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  1. audioguru2

    Differential amp vs op-amp

    A single opamp used as a differential amp isn't useable because negative feedback to its inverting input causes that input to be a low impedance much less than its non-inverting input. Therefore 3 opamps are used, with 2 opamps at the inputs of the differential amp. Then the circuit has a high...
  2. audioguru2

    Car Amp!!!

    That is a nice amp for a good price. Its logo "Dual" is the German company that made my old turntable for vinyl records.
  3. audioguru2

    0-30 Vdc Stabilized Power Supply

    Good and you are welcome. It would be a nuisance to switch it. Just leave it on 199.9V and its reading will be within 0.1V.
  4. audioguru2

    temperature sensor with digital output

    It needs an amplifier to boost its output of only 10mV/degree C. Program the microcontroller for it. The circuit's current is very low. Calculate or measure it. The LM317 regulator is missing a resistor, therefore its output voltage is only 1.25V. The circuit's current is very low. Calculate or...
  5. audioguru2

    audio amplifier for my car speakers

    Hi Jc, Welcome to our forum. ;D It is easy to build a 14 Watts per channel stereo amp for a car, like our "22 Whats" amp project that uses a single IC. http://www.electronics-lab.com/projects/audio/006/index.html It is very complicated to build a high power amp because it needs a high power...
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

    How much voltage is across a short? 1uV? 10uV?
  7. audioguru2

    about mixer

    The mixer connects to a power amplifier that you have attached in this thread. You can measure the level of the amplified mic at the output of the preamp and at the output of the mixer. The mic is a low-level signal input. "Level input" doesn't make sense and is not used. Correct. Your circuit...
  8. audioguru2

    74LS193 and CD74HCT193E

    The 74LS uses bipolar transistors. The 74HCT uses Mosfet transistors. Their families are completely different. You could look over their datasheets, or just try using the wrong IC. You can't get the transmitter's ICs, you can't get its zener diodes. Therefore I suggest buying the kit if it is...
  9. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Ron, I changed the parts so that the project will be able to have an output of 30V at 3A with good regulation. It will also be able to have an output of 0V at 3A (shorted output or a very low output voltage at full current) without anything getting too hot and failing. The opamps were...
  10. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Ron, I recommend this parts list for the project to work well and be reliable. A few months ago someone recommended adding trimpots in series with the controls for calibration.
  11. audioguru2

    detailed theory about fm transmitter

    A link to a review of the Veronca transmitter kit in Google doesn't work anymore, but I found it in Google's cache: "Circuit Description The transmitter is based on a novel double-ended free-running voltage controlled oscillator (VCO) operating at half the output frequency. Note stations based...
  12. audioguru2

    Bootstrap Circuit

    This link shows how bootstrapping reduces distortion by 10 times: http://www.dself.dsl.pipex.com/ampins/discrete/twoq.htm The capacitor causes a constant current to flow during signal changes in the transistor's collector resistance. Constant current means the resistor has a higher impedance...
  13. audioguru2

    veronica fm transmitter

    Hi Tinu, Reliability? So it lasts without failing? Who knows? The kit is fairly old so I don't think all its parts are still available. It RF transistors and varactor diodes must be very hard to find. I don't think its performance would be good: 1) It is mono FM, not stereo like modern...
  14. audioguru2

    Long-life circuit for LEDs and a clock

    Hi DaButtery, Welcome to our forum. ;D 1) You don't need 6 battery cells. Two 3.4V LEDs in series need a 6.8V supply, but the current limiting parts need more. 6 battery cells in series make 9V when new but drop to 6V during their life but then the LEDs would not be lighted. Use 4 battery cells...
  15. audioguru2

    Bootstrap Circuit

    Hi Alex, Welcome to our forum. ;D Are you talking about bootstrapping the collector load of a transistor so it is more linear, has more gain and has a wider voltage swing?
  16. audioguru2

    Help On Another Transistor Question

    1) R1 and R2 make a voltage divider. You don't need the formula to determine their divided vol tage, just use Ohm's Law. 2) Subtract the Vbe voltage to determine the emitter voltage and its current. 3) Use Ohm's Law to determine the collector voltage from the emitter current. 4) If you want to...
  17. audioguru2

    Op amps boosting Ultra sonic signals?

    Hi Laz, Welcome to our forum. ;D The old LM358 opamp has poor high frequency response. It can't reach max output above only 5kHz and its max gain at 40kHz is only about 10. There are many newer opamps with a much wider bandwidth but my favourite is the TL071 single, TL072 dual and TL074 quad...
  18. audioguru2

    i need help extending the keys finder project. can someone help me out????

    Of course the LED won't work if its battery has the wrong polarity. If you replaced the tiny LR41 button cells battery with your power supply then the LED might be burnt out because it doesn't have a resistor to limit its current.
  19. audioguru2

    Nec D560

    NEC's 2SD560 info is available at www.datasheetarchive.com .
  20. audioguru2

    Low-pass Filter?

    Hi Raymond, An inverter with a pure sinewave output would be expensive and complicated. It would operate with PWM like a class-D audio amp. I don't need an inverter with reliable nuke generating stations all around me and Niagara Falls nearby.
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