD controller on the board to drive the graphic LCD module. The display buffer (RAM) is integrated in the LCDC or attached externally. In this project, an S1D13705 (EPSON) is used for LCD control. The S1D13705 has 80KB integrated display buffer and it can display in resolution of 320 by 240 with 8-bit color depth (256/4096 indexed color). It can be attached to the host controller via a 16-bit SRAM like interface.<br /><br />The LCD module requires a 3.3V logic supply and an LCD bias supply (21-25V/3mA). Generally, the contrast of the STN-LCD in high drive duty ratio is affected by ambient temperature, so that a contrast dial is required to adjust the contrast. The contrast dial varies the LCD bias voltage. In this project, the contrast is adjusted automatically in software with a thermister put on the LCD module and a D-A converter.<br /><br /><span style="font-weight: bold;">MP3 Decoder</span><br /><br />Recently VS10xx family (VLSI Solutions) is used for most home-built MP3 projects because it is easy to obtain and use. The VS10xx is designed for portable audio equipments and can drive a headphone directly. However it has only analog outputs and no digital (I2S) output, so that the VS10xx is not good when require an I2S output to attach an external DAC besides the analog performance is not good for Hi-Fi audio.<br /><br />I chose STA013 (ST Microelectronics) for MP3 decoding. The STA013 have been released at the dawn of the MP3 format and widely used as a well known MP3 decoder chip. It has only digital (I2S) output, so that a proper audio DAC is required. This is an advantage on electronic handiworks because it can use various DAC chips and output audio data in SPDIF format with DAI encoder.<br /><br />The STA013 has an integrated PLL oscillator to generate an audio timing clock (384fs) depends on DSP clock. If there is a jitter on the sampling clock, SNR of the analog output will be worse especially on Sigma-Delta DAC. Therefore the PLL power should be tightly filtered and pay attention to parts layout around the loop filter.<br /><br /><span style="font-weight: bold;">Analog Block</span><br />A PCM1748KE (BurrBrown) is used. The analog performance on the data sheet is not so bad but it is a little difficult to achieve expected performance because it is a Sigma-Delta DAC.<br /><br />A post-filter is required at DAC output but only a slow roll-off one will do due to integrated 8x over sampling digital filter. In this circuit, the DAC output is filtered with a LPF+buffer and then output it as a line output and there is no speaker out. Therefore the MP3 player is used with any audio power amplifier.<br /><br />The line output is tied to ADC input of the microcontroller. This is to get amplitude of the line output and display it as a level meter on the LCD. Generally an envelope detector is used for the audio level meter. In this project, to eliminate the envelope detector, the microcontroller samples waveform in sampling rate of 1kHz and detects peak-to-peak value from 20 samples. There will be dip points on the frequency response but there is no problem because this is for only a visual effect.<br /><br /><span style="font-weight: bold;">Building the MP3 Player</span><br /><br />The circuit board must be embedded into a space in height of 10mm, so that the allowable height of the components on the circuit board is less than 6mm. Most of components used in this project ware surface mounted device. They are mounted on the proto-board directly and wired with UEW. This method requires soldering skill and practices but there is an advantage that it can achieve the density of double layered PCB or more. The FPC connector (0.5mm) easily creates solder bridge due to its terminal forms, so that solder the wire to the terminal via a stripe PCB instead of solder the wire directly.<br /><br />The built circuit board is embedded with the LCD module into the case. The case is a clear acrylic case SK-16 (110x78x32mm) sold from Akizuki. Its depth was too long for this project, so that I cut down it to 25mm, paint black from inside and put an aluminum sheet for electromagnetic shield.<br /><br /><a href="http://elm-chan.org/works/gmp/gmp.zip"><span style="font-weight: bold;">Free FirmWare</span></a></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-30690263309304068332009-05-07T18:44:00.000-07:002009-05-07T20:01:58.082-07:00YUV(YCbCr) to RGB converterRecently, most digital video equipments, such as video recorder, DVD player and TV game, have component video output. The component video signal is like RGB video signal, but it cannot connect to RGB monitor directly. Thus I designed and built YUV(YCrCb) to RGB converter to use old TV monitor or video equipment which does not have component video input.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWGCDwsVmHzoDxSnpoJcFCZ3v9fB9FOSBEnNgZH9HT7Tk_XWf_ju7vdMBM_u6N39pNR2q8OJsPhlwIesvoPRP-ViBl0wMShUj5qVgSuASi_AWKywEVSbA35DCChwEXPiRTYLo74nqvQ0s1/s1600-h/1.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 334px; height: 282px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWGCDwsVmHzoDxSnpoJcFCZ3v9fB9FOSBEnNgZH9HT7Tk_XWf_ju7vdMBM_u6N39pNR2q8OJsPhlwIesvoPRP-ViBl0wMShUj5qVgSuASi_AWKywEVSbA35DCChwEXPiRTYLo74nqvQ0s1/s400/1.jpeg" alt="" id="BLOGGER_PHOTO_ID_5333281316586916466" border="0" /></a><br />For old RGB monitor....no, my principal aim is to generate RGB signal from component signal from PlayStation 2 for scan converter because recent shipped PlayStation 2 fixes configuration of video output format to component video when used as DVD player :-( Converting the component signal into RGB signal can enjoy the game and DVD with high quality picture. However, the PlayStation 2 can be fixed to RGB output configuration with only a jumper wire. If you wish to get only RGB signal from the PlayStation 2, I recommend this way instead :-)<span class="fullpost"><br /><br /><span style="font-weight: bold;">The theory of RGB to YUV conversion</span><br /><br />The component video signals are generated by separating a luminance component and two chrominance components from RGB signals with following formulae:<br /><br />Y = 0.299R + 0.587G + 0.114B Luminance component<br /><br />R-Y = R - (0.299R + 0.587G + 0.114B)<br /> = 0.701R - 0.587G - 0.114B Chrominance component (Red)<br /><br />B-Y = B - (0.299R + 0.587G + 0.114B)<br /> = -0.299R - 0.587G + 0.886B Chrominance component (Blue)<br /><br />Note: These parameters are for SDTV(525/625), not for HDTV(750/1120).<br /><br />G-Y crominaice component can also be generated. However, to restore the RGB signal, Y and two chrominance components will do. The G-Y component contains least chrominance in the three chrominance components so that this term is omitted to minimize conversion error.<br /><br />When restore RGB signals from component signals, following formulae are applied.<br /><br />R = Y + (R-Y)<br />G = Y - 0.51(R-Y) - 0.186(B-Y)<br />B = Y + (B-Y)<br /><br />The contents of component video signal are these three signals, Y, R-Y and B-Y. You will able to understand that these are loss-less conversion. However, in order to reduce overall video signal band-width to be recorded or transmitted, the band-width of chrominance components are reduced and some compression processes are applied. Human eyes are sensitive to luminance but not sensitive to chrominance. The quality of chrominance components, such as band-width, SNR and digitizing resolution, can be reduced compared with luminance component.