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  1. audioguru2

    12v amplifier?

    Hi Chub, A single ordinary power amplifier IC like a TDA2003 has an output power of about 2W into an 8 ohm speaker at clipping with a 14V supply. Its power is 4.5W into 4 ohms, 6W into 3.2 ohms and 8W into 2 ohms. A power amplifier IC like the TDA2005 is bridged with two amplifiers and has an...
  2. audioguru2

    Help for Guitar Control

  3. audioguru2

    Help for Guitar Control

  4. audioguru2

    Flashing Heart Help!

    If I make a flashing heart, I would not throw away 10V and use it to heat 100 ohm resistors like in our project. I would not use an average tiny current of only 1.2mA in each LED. Instead I would connect five LEDs in series (for a 12V supply) and use a current-limiting resistor in series with...
  5. audioguru2

    Flashing Heart Help!

    Hi Mike, Welcome to our forum. ;D Our project has 142 LEDs. Did you use that many? The LEDs are directly in parallel which is not recommended because they might not all be exactly the same. The one with the lowest voltage will hog most of the current and burn out, then the next lowest voltage...
  6. audioguru2

    Reading a chip in situ

    There are many different kinds of ICs that have 8 pins. Most are opamps and dual opamps. The ICs don't "itentify" themselves so software can tell one from another. The clips are to allow you to connect a 'scope or a voltmeter to a working IC.
  7. audioguru2

    GSM signal sensor

    Hi Bassanova, We have a cell phone ringing detector circuit that maybe you can modify to do muting: http://www.electronics-lab.com/projects/misc/010/index.html
  8. audioguru2

    Help for Guitar Control

    Hi Splashsky, Welcome to our forum. ;D The TL062 dual opamp has FET inputs like the TL072 dual opamp. They cause an opamp to suddenly invert its output polarity when the input voltage exceeds the common-mode voltage rating which is low in this circuit using only 9V for its supply. The...
  9. audioguru2

    5 volt to 3.3 volt

    Indulis, I showed and explained why a low voltage zener diode makes a lousy regulator. IF the input voltage changes (but it doesn't here), and IF the load current changes (we didn't know that it doesn't here) then it is a lousy regulator when the temperature changes because its voltage changes...
  10. audioguru2

    Speed-limit Alert PLEASE HELP!!!!!!!!

    A Cmos inverter has a gain of about 30 with a 9V supply voltage. This circuit has 4 0f them cascaded so their total gain is about 810,000 so a tiny signal at the input causes the last few inverters to produce clean saturated square-waves. Here is a graph showing that the gain of a Cmos inverter...
  11. audioguru2

    inverter

    Hi Oranium, Welcome to our forum. ;D I think a 12V car battery and the alternator trying to charge it would explode if you attempt getting 200A continuously from it. For such a high amount of power, people use an engine-driven generator.
  12. audioguru2

    5 volt to 3.3 volt

    The 2nd reply was from Gazza who recommended a simple voltage divider. The next reply was from me adding an emitter-follower transistor to the voltage divider. Another reply from somebody recommended a lousy zener diode that is not needed and it was tested to perform wrong.
  13. audioguru2

    5 volt to 3.3 volt

  14. audioguru2

    IR Headphones

    With FM, The carrier frequency is changed by the modulation. You have a VCO that oscillates and drives the IR LED with 100kHz or another ultrasonic frequency from a VCO. Then the frequency of the VCO is changed by the audio modulation. Loud sounds in the modulation cause the carrier frequency to...
  15. audioguru2

    digital stetoscope 2!

    Hi Bynes, Please describe the sound. Is it distorted? Goes it have hiss? Does it have background sounds? Does the microphone or its cable make loud crackling noises when they are moved? Did you use the TL072 low noise opamp? Did you use new 9V alkaline batteries? Moderator, Please delete his...
  16. audioguru2

    Inductor in LC filter

    The 10kHz noise will drive you nuts. Use a carrier frequency above 20kHz so it won't be heard.
  17. audioguru2

    5 volt to 3.3 volt

    Arun's circuit gives the zener diode and transistor plenty of current so changes in load current don't cause changes in zener current. The input voltage is fixed so it doesn't change the zener current. So the zener should provide pretty good voltage regulation (as shown by Zeppelin) if its...
  18. audioguru2

    5 volt to 3.3 volt

  19. audioguru2

    electronic stesthoscope

    Did you make the Electronic Stethoscope-2 circuit? Please describe the sound. Is it distorted? Goes it have hiss? Does it have background sounds? Does the microphone or its cable make loud crackling noises when they are moved? Did you use the TL072 low noise opamp? Did you use new 9V alkaline...
  20. audioguru2

    0-30 Vdc Stabilized Power Supply

    Yes if you upgrade certain parts. A 28VAC transformer will be about 29VAC without a load. Its peak voltage is 41V and it will be rectified and smoothed into 39.6V. To have a 3A output then the transformer must be rated at 41V x 3A= 123VA which is 28VAC/4.4A. The opamps use the smoothed 39.6V...
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