Building an FM Transmitter

[James S]

[SmarterThanSam]

[Presto]

That makes no sense. If there's a voltage, you can power a circuit... You admit there's a voltage, but you say it can't power a circuit. That can't be. The speakers/headphones plugged into the audio jack complete the circuit.

Sure, the voltage of an audio signal is variable, but it's still voltage. What do you think powers speakers and headphones? "powers" being the keyword. That "power" is being sent through the headphone jack.

Why do you think every speaker requires two wires running to it? It's direct current passing through the wires, going in on one wire and coming back along the other, completing a... CIRCUIT.

We're not talking about "radio waves". We're talking about audio signals. Quite a difference there.

Thanks, and have a great day!

[Dan East]

My comment was in regards to powering an FM transmitter, which I should have made clearer. That would require a continuous flow of power. Of course you could hook up something like an LED (plus a proper resistor to match the impedance of typical headphones - probably 8 ohms), and watch it flicker.

Dan East

[James S]

But the voltage varies and completely dies (when there's no sound) so you can't go about powering anything with it. Of course if the FM Transmitter could operate over a wide range of variables then you could tap into power from the headphone jack and then the FM transmitter would only be on when sound was being produced. But that's just wishful thinking since the headphone jack will never be pushing more than a volt.

[GreyWolf Ghost]

Well I give you credit for wanting to try to build something like this.

However you could go to K-mart or Walmart and get the very basic of CD player adapter.

One that plugs into an audio device, then has a tape deck insert.

Heck I have even seen lower priced Jensen AM/FM CD player with audio in ( head phone size input on face plate).

Or for that matter, any brand Car deck that can play MP3 on disk.

It just seems like a lot of work to me. Good luck tho, I hope you build a good transmitter.

[James S]

[Presto]

[Cameron]

[James S]

[Cameron]