<br /><br />The chrominance signal levels at the transfer line are normalized to luminance amplitude because it is easy to A-D, D-A conversion and transmittion processes. Following are attenuation ratio for the chrominance signals:<br /><br />Cr = 0.713(R-Y)<br />Cb = 0.564(B-Y)<br /><br />And sync pulse is added to luminance signal as -0.3V pulses. These are the component video signals that is appering at input/output point. Typical signal levels at the interface connector are from -0.3V to +0.7V for luminance signal, ±0.35V for chrominance signals.<br /><br /><span style="font-weight: bold;">Hardware</span><br /><br />To convert component video signals into RGB video signals, the alithmetic circuit composed with some OPAMPs is used. However, only it is not sufficient to build complete set, some glue logics are also required.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlj74Q0w36JDvntLeK5uU3-ut9iMBSBvgW2TeUMlb8V0QwZXx1yGsTDt7In5_l95fqv4akw5mjN-gk8KfK43Ldp64ZYXdPuryPVUqRQiPeO9_KNxjfXyO2iVUYZFAGHYyENYiCxnDEZgLs/s1600-h/2.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlj74Q0w36JDvntLeK5uU3-ut9iMBSBvgW2TeUMlb8V0QwZXx1yGsTDt7In5_l95fqv4akw5mjN-gk8KfK43Ldp64ZYXdPuryPVUqRQiPeO9_KNxjfXyO2iVUYZFAGHYyENYiCxnDEZgLs/s400/2.png" alt="" id="BLOGGER_PHOTO_ID_5333281319010131442" border="0" /></a>Most video signal outputs except some high end equipments are AC coupled, DC restore circuit is needed to video input part. To remove sync pulses added to Y signal, blanking circuit is also required. These function should apply for completed process. The timing generator for the functions is realized with only a CPLD because to realize it with discrete components will be complex. Following images show the generated wave form of blanking pulse and clamping pulse. Top one is Y input, below two are /BLANK and /CLAMP. Left image is near horizontal blanking area, right image is near vertical blanking area.<br /><br /><span style="font-weight: bold;">Relationship of picture quality between component video and its source</span><br /><br />Difference between component video signal and YC video signal is the transfer method of chrominance components.<br /><br />At YC video signal, a color sub-carrier is modulated by two chrominance signals with quadrature balanced modulation, and transferred as a chrominance signal. Therefore, the band-width of chrominance signals are reduced to half of the sub-carrier frequency. At NTSC video format, I,Q signal which is shifted 33 degree from R-Y,B-Y axis is used instead of R-Y,B-Y signal, the band-width for I signal is 1.5 MHz, for Q signal is 0.5 MHz. However, most video decoders seem decode in R-Y,B-Y axis and both signals are limited to 0.5 MHz.<br /><br />At component video siglal, two chrominance signals are transferred with two separated lines directly. This is full band-width transmittion. When video signal is from TV game whose source is RGB video buffer, difference between component signal and YC signal appers conspiculusly as some effects shown in following images. In this case, component signal is better than YC signal.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-49360696305505696142009-05-07T01:22:00.000-07:002009-05-07T01:36:47.333-07:00NTSC Test Signal GeneratorA video test pattern generator will be needed when calibrate or test video equipments. To characterize system performance and understand it quantitative, wave form monitor, vector monitor and related video measurement equipments will be required. Some generic patterns, shch as color bars, cross hatch, dots and full field, are also used for home video creation to calibrate video monitors without any measurement equipment.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCxy2Mbch_uaqZFZ1pgawicQPJY5KtURaMhoe8WNK_TsvvEwtXus4944jtOC3k1mgVPusmLnDU-S_brPzDOy10BWTYSAoxlrWoCytKjDo30xP6j1-rlWZ3vR0zfw92zsjA16dYLnhtkC3z/s1600-h/6.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 214px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCxy2Mbch_uaqZFZ1pgawicQPJY5KtURaMhoe8WNK_TsvvEwtXus4944jtOC3k1mgVPusmLnDU-S_brPzDOy10BWTYSAoxlrWoCytKjDo30xP6j1-rlWZ3vR0zfw92zsjA16dYLnhtkC3z/s400/6.jpeg" alt="" id="BLOGGER_PHOTO_ID_5332995684601577282" border="0" /></a><br />This kind of test signal generators for personal use are often found as construction kits, however, most of the kits are designed on cheap analog method and the wave form is not accurate, therefore it cannot be used as a standard signal in fact. I designed and built a digital video test signal generator in order to generate accurate reference signals which can be used for calibration and measurment of video montors and home built video equipments.<span class="fullpost"><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8vxyQZjoqA4lYA50OGEzD1ywwsy_WaPtTtB-qDRZrcw9jRXcLkqKIWy64fG1dP-euDkw8C1J0A9itbYLgIrR4sKECB2_9r9z3U-6J4_cUZymXJRVcGlXzjrEDL0EvHUHXYqmIhUJdYJmL/s1600-h/5.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8vxyQZjoqA4lYA50OGEzD1ywwsy_WaPtTtB-qDRZrcw9jRXcLkqKIWy64fG1dP-euDkw8C1J0A9itbYLgIrR4sKECB2_9r9z3U-6J4_cUZymXJRVcGlXzjrEDL0EvHUHXYqmIhUJdYJmL/s400/5.jpeg" alt="" id="BLOGGER_PHOTO_ID_5332995678117826098" border="0" /></a><br /><br /><span style="font-weight: bold;">Basic Design</span><br /><br /><span style="font-weight: bold;">Supported test patterns</span><br /><br />The test signals used for electronics handiworks are required at least, plus some additional test signals are also implemented. However most test signals are used with wave form monitor, vector monitor, spectrum analyzer and others. An oscilloscope will able to be used instead of the wave form monitor in most case.<br /><br /><span style="font-weight: bold;">Color video signal format</span><br /><br />This signal generator uses a three channel DAC to generate Composite video signal (CVBS) and S video signal (Y/C separated) at the same time, left one channel is not used in NTSC format. It is assigned for one of the color components of Y/CB/CR video format. This feature was not planned some years ago, but it has been added when started to draw the schematic this year, because NTSC television system might be obsoleted in the near future. The two different video format, component video and NTSC video, work in exclusive.<br /><br /><span style="font-weight: bold;">Specifications</span><br /><br />Used LSIs DAC: MB40988 (Fujitsu)<br />MCU: ATmega161 (ATMEL)<br />PLD: XC95108 (Xilinx)<br />Output terminals CVBS: RCA pin jack<br />Y/C: 4pin Mini-DIN (S1)<br />Y/CB/CR: 14pin D type half pitch connector (D2)<br />Output impedance Video out: 75 ohm<br />ID out: 10 kohm<br />NTSC output<br />D1 output (480i) Timing: SMPTE 170M (RS-170A), Setup=0IRE (NTSC-Japan)<br />CVBS output: Y=714mV, Sync=-286mV, Burst=286mVp-p<br />Y/C output: Y=714mV, Sync=-286mV, Burst=286mVp-p<br />Y/CB/CR output: Y=700mV, Sync=-300mV, CB/CR=±350mV<br />D2 output (480p) Timing: SMPTE 293M<br />Y/CB/CR output: Y=700mV, Sync=-300mV, CB/CR=±350mV<br />Sampling 8bit x 3, 28.63636MHz<br />Power Supply AC100V 50/60Hz, <5w style="font-weight: bold;"><br /><br />Hardware<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnRz-jSJTgGEhjVeqDc2p-SLUdBg6ICxoUK-Td5xSik1ubOnpIRZPsyggyInaTPw2vP2GQtC0CDJAEK6zKg9p4WlQ6MtdqrUaLdWWYAqNkIVVR0gqz0d56BtPl3W7eCy43W2l4mAfqnxI6/s1600-h/3.