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  1. C

    Inject sound to a phone landline

    This is what you asked for: "I would like to inject sound to a phone landline." You can connect the circuit to other wires but you wont get the advantage of the amplifier circuit in the phone
  2. C

    Inject sound to a phone landline

    My circuit goes across the incoming phone line
  3. C

    More efficient LDR "dark" switch?

    Here is a suitable circuit:
  4. C

    Inject sound to a phone landline

    The top wire of my circuit goes to the top wire of your drawing and the bottom wire of my circuit goes to the bottom wire of your circuit that has the arrow in one direction and the arrow in the other direction.
  5. C

    Inject sound to a phone landline

    Here is the simplest arrangement:
  6. C

    Zener diode

    You don't have to worry about the.................. [mod edited]
  7. C

    Inject sound to a phone landline

    All you need is 2 x 100n caps and a few resistors. I have sold hundreds of these items.
  8. C

    More efficient LDR "dark" switch?

    The circuits above are very inefficient. How much current do you want to source? In general, a Darlington can be used and it will consume about 3-10uA.
  9. C

    Need some help about this edge meter

    To get 30v,add 3 x 68k in series. To get 15v add 68k and half a 68k resistor in series. All done without any mathematics.
  10. C

    Bike Horn

    There are no spikes passed to the transistor. Look at the circuit. The piezo needs about 80v.
  11. C

    Help making voltage boosting circuit

    How much current do you want and what regulation.
  12. C

    Need some help about this edge meter

    Now try 22k 33k and 47k and keep going until the pointer doesn't quite reach FULL SCALE DEFLECTION. And let us know
  13. C

    Need some help about this edge meter

    It is called a movement You don't know the sensitivity of the movement so add a 10k resistor in series with the coil and apply an accurate 10v to the combination. See how far the needle moves up-scale and let us know. It could go more than full scale or less than full scale depending on the...
  14. C

    led lamp assembly help

    There are 3 LEDs in series NOT 6.
  15. C

    Jacob's Ladder help

    "Are you saying that this will not work with this transformer? or that it just wont be the safest choice?" You will find 1kW at the arc will blow your project up.
  16. C

    Oscillator and transformer project

    Try a Xenon circuit from a disposable camera. I'm not sure about the waveform Or a $3.00 Electroluminescence driver. It works a 400Hz and is sinewave
  17. C

    Trouble with solder

    Scratch the surface, use a HOT iron and make sure the iron has a large mass so the casing will get hot too. It must get HOT HOT.
  18. C

    IGBT Half-bridge Module Help

    How do you expect to convert DC to AC with this black box ???
  19. C

    IGBT Half-bridge Module Help

    What's an inverter?
  20. C

    Electric Shock from 24 volts

    Do not touch any other electrical wires or you will instantly electrocuted. You are very susceptible to getting killed. Some people have high resistance skin and they don't feel the shock. Others die at the first touch. You have been warned.
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