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  1. audioguru2

    rf coil

    Hi Arsal, You got a pretty good grade. Nice going. ;D I was glad to help you.
  2. audioguru2

    FM Transmitter

    The transmitter and receiver both use the same ferrite rod loop antenna coil and tuning capacitor.
  3. audioguru2

    FM Transmitter

    The value of the E-Bay ferrite loop antenna coil isn't listed but it could be calculated since the value of its tuning capacitor is known and also the tuning frequency range. The 220uH coil has a low value so it needs a high value tuning capacitor to tune the AM tradio band.
  4. audioguru2

    FM Transmitter

    Crivoli, Don't you realise that the variable capacitor has to match the value of the ferrite loop coil antenna?
  5. audioguru2

    FM Transmitter

    The article for making the radio says to get a loopstick antenna and tuning capacitor from an old AM radio. The E-Bay loopstick antenna coil is fine. Also get the guy's tuning capacitor or the kit AM crystal radio that has both.
  6. audioguru2

    FM Transmitter

    AM radios don't have an external antenna. They use a ferrite rod which has the coil wound arround it. The transmitter might need a very long wire for an antenna for it to have any range.
  7. audioguru2

    FM Transmitter

    The projects don't say how much range they have. Make them and let us know.
  8. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Triple, I think your project works fine. The current regulator causes the voltage to be reduced until the set amount of current flows in the load. Try a 10 ohms load resistor: 1) 30V/10 ohms= 3.0A. 2) If you turn down the current setting then only 20V/10 ohms= 2.0A. 3) Turn it down more then...
  9. audioguru2

    Help with transformer

    Muhammad, With only half the transformer's voltage at its output, it will be severely overloaded if it is a powerful transformer! A cheap little transformer might have such poor internal regulation that its open-circuit output voltage drops to half with its rated load. But a half-decent...
  10. audioguru2

    TV tx

    I have an MC1374 in a TV convergence generator that I made about 30 years ago. Digikey is a huge electronics parts supplier and they don't list it, so it is probably not made anymore. The circuit you attached is not designed for your TV system.
  11. audioguru2

    TV tx

    Try searching on Google. This is on Google's 2nd link to an MC1374: http://www.epanorama.net/counter.php?url=http://www.spelektroniikka.fi/kuvat/mc1374.pdf
  12. audioguru2

    simple question about batt chargers

    I have never charged a lead-acid battery. My car does it without my attention.
  13. audioguru2

    FM Transmitter

    My son had a cheap radio controlled toy car. Its range was about 10 metres. Then I bought a good one for him with a range of about 100 metres. The radio systems for model airplanes have a range of about 1km. Look how far NASA can remotely control things!
  14. audioguru2

    FM Transmitter

    Make a simple FM transmitter and receive it on an FM radio.
  15. audioguru2

    FM Transmitter

    The toy car transmitter and receiver just makes the toy car go and stop. No sound. The walkie-talkie might work but there isn't any text. An expert might be able to make these circuits without a detailed parts list. The coils must be made exactly for their function. A pcb must be used with the...
  16. audioguru2

    Electronic Eavesdropping Devices Detector

    I don't know how sensitive is the Electronic Eavesdropping Detector. It might just pickup every radio and TV station, and taxi cab radio in town.
  17. audioguru2

    AUTO-MANUAL CLOCK GENERATOR

    Hi Sheldon, You have a nice circuit. ;D Shouldn't the transistor have a resistor between its base and emitter to quickly turn it off? About 22k would be fine.
  18. audioguru2

    FM Transmitter

    Did you want to transmit and receive a voice or music, or just an on and off command?
  19. audioguru2

    FM Transmitter

    That receiver IC hasn't been made for many years and isn't good. Some stores might have it or a newer one that also doesn't work well. Try one. It might be OK for your application.
  20. audioguru2

    FM Transmitter

    It is fairly easy to make a radio transmitter. It is difficult to make a radio because it has many more parts than a transmitter and some of the parts are available only in huge quantities.
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