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnRz-jSJTgGEhjVeqDc2p-SLUdBg6ICxoUK-Td5xSik1ubOnpIRZPsyggyInaTPw2vP2GQtC0CDJAEK6zKg9p4WlQ6MtdqrUaLdWWYAqNkIVVR0gqz0d56BtPl3W7eCy43W2l4mAfqnxI6/s400/3.png" alt="" id="BLOGGER_PHOTO_ID_5332996902618498274" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHzaA9s4ejlzEf0afeoZqiY4O-VQu3dgikTia3rsEuJShI8bqqVWtwQWO-2QUUvFvqz-9ql1tJonP4moihh6ZNUVx_tmwtV4jnKYt23DBZS5q0mRu9J1UfCcIJ-6kvNlr5bzXXnXGMSxYZ/s1600-h/4.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 187px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHzaA9s4ejlzEf0afeoZqiY4O-VQu3dgikTia3rsEuJShI8bqqVWtwQWO-2QUUvFvqz-9ql1tJonP4moihh6ZNUVx_tmwtV4jnKYt23DBZS5q0mRu9J1UfCcIJ-6kvNlr5bzXXnXGMSxYZ/s400/4.png" alt="" id="BLOGGER_PHOTO_ID_5332996907887843570" border="0" /></a><span style="font-style: italic;">Genarating a video signal</span><br /><br />To generate any video signal, generic frame memory architecture will be used at most case. All samples of the video frame are stored into the frame memory and they are read in sequence and fed to video DAC. The difference between video signal generator and PC's video system is: which is stored into the frame memory, whole wave form including blanking/sync pattern or only pixel values in visible area.<br /><br />The samplig frequency is 4 fsc (approx. 14.3MHz) at least. This is the typical value on the NTSC video system. However when use 4fsc for video measurements, an excellent video filter which has very sharp cut off, flat group delay and aperture effect compensation, is requied. This is very expensive and difficult to obtain. I chose 8 fsc (approx. 28.6MHz) for this project in order to decrease requirement to the post filter, like over sampling technic.<br /><br /><span style="font-style: italic;">Wave form memory</span><br /><br />The frame memory size is number of samples per line * number of lines per frame. In this case, memory size of 1820 * 525 = 1M samples is required for the frame memory, and the samples must be read out in transfer rate of 8fsc (cycle time of 35 nsec) continualy. An SDRAM is the best for shch use. However I have some small junk SRAMs (32 Kbyte) used for cashe memory, and I wanted to use these chips for the frame memory under recycle spirit :-)<br /><br />To store the test pattern into the small memory, any data compression process is required. I had an eye to a point that the video test signal tend to repeats same line patterns. When store only the line patterns used in the frame and select the required line pattern for each line, the memory size and downloading time will able to be reduced drastically. Ten several line banks will do for the most test patterns except for patterns change vertically, such as picture, monoscope and vertical sweep. Luminance component and chrominance component are separated into two channels. The luma signal has many kind of patterns at vertical blanking area, the chroma signal is fliped every line. The effeciency of compression ratio can be improved when separated the NTSC signal into luma and chroma components. Y/C signal can be generated at the same time.<br /><br />This compression technic can be applied to only NTSC format because the chroma subcarrier at the PAL system, fh*283.75+25 Hz, slips its SC-H phase in rate of 360 degrees per frame, each chroma line patterns in a frame are not the same. SECAM is out of the question. For these video formats, complete frame memory is needed. Don't ask me :-p<br /><br /><span style="font-style: italic;">Controller</span><br /><br />An Atmel ATmega161 is used as controller. It manages user interface, downloading the wave form data to the line memory and selecting wave form for each line under line sequense list. The line patterns are shrinked to 1/2-1/50 based on its monotony of luma and periodicity of chroma, The shrinked data is stored to a serial EEPROM and expanded at downloading, 59 frames (100 Mbytes) are packed into 40 kbytes. Therefore two compression process are applied and attained the total compression ratio of approx. 1/2500.<br /><br /><span style="font-style: italic;">Analog Outputs</span><br /><br />A three channel DAC is used. One channel is assigned for a luma channel, left two channels are for chroma channels. The reason of two DAC channels are assined to chroma is to support Y/CB/CR component output. Of course NTSC mode and component mode cannot be used at the same time. The DAC outputs are filtered, bufferred and then output. CR components placed at inverting input is to compensate frequency response due to aperture effect.<br /><br /><span style="font-style: italic;">Contorl Panel</span><br /><br />Two digits numeric LEDs indicate the frame pattern currently output and one of two video format incicater at the corresponding connector is lit. The frame pattern is selected with a dial and set by clicking the dial. Numeric LEDs blink during the pattern selection.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-80342727637993910392009-05-07T01:03:00.000-07:002009-05-07T01:10:48.599-07:00Video Line SelectorWhen measure video signal with oscilloscope, video line selector is very useful to find a scan line. The line selecter generates trigger pulse at selected line, oscilloscope will display only selected line. This is a very simple video line selector.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicmwyl-xeyuFKUkaBpneJ08D6yU1fofivblQUq7bLHcDThnfm044COChAQPVwvU7Fwvj7HQVrtoTKqA57CokWjt6iq9Ig_ScJb55QtW-VoOGrdLdlLUbCMqmE3QAjagO44IG9FJZhbijds/s1600-h/2.jpeg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 350px; height: 281px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicmwyl-xeyuFKUkaBpneJ08D6yU1fofivblQUq7bLHcDThnfm044COChAQPVwvU7Fwvj7HQVrtoTKqA57CokWjt6iq9Ig_ScJb55QtW-VoOGrdLdlLUbCMqmE3QAjagO44IG9FJZhbijds/s400/2.jpeg" alt="" id="BLOGGER_PHOTO_ID_5332990819128322898" border="0" /></a><br />Now, I have a Tektronix TDS3032B digital oscilloscope for home use. It can also be implemented video line selecter feature with a video module, any external accessory might not be needed. But this project has started before purchasing the new one, so that I achieved the project to open to the public.<span class="fullpost"><br /><br /><span style="font-weight: bold;">Specifications:</span><br />Trigger mode All-line, Both-field, Odd-field, Even-field, An Odd-field in superframe, An Even-field in superframe<br />Control panel Display: 16cols x 1row LCD module<br />Conrol: UP button, DOWN button, MODE button<br />Interface Video input: CVBS/Y Input/Through (75ohms or Hi-Z)<br />Trigger out: TTL level (rise edge)<br />Power supply DC 5..12V, 20mA<br /><br /><span style="font-weight: bold;">HARDWARE</span><br /><br />There are many video line selecter projects from of old, most line selecters are composed with a sync-separator and some counter ICs. In this project, all of counter/trigger function are processed by a microcontroller without external counter. Therefore, the circuit diagram could be very simple and it has many function.