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  1. audioguru2

    Crystal examiner

    Hi Walid, I have never investigated a crystal oscillator. Of course the frequency of your oscillator circuit depends on the crystal. Google has lots of articles about the capacitor values required.
  2. audioguru2

    noisy power supply line

    Hi Kevin, The cheap amplifier might be fixed by adding a filter capacitor that costs only 35 cents. Maybe it has a ground loop that picks up noise.
  3. audioguru2

    Project Motorola Hi-Fi Amplifier

  4. audioguru2

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

    Hi Mandavar, A properly designed and connected car amplifier does not reproduce alternator whine. Its high gain circuit should be supplied with a filtered DC supply voltage. The filter is a resistor in series then a capacitor to ground at the amplifier's high gain circuit. A capacitor has...
  5. audioguru2

    LM2917N F-V converter IC

    hi Salvatore, I thought the values of the resistor and capacitors of the IC will solve your problem. A monostable "pulse-stretcher" can be made from a 555 or a couple of Cmos inverters.
  6. audioguru2

    Project Motorola Hi-Fi Amplifier

    Hi Shahriar, The circuit is odd. It has nothing to control its current. Some opamps have an operating current much higher than others and this amplifier's output transistors amplify the variation. If the output transistors heat and draw more current then there is nothing to sense the excessive...
  7. audioguru2

    LM2917N F-V converter IC

    Hi Salvatore, The datasheet talks about selecting R1, C1 and C2 values for a required response time.
  8. audioguru2

    How to build a Hall Audio system!

    Hi Shahriar, The placement and quantity of speakers in a hall depends on the length, width and ceiling height. Arenas and discos use directional speakers aimed at their nearby area so that distant areas don't hear an echo from them. If the ceiling is high enough then many distributed speakers...
  9. audioguru2

    PROFILE PA2120

    Sorry again. I have never heard of Profile. There are hundreds of car sound system manufacturers in the USA. I hope you find somebody who can fix your amplifier.
  10. audioguru2

    Drawing power from a single live wire

    Your RC control switch will probably blow up if it is powered directly from the mains. It probably needs a low DC voltage. There isn't enough space inside a wall switch box for an AC to low voltage DC adapter.
  11. audioguru2

    Drawing power from a single live wire

    Live and neutral are two mains wires, not just one. If the small signal device operates from your 120VAC or 230VAC mains and you want it to be powered all the time then connect it to the live and neutral wires separate from the load. Then connect the load to its switch in series also to the live...
  12. audioguru2

    audio amplifier

    The 22W Audio Amplifier project can provide 6.5W to each of two 6 ohm speakers at the same time. But satellite speakers are small and might be damaged if 6.5W of bass gets to them since they are usually used for only midrange and high frequencies with a separate powerful subwoofer playing the...
  13. audioguru2

    audio amplifier

    Hi John, Our 10W Mini Amplifier http://www.electronics-lab.com/projects/audio/016/index.html provides 1.9W into a 6 ohm speaker at clipping with a 12V supply. It is a mono amplifier project. Our 22W Audio Amplifier http://www.electronics-lab.com/projects/audio/006/index.html provides 6.5W into...
  14. audioguru2

    PROFILE PA2120

    Sorry M-a-r-i-n, I have never heard of Profile and I have never been to your country.
  15. audioguru2

    Auto dimming problem

    What is the voltage regulator for? What voltage? What is the diode for? It is normally used to protect the regulator if it has a big output capacitor and the input is suddenly shorted. Then the big output capacitor discharges into the diode instead of into the regulator's output. The pot R3 is...
  16. audioguru2

    Auto dimmer

    A quick search in Google found many good "darkness activated relay" circuits like this one:
  17. audioguru2

    Opamp

    National Semi has a power opamp. It is rare and is expensive. Why not use a common and inexpensive audio power amplifier IC? Why not use an ordinary opamp that is driving a transistor?
  18. audioguru2

    fm transmitter scematic required

    This Micromitter project is excellent and is used to transmit from an MP3 player to a car radio. I have seen them in stores. It has an attenuator on its output so remove it and make a 100MHz power amplifier for it.
  19. audioguru2

    Auto dimming problem

    Hi and welcome. ;D You picked a project that I think has mistakes in it. Maybe this is the project you made that has the pots directly across the car battery so of course they smoke. The 2N3906 transistor will also smoke because it is missing a protection diode to arrest the high voltage spike...
  20. audioguru2

    lesr sade from iraq the inverter 500w

    Hi Lesr, It is good that you used efficient Mosfets instead of old transistors. Does the CD4047 directly drive the Mosfets or did you use the dual opamp in between? I just noticed that our "corrected" project uses two quad opamps instead of a single dual opamp.
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