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  1. audioguru2

    LED power

    LEDs operate from current. If you connect an LED to a voltage supply then it will burn out because the current will be unlimited. The resistor in series with the LED or in series with a few LEDs in series limits the current according to Ohm's Law. Most ordinary small LEDs have a max allowed...
  2. audioguru2

    white led

    Bakelite Hylam Ltd. has made bakelite in India since 1947. Very old phones and tube radios were made of bakelite. Maybe now they make a newer plastic. I don't think you should have your 50 degrees C heatsink near it.
  3. audioguru2

    Gang specifications used in FM receiver.

    I don't think ganged tuning capacitors for making radios are sold anymore. If they were then their datasheet would say the pF of them. The nuts or small screws on a ganged tuning capacitor is to calibrate the frequency and to align their tracking.
  4. audioguru2

    AM reciever mixer

    Hi Walid, As the AM signal increases in amplitude then the oscillator signal's amplitude is also increased in the mixer. As the AM signal decreases in amplitude then the oscillator signal's amplitude is also decreased in the mixer. An AM signal has sum and difference sidebands. A mixer creates...
  5. audioguru2

    What Is This Chip

    In Google, I entered 74LS04 and 74LS86 and got links to their datasheets and descriptions of them.
  6. audioguru2

    precision rectifier

    Your have extremely low resistor values. Then the output impedance of your signal generator must also be extremely low. Your generator's output impedance might be 600 ohms so replace all the 330 ohm resistors with 10k.
  7. audioguru2

    Gang specifications used in FM receiver.

    Hi Shamim, Are you talking about a radio's ganged tuning capacitor? How many gangs depends on the quality of the radio. A good radio has an input tuned circuit, another tuned circuit following its RF amplifier and a 3rd tuned circuit for its RF oscillator. A cheap radio has only 1 or 2 tuned...
  8. audioguru2

    Electronic Eavesdropping Devices Detector

    Hi Eplanet, I think The Bug Detector With Beep is a radio transmitter that transmits Amplitude-Modulated beeps.
  9. audioguru2

    white led

    Hi Pier, If you used thermal grease between the LED and your little heatsink then it is fine. Without thermal grease then the LED is probably too hot inside. I don't know what is "hylem".
  10. audioguru2

    Electronic Eavesdropping Devices Detector

    Hi Ante, The Bug Finder circuit you posted is nearly identical to our Eaves Dropping Devices Detector project.
  11. audioguru2

    white led

    Hi Pier, Ordinary small LEDs have their brightness measured in candela or milli-candela units. Incandescent, fluorescent and very bright large LEDs have their brightness measured in lumens. One type of measurement takes into account the different sensitivity of our vision to different colors.
  12. audioguru2

    precision rectifier

    Then there are many ways to make a precision full-wave rectifier circuit.
  13. audioguru2

    precision rectifier

    Hi AN920, your circuit works because it is very different from the original circuit and is very similar to mine. I think it will measure like this:
  14. audioguru2

    Query about batteries

    Hi Sgt Siff, Welcome to our forum. ;D A 12V 100Ah battery is a pretty big car battery. 100A for 1 hour would probably cause its electolyte to boil then it would become dry. It can provide 100A or 200A for a few seconds to start a car's engine. It would provide 20A for 5 hours. An electric motor...
  15. audioguru2

    Problem in an H-Bridge

    A 10k resistor charges or discharges the 3nF capacitance of a Mosfet in about 30us. A Mosfet would be heating for that 30us. If your PWM frequency is 50kHz then each half-cycle is only 10us long so the Mosfets are never fully turned on and are not fully turned off. They are heating all the time...
  16. audioguru2

    precision rectifier

    A diode conducts in only one direction with a voltage drop of about 0.7V. You shouldn't do calculations with "ideal" diodes.
  17. audioguru2

    Electronic Eavesdropping Devices Detector

    Hi Eplanet, Your project looks very nice. Why are all the LEDs on? Is it picking up a very strong signal?
  18. audioguru2

    precision rectifier

    There is no need for resistors with such low values. Don't you think the humps on the original circuit will have different levels as I showed? I re-drew my circuit and used a dual-polarity supply. Its humps will be at equal levels up to a fairly high frequency.
  19. audioguru2

    precision rectifier

    The output minimum sink current of an LM324 is only 10mA which is only 6.6V across the 330 ohm feedback resistor. The simulator uses the typical current value of 20mA. With a very low input frequency that the old LM324 can handle and a very low source impedance, I think the output will not be...
  20. audioguru2

    Energy saving device - can they work?

    The ad says it reduces the power factor by the use of a "specially designed" capacitor. That is all. Maybe in China you pay more for electricity if the power factor is bad due to inductive loads.
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