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZ6Uf_Z2UC6canqHgLupNCONnhPW486njoWV5ETDz_aFbunrI40vv_UdqxKfMTVfrHaz8p6KULbSCGyLp805aAYKjKHrq32U_SUu0_Qjqs2Ymbu95JI48UYDiSQfa93TF794kqxW1FINPU/s1600-h/1.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZ6Uf_Z2UC6canqHgLupNCONnhPW486njoWV5ETDz_aFbunrI40vv_UdqxKfMTVfrHaz8p6KULbSCGyLp805aAYKjKHrq32U_SUu0_Qjqs2Ymbu95JI48UYDiSQfa93TF794kqxW1FINPU/s400/1.png" alt="" id="BLOGGER_PHOTO_ID_5332990823180497282" border="0" /></a>Compsite sync pulses separated from input video signal are tied to external interrupt of an AVR and a flip-flop. Processing trigger output only software cannot avoid propagation delay and jitter, so that made the trigger edge pass through to the trigger output directly. Sync separator is composed by discrete parts, however, LM1881 is recommended if it is in stock. Test pins are for monitoring the clamped wave form.<br /><br /><span style="font-weight: bold;">SOFTWARE</span><br /><br /><a href="http://elm-chan.org/works/linesel/lssrc.zip">Firmware for NTSC and PAL</a><br /><br />Foreground task processes only user interface. Counting incoming syncs and trigger control are procecced by interrupt driven background tasks. AVR has very high performance, it will able to be implemented some additional functions. Any customized trigger mode or superimposing line marker will easy to implement with modifying the firmware or expanding some external components.<br /><br /><span style="font-style: italic;">Line counting</span><br /><br />First, 16 bit timer/counter is initialized as free running counter with 1.25MHz source clock and compare register is set to 65. The value will reach 79 while a horizontal period. The line counting process is driven by external interrupt (INT1). In this interrupt, when timer/counter has exceeded 60 (3/4H), the timer/counter is cleared and line counter is increased. If timer/counter is less than 60, the interrupt is half-H pulse, the line counter is not updated.<br /><br /><span style="font-style: italic;">Trigger</span><br /><br />After line counter is updated, if the value (next line) matches trigger line, trigger request flag is set. Compare match interrupt (timer/counter maches 65) is occured every 10µs before next line start. In this interrupt, if the trigger request flag is set, reset to external flip-flop is released and next sync edge will pass through the flip-flop. The flip-flop is reset agan by the external interrupt process. The trigger pulse width is approx. 2µs.<br /><br /><span style="font-style: italic;">Detecting vertical sync pulse</span><br /><br />8µs after external interrupt occured, sync level is sampled and stored it into shift register (left shifted). If the interrupt is at half-H, exit with no process. If it is start of line, compare the value of shift register and 0b11111110 (sync pattern at start of vertical sync). Only line 4 in odd field will match this condition. When the vertical sync is detected, set line conter to 4. This process is before updating line counter.<br /><br /><span style="font-style: italic;">Detecting no signal</span><br /><br />If no sync is detected for 20ms, timer/counter overflow interrupt will occure. In this interrupt, no signal flag is set and the condition is informed main task. The no signal flag is cleared by external interrupt (INT1).<br /></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-59099478491042678122009-05-05T01:44:00.000-07:002009-05-05T01:51:36.015-07:00GPIB to RS-232 converterThis project fills the need of anybody who has a test instrument with the GPIB port and likes to get the screen dump on his PC without any GPIB card. It emulates the HP7470A operation on the GPIB side, and outputs the HP-GL data at the RS-232 port to be read and stored on the PC by any suitable software. The operation of this interface is not just limited to plotter emulation: any data intended to be received by a GPIB Device (addressable or listener only) can be captured and brought out to the RS-232 port, including raw data from the instrument or rasterized data for a GPIB graphic printer. GPIB addresses and other set-and-forget parameters can be modified and permanently stored using a simple setup menu. It is based on a PIC16F628A microcontroller, and the PCB size is just 7x7.5cm.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeTt6UUjQ32ZEFs9M_JrsvLv0QbDBC9iDTBdeNn8CdpTmFdXCV0QCcYPBo6k7PP5yhZavYygbu6Ft1dthjL88XFcTckHFQrUVLwJw2H6KTjxZSVUFJ_ydXlCwxz8_mK3qd01thuHwPPF1y/s1600-h/4.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeTt6UUjQ32ZEFs9M_JrsvLv0QbDBC9iDTBdeNn8CdpTmFdXCV0QCcYPBo6k7PP5yhZavYygbu6Ft1dthjL88XFcTckHFQrUVLwJw2H6KTjxZSVUFJ_ydXlCwxz8_mK3qd01thuHwPPF1y/s400/4.jpg" alt="" id="BLOGGER_PHOTO_ID_5332259173393690498" border="0" /></a><br /><span class="fullpost"><br /><span style="font-weight: bold;">SCHEMATIC AND DETAILS</span><br /><br />The hardware of Pic-Plot interface is quite simple: the active components are just a PIC16F628A, a 5V regulator and three transistors. External connections are a GPIB connector, a Serial port and a DC power connector.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7QyNBVFgSNNWOdyzEPIUC3DTDIbfj-tHD0FC-SEOrh039skCP5Ea_s_Qzhn2LnrOhf4Jn-Q0LAUebP54VOrYDP3AVA8e0RP3aCvSeQvYAflhWabLT3MU8psCSku_-0QbbkihufBJU_1dp/s1600-h/7.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 243px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7QyNBVFgSNNWOdyzEPIUC3DTDIbfj-tHD0FC-SEOrh039skCP5Ea_s_Qzhn2LnrOhf4Jn-Q0LAUebP54VOrYDP3AVA8e0RP3aCvSeQvYAflhWabLT3MU8psCSku_-0QbbkihufBJU_1dp/s400/7.JPG" alt="" id="BLOGGER_PHOTO_ID_5332259180897022658" border="0" /></a><br /><br />The microcontroller does all the necessary jobs to emulate GPIB Device functionality, in both Listener and Talker mode, by recognizing addressing, commands and managing the Handshake lines. Controller mode is not needed for the intended functionality, and therefore is not supported. Once the device is addressed and it receives data from the Talker, the same data are forwarded to the COM port at 9600 baud: the hardware UART inside the PIC16F628A generates the serial data going to the PC through the RS232 port. Only in Setup mode the data flow is bidirectional at the same baud rate. The RS-232 connector on the interface is a standard male DB-9, and should be connected to the PC using a null-modem female-to-female serial cable.<br /><br />PCs missing the COM port but equipped with an USB port can be still used with the aid of an inexpensive USB to serial converter, provided that the necessary Virtual Com Port drivers are properly installed.<br /><br />A jumper is provided to enter Setup mode: when Pic-Plot it powered with this jumper in the closed (short) position, then it starts-up in Setup mode. In this mode the microcontroller UART is used to read/change a few set-and-forget parameters. GPIB cable can be left connected to the instrument, but in Setup mode the GPIB port is not monitored by the Pic-Plot. For normal operation this jumper must be left open. More details about Setup mode can be found in the USE AND OPERATION section.