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  1. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Emiliano, Where do you have 70VAC? The 7107 voltmeter needs its own power supply that is separate from what it is measuring. See its own thread. If you made 2 power supplies so that they can be in series for up to 60V, or so the output is positive and negative 30V, then each power supply...
  2. audioguru2

    Another INVERTER we can talk about..

    Hi Sasi, On your latest circuit, pin 7 of the 324 appears to always be high, and therefore doesn't do anything, just like in the original circuit. I think that pin 6 is missing a voltage reference which would allow pin 7 to go high only when the voltage on pin 5 is higher than the reference...
  3. audioguru2

    Generators

    Hi Steven, I'm sorry that you blew-up all those nice big greencaps. I think that your voltage-multiplier fed them too much voltage. If turning the motor produces AC, then its output needs a rectifier to charge those capacitors. But keep the voltage within their rating.
  4. audioguru2

    Another 4watt Transmitter Question

    Hi Marv, Perfect, it works well now. See, don't give-up, we are glad to help. Did you use a clip-on heatsink and thermal grease for T2 as in the picture? That Field Strength Meter will be good for tuning but it is designed for 90MHz and may need changes to its tuning parts. You will also need a...
  5. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Moh, Welcome to our forum. The absolute maximum supply voltage for a TL081 and most other opamps is +, - 18V which totals 36V. If you use a 24VAC (which is too low) transformer in this project, then it will produce about 27VAC or more when lightly loaded. Therefore the positive rectified and...
  6. audioguru2

    Audio amplifier

    Hi Mukhalled, The TDA1560 and TDA1562 ICs are the first "Class-H" circuits that I have ever seen! I wonder if you can hear them switch between Class-AB and Class-H, since they double the supply voltage during Class-H operation. The TDA1560 has a guaranteed minimum output of only 27W with a...
  7. audioguru2

    Another 4watt Transmitter Question

    Hi Marv, That's great that you got it working. Yeah, broken capacitors don't work very well. It will transmit much further if you use about 15 turns or more for L2. Use a 1M resistor that is big enough for that amount of your 0.2mm wire. With your 12V battery it won't have 4W of output, probably...
  8. audioguru2

    12v lamp Dimmer lamp ideas?

    Hi Kevin, How will you syncronize your variable-pulse-width 555 circuit to the mains frequency? The posted LSI IC does it with a built-in phase-locked-loop.
  9. audioguru2

    Another 4watt Transmitter Question

    Hi Marv, Your Walkman is OK and so is the wire for your coils, but L2 should be many turns of fine enamelled wire. Instead, wrap your 0.7mm wire around a 1M, 2W resistor, tightly and one end to the other. How many volts is your regulated (stabilized) power supply for this project? Can it supply...
  10. audioguru2

    Another INVERTER we can talk about..

    Hi MP, Math? But I can't find my old slide-rule! I'm glad that you agree that Sasi's relay turns-off his circuit, because my new-fangled calculator tells me that a 150A/hr car battery will power the maximum leakage current (25uA each at 55V) of the six MOSFETs for more than 116 years! Maybe...
  11. audioguru2

    Another 4watt Transmitter Question

    Hi Marv, I am sorry that it doesn't work for you. Please don't give-up so soon. We are finished joking about the project's translation and can help you more. High frequency RF circuits like this one, depend on many wiring tricks. The wiring between components must be very short (on a PCB, not on...
  12. audioguru2

    Another INVERTER we can talk about..

    Hi Ante, An inverter with 300W sine-wave output but without much heat? Sure, it's nearly the year 2005, isn't it? I'll look at using a class-D audio amp driver IC (but it will probably be surface-mount) and discrete MOSFETs. An output transformer will step-up the voltage and a low-power volume...
  13. audioguru2

    Another INVERTER we can talk about..

    MP, I'm sorry, the circuit is not truly isolated but instead simply reduces battery current drain. Sasi cleverly used a fairly fast-switching low current relay contact to accomplish this, instead of your recommended slow-switching high current relay. I thought that you were concerned that the...
  14. audioguru2

    Another INVERTER we can talk about..

    MP, Sasi's backup system circuit has RLY Pole #1 to "isolate the battery drain when the mains are on".
  15. audioguru2

    Another 4watt Transmitter Question

    If Steven made this circuit, it would have a corona discharge coming out of its antenna. He is cool, too!
  16. audioguru2

    Another 4watt Transmitter Question

    Hi Ante, Maybe the translation was wrong, and it meant for you to wind the inductors on a 75W resistor. That would make a big inductor. Then maybe the circuit will give 75W output. Do catering companies serve cold transmitters?
  17. audioguru2

    Another 4watt Transmitter Question

    Hi Ante, The text of that project was corrected in Feb./04, so it should be OK now: The power output probably depends more on "the tendency of catering" than anything else. I think that means that it will do whatever it wants to do. The instructions say that the inductors must be made of "air"...
  18. audioguru2

    Another INVERTER we can talk about..

    Hi Ante, Sure, the SG3524 will do a pretty good job here, and in addition to providing an adjustable "dead time", it can provide output voltage regulation and current-limiting, too. But its age shows in its single-ended outputs, designed for driving bipolar transistors, not high-gate-capacitance...
  19. audioguru2

    Another INVERTER we can talk about..

    Ohhhhhh! I get it! Thanks. The relay is for the inverter to give automatic changeover so that it can be a backup AC power supply when the mains fails. Your gamble is that the inverter will be overloaded for a moment if the load is a straining motor or an appliance with a huge filter capacitor...
  20. audioguru2

    Another INVERTER we can talk about..

    Hi Sasi, Congratulations, that's a nice simple circuit and a good PCB layout. What is the relay for? It looks like a relaxation oscillator, where the gate drivers start running then quickly turn-off then start again, etc. What are the paralleled 0.01 ohm resistors for? How much current does the...
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