<br /><br />Power supply can be any voltage between 8 and 16V, and current drain is far below 20mA. With such a large supply requirements, a low-cost unregulated 12V wall adaptor can be used as a power source. Connector polarity is center positive (+). An interesting possibility for those who use the USB-to-serial bridge is to bypass the Pic-Plot 5V onboard regulator and spill the 5V supply from the USB connector mounted on the bridge. This solution of course asks for a simple modification of the bridge or a modified USB cable, then it is suggested only to people having the necessary technical skills to do things right. You can find details by clicking here, or you might prefer to see our new Pic-plot2 which directly supports GPIB-USB conversion.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoXgo4xEYq2TNH6aSjqZ5w6xqUT_jIsjVHVXs-GG5b69H9_Ks9IK_sW42cJA94ZOQlQ82oKK38uMN27tyNyFcZeCy7olOEYrHwHcHNt61PzjTIDV3c9ZyZ9Y8aENfX69u_Dp7Trrr9J79R/s1600-h/5.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 378px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoXgo4xEYq2TNH6aSjqZ5w6xqUT_jIsjVHVXs-GG5b69H9_Ks9IK_sW42cJA94ZOQlQ82oKK38uMN27tyNyFcZeCy7olOEYrHwHcHNt61PzjTIDV3c9ZyZ9Y8aENfX69u_Dp7Trrr9J79R/s400/5.gif" alt="" id="BLOGGER_PHOTO_ID_5332259176956426082" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy55QYISmn6APqoIuhZGGnuFWqWkgX-OtDIlUl6sjXxlPJrDAupIw-abScwdmQLApqjTodFrMku2g4weJWN9gLo6FZz1R_uI8TtJgwrxpk692DjVvY5ABu6mWs0iV6IIoOzZJyZMf7uxH9/s1600-h/6.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 216px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy55QYISmn6APqoIuhZGGnuFWqWkgX-OtDIlUl6sjXxlPJrDAupIw-abScwdmQLApqjTodFrMku2g4weJWN9gLo6FZz1R_uI8TtJgwrxpk692DjVvY5ABu6mWs0iV6IIoOzZJyZMf7uxH9/s400/6.jpg" alt="" id="BLOGGER_PHOTO_ID_5332259179696560930" border="0" /></a><br /></span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-1809223886007462712009-04-28T21:39:00.000-07:002009-04-28T21:51:07.802-07:00High Gain AmplifierThe amp is based on the High Gain PCB, so uses a pair of LM3876 (or LM3886) power opamps, run from a ±35V supply. I used a cut-down P88 preamp PCB because I only wanted one preamplifier stage, but the entire board can also be used. Alternatively, the P19 amp can be run at higher gain than normal, alleviating the need for a preamp at all. The down side of this is that the noise level will be higher, and background noise may be audible with efficient speakers and/ or very quiet surroundings.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6pJ12n3R5Y1vZTYbBWRNilq8N3ZV1P7eIe2RGYaWY8b-VV7RDmdP8GqjzF1oJ6Hai6dIqIhnbgb2PJpchu9CfBJgitF9k05PrskT8e9exgzxE6-YYe72Hfp7sV1R2soePyKFmXKIuRAkN/s1600-h/1.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 263px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6pJ12n3R5Y1vZTYbBWRNilq8N3ZV1P7eIe2RGYaWY8b-VV7RDmdP8GqjzF1oJ6Hai6dIqIhnbgb2PJpchu9CfBJgitF9k05PrskT8e9exgzxE6-YYe72Hfp7sV1R2soePyKFmXKIuRAkN/s400/1.jpg" alt="" id="BLOGGER_PHOTO_ID_5329969509250001634" border="0" /></a><br />The internal layout can be seen best in Figures 2 and 3. The main heatsink runs down the middle of the amp, and it separates the input and output stages. The material is 10mm thick aluminium, 45mm high and 180mm long. Because this is a prototype of the chassis assembly, there are several things that I would do differently if I build another. The chassis is more complex than it should be, and there are several opportunities for simplification. These became obvious after the basic chassis was well underway (naturally), and there were holes that I couldn't 'undrill' to simplify construction. Such is life.<span class="fullpost"><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMDp8DFYdX1fQ1GcslF3Jj90jgMTjGq4ncsvTtePeovFSWnK77CKeNjyGPOQuEqMc8RVkszCFe3oNic3sayRqfY0Vn-7cC1B0avq-t_ctuRyAd0LVdvosBRXU6_M1Hd0v3pdIDput9xZuC/s1600-h/2.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 333px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMDp8DFYdX1fQ1GcslF3Jj90jgMTjGq4ncsvTtePeovFSWnK77CKeNjyGPOQuEqMc8RVkszCFe3oNic3sayRqfY0Vn-7cC1B0avq-t_ctuRyAd0LVdvosBRXU6_M1Hd0v3pdIDput9xZuC/s400/2.jpg" alt="" id="BLOGGER_PHOTO_ID_5329969508872827394" border="0" /></a><br />The front top view shows the general layout of the amp's internals. On the left is the sheet aluminium clamp that holds the capacitors in place, and against the central heatsink section is the P19 amp board. On the other side of the heatsink is the input selector switch and then the ½ P88 board.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBDlJgvx3vfrHMNLKtf8ufIziugTO8nhkg4CnCCgJeylKuvkcxx3vFeceJDsRpeXlIIsdl9qkETnfuig7vn9aQsIyGFSGkLp9iIZxCFeixqOML8aiTqYNuizZ1gLOWU8fsRTRNSSkNg10i/s1600-h/3.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 204px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBDlJgvx3vfrHMNLKtf8ufIziugTO8nhkg4CnCCgJeylKuvkcxx3vFeceJDsRpeXlIIsdl9qkETnfuig7vn9aQsIyGFSGkLp9iIZxCFeixqOML8aiTqYNuizZ1gLOWU8fsRTRNSSkNg10i/s400/3.jpg" alt="" id="BLOGGER_PHOTO_ID_5329969515591965138" border="0" /></a><br />Along the rear (from left to right) is the DC connector, speaker outputs and inputs. As it turns out, 4 inputs is enough for my application, and had I restricted it to that the shield between the last set of inputs and the speaker connectors would not have been needed.<br /><br />The DC connector, speaker connectors and input RCA sockets are all mounted on blank fibreglass PCB material to insulate them from the chassis. Where needed, the copper was removed to create a rudimentary PCB pattern - this is evident on the DC and speaker panels. The boards were 'etched' using a rotary tool (Dremmel or similar). Although the resolution and accuracy are not good enough for an amplifier, this method works very well for such applications.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZiIysPUlITfq_keebJCRVK8J3qj1g5LbZbyfGx7jaEIqjsTaucF-MhES_vqZIDzyX28qDcdx6Y8FBBma9M-CiXVi_wYWDcz8Yn2Jb3R5krpGq67NxdGr3wBzsVvyu54lsbh8L4KmnYzs9/s1600-h/4.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 213px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZiIysPUlITfq_keebJCRVK8J3qj1g5LbZbyfGx7jaEIqjsTaucF-MhES_vqZIDzyX28qDcdx6Y8FBBma9M-CiXVi_wYWDcz8Yn2Jb3R5krpGq67NxdGr3wBzsVvyu54lsbh8L4KmnYzs9/s400/4.jpg" alt="" id="BLOGGER_PHOTO_ID_5329969512004132946" border="0" /></a><br />The back view shows the vent slots along the top, and you can see that the RCA connectors do not contact the chassis. Naturally, the speaker terminals are insulated. The DC connector is clearly visible on the right. It is a lot easier to simply make the back panel a little shorter than the other panels than it is to cut slots as shown. Even with a milling machine, these are somewhat tedious to do, and it is difficult to get perfect alignment without proper jigs. The hole for the DC plug and socket is relatively easily made using a drill and square file. The switch hole will require some fairly tedious filing if you use a rectangular switch as shown, however you can use any switch at all, because it only has to switch 9V AC.<br /><br />Again, the slots look cool, but a series of holes will work just as well. There are a number of other refinements as well, and these are listed in the construction section below.<br /><br /><span style="font-weight: bold;">The Electronics</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8fEF3VDLctJIf5lvc2x4zUJjagQcH-sx1teIs44ihsgQOkUFJogp-3cXLkPggno0ftlg6feCLteU_rqUtqYU8CHQ7St6dS5JcYz4MNaCxmGJZb0ONRQw7FXvFUs2QMZm2XFGU4qDpFtHP/s1600-h/7.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 160px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8fEF3VDLctJIf5lvc2x4zUJjagQcH-sx1teIs44ihsgQOkUFJogp-3cXLkPggno0ftlg6feCLteU_rqUtqYU8CHQ7St6dS5JcYz4MNaCxmGJZb0ONRQw7FXvFUs2QMZm2XFGU4qDpFtHP/s400/7.gif" alt="" id="BLOGGER_PHOTO_ID_5329970690791780978" border="0" /></a>As noted above, the electronics are based on two existing projects - P19 stereo 50W amplifier, and P88 high quality preamp. The schematic is shown below (one channel only), and the P88 only uses the second half of the PCB. The P19 power amp is constructed normally, and there are no changes from the published project.<br /><br />The inputs can be designated with whatever you want, and you can add more if desired (within the limits of the rear panel real estate). It is important that the gain of the preamp section is kept low enough to ensure that none of your inputs will clip the opamp. Assuming that CD/ DVD players are capable of about 2V, this means that the gain must be kept below 6.5 (16dB). This is not a problem unless you change the values of R7A, B and C, since the maximum gain is limited to about 9.5dB with the values shown.<br /><br />The caps before and after the volume control can be bypassed completely (using wire links), but I do not recommend that you do so. If there is DC across the pot,it will become noisy and scratchy after a while. Even small amounts of DC can cause problems.<br /><br /><span style="font-weight: bold;">Power Supply Module</span><br /><br />The power supply I used is probably overkill, but I simply used parts I had on hand. The schematic is shown below. Although I used zeners for the opamp supply as shown, some constructors are bound to be uncomfortable with such a simple arrangement. The P05 board can be used to provide full regulation, but with only one dual opamp, I'm not sure it is warranted.<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkJPyhmFVNZqWGq0_JTTVQ1-uERBJPiQk8ikkCDKoujXaxRaAYW2Dx4YtrmpidI8rFNL0zbAFl1Ov80nOidtSP-EdzvFctxIL_L-x6JgFnE7-UNKDeD_kUdy9DM6z0HXGcVCnNUi9u6PrN/s1600-h/6.gif"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 160px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkJPyhmFVNZqWGq0_JTTVQ1-uERBJPiQk8ikkCDKoujXaxRaAYW2Dx4YtrmpidI8rFNL0zbAFl1Ov80nOidtSP-EdzvFctxIL_L-x6JgFnE7-UNKDeD_kUdy9DM6z0HXGcVCnNUi9u6PrN/s400/6.gif" alt="" id="BLOGGER_PHOTO_ID_5329969513809577154" border="0" /></a>A photo of the cpmplete module is shown below. The soft start isn't really needed with a 160VA transformer, but it does no harm, and allows remote low voltage switching. Since this was a requirement (the connectors are illegal for use with hazardous voltages), it was a small price to pay. Although the transformer is happy without the soft start, there is a total of 20,000uF on each supply rail, and this would place great stress on the bridge rectifier.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbbvOwWXcVQTfzu0GRw2-fN03Yu5Mu-KdQfr6PA355K5T_fVGx7BBPXyygTtzRDklR9s_viiDCZE4_3NXPMrCMij0k3Bg9Zxf92ue8OT5XqrRSvqWMOWTBzXd2G6LM-m3G8_q8vEo3cjaf/s1600-h/8.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 204px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbbvOwWXcVQTfzu0GRw2-fN03Yu5Mu-KdQfr6PA355K5T_fVGx7BBPXyygTtzRDklR9s_viiDCZE4_3NXPMrCMij0k3Bg9Zxf92ue8OT5XqrRSvqWMOWTBzXd2G6LM-m3G8_q8vEo3cjaf/s400/8.jpg" alt="" id="BLOGGER_PHOTO_ID_5329970298930596322" border="0" /></a><br />The two 2.2k 1W resistors across the filter caps in the supply box ensure that the caps will discharge even if the amplifier is not connected. They are not strictly needed, but are recommended to prevent nasty sparks is the amp is connected while the caps are still charged. Large electros can easily maintain a respectable charge for many hours.<br /><br />The power supply is conventional in almost all respects. I used a 160VA transformer, a 400V 35A bridge rectifier, and a total of 20,000uF per supply rail - 4 x 10,000uF caps in all. When the connecting cable resistance is added in, there is almost no ripple at all at the amplifier, even with both channels at full power. The cable resistance aids filtering, but at the expense of slightly reduced maximum continuous power. I obtained over 40W per channel with both channels driven into an 8 ohm load, and peak short term power is over 60W / channel.<br /><br />You can use less capacitance of course, but with some increase in ripple and (perhaps) noise. For an amp of this nature, I expect that few constructors will want to use less than about 4 x 4,700uFcaps. Additional capacitance can also be used in parallel with the zener diodes, but 100uF 16V caps fit the P88 board easiliy. There is nothing to suggest that more capacitance will serve any purpose.<br /><br />Since the amplifier is absolutely dead quiet even at full volume with unterminated inputs, there is nothing one can do to make it any better. Placing one's ear right next to the speaker (one of average sensitivity), circuit noise is just audible. There is no hum at all.</span>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-4802127755044368320.post-79791731326676629872009-04-26T18:42:00.000-07:002009-04-26T18:53:57.524-07:00Super Amplifiers 300W Output PowerThe circuit described on this page is a modification of the original Double Barreled Amplifier. The circuit has been simplified somewhat. The circuit board layout is smaller and much more compact. The driver transistors now mount on the circuit board instead of on external heat sinks. And the circuit has the feedforward compensation that I describe for the Low TIM Amplifier.<br /><br />The original circuit board for one channel had eight 5-watt resistors on it, one in series with the emitter of each output transistor. On the new layout, four of these have been moved to the heat sink channel where they solder between pins of the transistor sockets. This change not only helps make the circuit board smaller, but it eliminates eight wires between the heat sink and the circuit board. One of the figures below illustrates how these resistors are installed in the heat sink channel.<br /><div style="text-align: center;"><br /><object width="525" height="444"><param name="movie" value="http://www.youtube.com/v/9c2Sj-sqWk4&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1"><param name="allowFullScreen" value="true"><embed src="http://www.youtube.com/v/9c2Sj-sqWk4&color1=0xb1b1b1&color2=0xcfcfcf&hl=en&feature=player_embedded&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="525" height="444"></embed></object></div><br /><br />If you build this amplifier, you must keep the wiring between the heat sinks and the circuit boards as short as possible if you don't want oscillation problems.<br /><br />When you test the circuit boards before connecting the power transistors, temporarily connect a 10 ohm resistor in series with a 0.1 ufd capacitor from the loudspeaker output to the power supply ground.<span class="fullpost"><br /><br /><span style="font-weight: bold;">The Circuit Boards</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5zoozV-EeV_4uGbJzyioyodwODfkf2iwEC8IZoxcPBdetr0vhqVoj-oQhDatuz9LTOc5aOfEtJewNSxfQd2tfYyoCxOQc_YgMBkSQk1r8ciNdCU8h2EAo9Mehq9-zltO4dIOj1p_7ZOqd/s1600-h/8.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 203px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5zoozV-EeV_4uGbJzyioyodwODfkf2iwEC8IZoxcPBdetr0vhqVoj-oQhDatuz9LTOc5aOfEtJewNSxfQd2tfYyoCxOQc_YgMBkSQk1r8ciNdCU8h2EAo9Mehq9-zltO4dIOj1p_7ZOqd/s400/8.jpg" alt="" id="BLOGGER_PHOTO_ID_5329181641037284770" border="0" /></a><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1_5cywyZihsfsTRcvY9uF8CNUaERVGYESi5PnwRDmZrD58iJXudQi9Ztnz3YJsOxUkkJ8WXoUKU7i0Mp0ElZ02lXAIXnV6XgxMpq6g0uelJVLbcsj6d1KUx5J063Aobm5wo9pwMkSHDu7/s1600-h/4.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 244px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1_5cywyZihsfsTRcvY9uF8CNUaERVGYESi5PnwRDmZrD58iJXudQi9Ztnz3YJsOxUkkJ8WXoUKU7i0Mp0ElZ02lXAIXnV6XgxMpq6g0uelJVLbcsj6d1KUx5J063Aobm5wo9pwMkSHDu7/s400/4.JPG" alt="" id="BLOGGER_PHOTO_ID_5329181637267873378" border="0" /></a><br /><br />We do not have circuit boards for the Double Barrelled Amplifier. If you wish to build it, you must make your own. Two drawings show the parts layout on the board, one with circuit traces and one without. These are scaled by a factor of 1.5. The other shows the circuit traces only. All layout views are from the component side of the board. You must flip the layout for the foil traces over to obtain the solder side view. The circuit board measures 4 inches by 6 inches. To my knowledge, there are no errors in the layout. If you decide to use it, you should carefully check it for errors because I could have easily made a mistake.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEYojZ5Ap5EIe8PevELe6ZoSajUPUrRuBnyDcKppi2Z1oPsFw9sR_Qa56iqGJGfnKymmP4Md1tYDVAAviKgbs3TvIKkPNphVL0NpM2LJq7Vc1WOEk9bomh6BywwKf7Nc3bhLRvNnZAwyaq/s1600-h/5.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 270px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEYojZ5Ap5EIe8PevELe6ZoSajUPUrRuBnyDcKppi2Z1oPsFw9sR_Qa56iqGJGfnKymmP4Md1tYDVAAviKgbs3TvIKkPNphVL0NpM2LJq7Vc1WOEk9bomh6BywwKf7Nc3bhLRvNnZAwyaq/s400/5.JPG" alt="" id="BLOGGER_PHOTO_ID_5329181634865189106" border="0" /></a><br />We do not recommend that you make the circuit boards unless you have experience in doing it. A source of materials for making your own printed circuits can be found here. I have been told that their "Press and Peel Blue" product (not the wet stuff they sell) can be used to successfully make boards with traces as narrow as 0.01 inch. The smallest traces on the amplifier layout are 0.03 inch wide. The PnP Blue product is basically a transfer medium that allows you to transfer the toner image from a laser printer directly onto bare copper clad board and then etch it in FeCl3 (ferric chloride).<br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUGTuaxBIa307SMaMULj_C0prTki4gIyvAWGnuV61NQ8jUNRqBoIMe-SsomOJQ_qgpoqjHXrr9nsWw1oOHSf-T25JkVgfLP3TDhM-HDqRoQ7Xw4hs0w6jz0e7wqjBY9Rx9VL0XeBFLEhHc/s1600-h/6.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 274px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUGTuaxBIa307SMaMULj_C0prTki4gIyvAWGnuV61NQ8jUNRqBoIMe-SsomOJQ_qgpoqjHXrr9nsWw1oOHSf-T25JkVgfLP3TDhM-HDqRoQ7Xw4hs0w6jz0e7wqjBY9Rx9VL0XeBFLEhHc/s400/6.JPG" alt="" id="BLOGGER_PHOTO_ID_5329181637558239154" border="0" /></a><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHYRcTSgJifrc7pAzV947x5txu5K8zcs9DgP_lmcRWDZKXtW1Lr-Be9VNn5osuWPgJUbVXOXSzqYBbVs2-dVX1LDfNPEa8j-_jUAo91wkOyGKBeeaz1zHSj1-eM6bkRFKWzlIDkeHPMqad/s1600-h/7.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 172px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHYRcTSgJifrc7pAzV947x5txu5K8zcs9DgP_lmcRWDZKXtW1Lr-Be9VNn5osuWPgJUbVXOXSzqYBbVs2-dVX1LDfNPEa8j-_jUAo91wkOyGKBeeaz1zHSj1-eM6bkRFKWzlIDkeHPMqad/s400/7.JPG" alt="" id="BLOGGER_PHOTO_ID_5329181638685056578" border="0" /></a><br /><br />After you etch the board, the copper should be cleaned with steel wool, lightly coated with solder flux, and then "tinned" with a soldering iron and rosin core solder. Do not use a commercial tinning solution that you dip the board into. It is almost impossible to solder a board that is tinned with one of these products because they corrode very quickly. When you drill the board, you should use the correct size drill bit for the pads. The hole diameters I recommend are: small pads - 0.032 inch, medium pads - 0.040 inch, large pads - 0.059 inch, mounting holes - 0.125 inch. If you do not use a sharp drill bit, you can pull the pads off the board when you drill it.<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuKwnY3qVKY1Jx2jpupqNVXZbCzyiOUjROwzFjwxjoLeojpN_p6kEALyxyCQjNk7eDhLmoLzMVFx5gxwHcelsqobztIBGUdEnpJ5UUhhr8MRECkPJnDckB64fu1yQ5Azd1DHlEpYeTQtyT/s1600-h/9.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 276px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuKwnY3qVKY1Jx2jpupqNVXZbCzyiOUjROwzFjwxjoLeojpN_p6kEALyxyCQjNk7eDhLmoLzMVFx5gxwHcelsqobztIBGUdEnpJ5UUhhr8MRECkPJnDckB64fu1yQ5Azd1DHlEpYeTQtyT/s400/9.jpg" alt="" id="BLOGGER_PHOTO_ID_5329182379305621714" border="0" /></a><br /><span style="font-weight: bold;">Circuit Description</span><br /><br />If you compare the Double Barreled circuit to the Low TIM circuit, you will see a lot of similarity between the two. Indeed, there is a Low TIM Amplifier embedded in the Double Barreled Amplifier. The major difference between the two is that transistors are added in series with those in the Low TIM circuit to form the Double Barreled circuit. By doing this, the voltage across the transistors is decreased so that the power supply voltage can be increased for higher output power.<br /><br />Basically, the circuit description for the Low TIM Amplifier also applies to the Double Barreled Amplifier. The major difference between the two is the addition of transistors Q22 through Q31. Q22 is connected as a common base stage at the output of Q12. The two transistors form a cascode stage. The base of Q22 connects to the junction of R52 and R54. These two resistors are equal and are connected as a voltage divider between the loudspeaker output and the positive rail. This forces the base voltage of Q22 to float half way between the loudspeaker output voltage and the positive power supply rail. Similarly, Q13 and Q23 form a cascode stage. R53 and R55 force the base of Q23 to float half way between the loudspeaker output voltage and the negative power supply rail. The addition of Q22 and Q23 cause the collector to emitter voltages of Q12 and Q13 to be approximately one-half of what the voltages would be without Q22 and Q23.<br /><br />Transistors Q24 and Q25 connect in series with the pre-driver transistors Q14 and Q15. The base of Q24 floats half way between the output voltage and the positive rail. The base of Q25 floats half way between the output voltage and the negative rail. The addition of Q24 and Q25 cause the voltages across Q14 and Q15 to be approximately one-half of what they would be without Q24 and Q25. Similarly, transistors Q26 through Q31 cause the voltages across Q16 through Q21 to be approximately one-half of what they would be without Q26 through Q31. By connecting the transistors in series in this way, the rail voltages can be increased for higher output power.<br /><br />The basic construction details of the Low TIM Amplifier also apply to the Double Barreled Amplifier. There are two short circuit jumper wires that must be soldered on the circuit board. These are marked with a J on the layout. In addition, you must solder a short circuit jumper in place of C6B if you use a non-polar capacitor for C6A. This is explained in the parts list for the Low TIM Amplifier. Because there are eight output transistors, two main heat sinks per channel are required. Q18, Q20, Q28, and Q30 should be mounted on one and Q19, Q21, Q29, and Q31 on the other. Resistors R61 through R64 and wires connecting the collectors of Q18 and Q20 and the collectors of Q19 and Q21 mount on the heat sinks. These connect between lugs on the transistor sockets. The four bias diodes D1 through D4 can be mounted on either heat sink. It is not necessary to divide the diodes between the two heat sinks because both heat sinks will operate at the same temperature. I recommend setting the voltage across Q7, i.e. the voltage between the collectors of Q22 and Q23, so that that amplifier is biased at 120 mA. This will give the same quiescent power dissipation per heat sink as in the Low TIM Amplifier.<br /><br /><span style="font-weight: bold;">Testing the Circuit Boards</span><br /><br />After you solder the parts to the circuit board, it is tested using the same procedure specified for the Low TIM circuit board. First, you must solder the short circuit jumper across Q7 and you must solder the 100 ohm 1/4 W resistors from the loudspeaker output to the emitters of Q16 and Q17. If you don't have a bench power supply that puts out plus and minus 85 to 93 V dc, you can test the circuit board at a lower voltage. I would prefer test voltages of at least plus and minus 50 V dc. An option is to connect bench power supplies in series to obtain the plus and minus 85 to 93 V dc. I have routinely connected two 40 V Hewlett Packard power supplies in series with the positive and negative outputs of a Hewlett Packard 50 V dual power supply, and I have never had any problems. To protect the circuit boards, you might want to put a 100 ohm 1/4 W resistor in series with the plus and minus power supply leads for the tests. The current drawn by the circuit should be low enough so that the voltage drop across these resistors is less than 1 V if nothing is wrong on the circuit board. There are 2 ground wires from the circuit board. Both must be connected when testing the boards.<br /><br />I can't stress how important it is to be careful in testing a circuit board. Even simple errors can cause the loss of many expensive transistors. I always use current limited bench power supplies to test a circuit board before and after connecting the power transistors. I also bias an amplifier using current limited power supplies in place of the amplifier power supply. When I initially power up an amplifier with its own power supply, I always use a Variac variable transformer to slowly increase the ac input voltage from 0 to 120 V rms while observing the amplifier output on an oscilloscope with a sine wave input signal. If I see anything wrong on the oscilloscope, I turn the Variac to zero and try to diagnose the problem using the bench power supply. I never use a load on the amplifier for these tests.<br /><br /><span style="font-weight: bold;">Parts List</span><br /><br />With the following exceptions, the parts for the Double Barreled Amplifier are the same as for the Low TIM Amplifier.<br /><br /><span style="font-weight: bold;">Capacitors</span><br /><br /><ul><li>C10, C11 - 15 pF mica</li><li>C13, C14 - 100 uFd 100 V radial electrolytic</li><li>C21, C22 - 47 uFd 100 V radial electrolytic</li><li>C26, C27 - 270 pF mica</li><li>C28 - 0.01 uFd 250 V film</li></ul><br /><span style="font-weight: bold;">Transistors</span><br /><br /><div style="text-align: left;"><ul><li>Q1, Q2, Q5, Q7, Q9, Q10 - MPS8099 or MPSA06</li><li>Q3, Q4, Q6, Q8, Q11 - MPS8599 or MPSA56</li><li>Q23, Q24 - 2N3439</li><li>Q22, Q25 - 2N5415</li><li>Q26 - MJE15030</li><li>Q27 - MJE15031</li><li>Q28, Q30 - MJ15003</li><li>Q29, Q31 - MJ15004</li></ul></div><br /><span style="font-weight: bold;">Diodes</span><br /><br /><ul><li>D5, D6 - 1N4934 fast recovery rectifier</li><li>D13 through D16 - 1N5250B 20 volt zener diode</li></ul><br /><span style="font-weight: bold;">Resistors</span><br /><br /><ul><li>R13, R14 - 5.6 kohm 1 watt (This value is for 85 V power supplies. For other power supply voltages, the formula is on the Parts List page for the Leach Amp.)</li><li>R28, R29 - 200 ohm 1/4 watt</li><li>R30, R31 - 3.9 kohm 1 watt</li><li>R37 through R40 - 470 ohm 1/4 watt</li><li>R41 through R44 - 10 ohm 1/2 watt (changed 6/27/00)</li><li>R52 through R55 - 6.2 kohm 1 watt</li><li>R56 through R59 - 10 ohm 1/2 watt (changed 6/27/00)</li><li>R60 - 39 ohm 1/4 watt</li><li>R61 through R64 - 0.33 ohm 5 watt. These 4 resistors are mounted on the heat sinks between solder lugs on the power transistor sockets. The wires that connect the collectors of Q18 and Q20 and the collectors of Q19 and Q21 are also soldered between the lugs on the sockets. Keep all leads as short as possible and use insulation stripped from hookup wire around the bare leads of the resistors.</li><li>R65, R66 - 300 ohm 1/4 watt</li></ul><br /><span style="font-weight: bold;">Heat Sinks</span><br /><br /><ul><li>Double the number of heat sinks required for the Low TIM Amplifier.</li></ul><br /><span style="font-weight: bold;">Power Supply Components</span><br /><br />The power supply circuit diagram is the same as for the Low TIM Amplifier. The parts are the same with the following exceptions.<br /><br /><ul><li>T1 - The transformer should have either a center tapped secondary or two separate secondary windings which can be wired in series. With 120 V ac rms applied to the primary, the no load secondary voltage should be 120 to 130 V ac rms for a center tapped secondary or 60+60 (60x2) to 65+65 (65x2) V ac rms for two secondary windings. This should give a no load amplifier power supply voltage of plus and minus 85 to 93 V dc. Some transformers are rated at 115 V ac rms on the primary. With 120 V ac rms applied, the secondary voltage will be greater by a factor 120/115. If the transformer is rated at full load, its no load voltage will be 15% to 20% higher. I would recommend a transformer current rating of at least 6 A. The transformer I used in each of my two original Double Barreled Amplifiers was the Signal 230-6. It had two center tapped 115 V 6 A secondaries which I wired in parallel to obtain a secondary rating of 115 V at 12 A. The primary had three voltage taps: 105 V, 115 V, and 125 V. I wired the AC line input to the 115 V tap. With 120 V AC applied to the 115 V tap, I got plus and minus 85 V DC on the power supplies and 270 W into an 8 ohm load. If I had used the 105 V primary taps, the power supply voltage would have increased to about 93 V and the amplifiers would have put out over 300 W. The Signal transformer was definately an overkill. It weighed 38 pounds. But it would really kick you know what. To my knowledge, this transformer now is available only by special order.</li><li>C1P, C2P - I used two Mallory CG832U100G1 8,600 uFd 100 V capacitors in parallel for each of these so that I had 34,400 uFd total in each of my two amplifiers. This was probably an overkill. The energy stored in the eight apacitors was about 250 joules. This is enough energy to lift a 25 pound dog over 7 feet off the floor. For C1P and C2P, I would recommend at least 10,000 uFd total for each. The voltage rating should be 100 V or greater.</li></ul></span>Unknownnoreply@blogger.com0