# Is this possible?

1. Feb 15, 2012

### thorguy57

Ok first off I am sorry because this probably isn't in the right section but didn't know where to put it. I have to come up with a report in one of my classes about power distribution. I am just curious if this would work theory wise. I am not going to make a working model or anything this is more just an assignment to learn how to brainstorm.
Ok so here it goes. Would it be possible to transmit small amounts of power through radio waves? My this I mean is it possible to have a speaker hooked up to an electrical source which cause the first speaker to vibrate back and forth rapidly (like a normal speaker does). You would then put another speaker in front of it. The pressure of the radio waves would then make the other speaker fluctuate back and forth and move a core back and forth through some windings to create a voltage. I would mount both speaker inside a closed, sealed bow to contain the sound waves. Would this be at all possible do you think?

2. Feb 15, 2012

### nasu

What you describe (with the two speakers) is power transmitted through sound waves and not radio waves.
The speaker produces mechanical waves which are detected by the second one (acting like a microphone).

Regrading the original question, sure is possible. This is how radio and TV broadcasting work. The receiver gets a (very) little amount of power transmitted from the emission antenna through radio waves. Here the focus is not on the power per se, but the information contained in the radio wave. However the principle works.
However to transmit large power this way (as a substitute for power lines) is impractical for several reasons. It may be used though in some special cases.

3. Feb 15, 2012

### thorguy57

Thanks for the quick response. Yes sound waves, sorry. I really should start proof reading before I submit. Like I said this is more just for a brainstorming thing. Maybe I will try and build one of these things just as a little experiment when I get bored. I wouldn't think it should be to hard. Just two speakers pointed at each other in a completely sealed plexiglass box. That way the pressure of the sound waves are directed directly at the other one. If I could get the one speaker to fluctuate the other one enough to build up a charge in a coil hooked to it and light an LED I would be happy. Thanks again.

4. Feb 15, 2012

### Drakkith

Staff Emeritus
As Nasu explained you would have energy (and thus power) transferred through sound waves, not radio waves. However I would like to point out that ALL waves move energy around. The very act of receiving a radio signal is a direct result of the radio waves transmitting energy into the antenna to move the electrons back and forth.

Also, your method of one speaker sending waves to another speaker is almost identical to the way a normal microphone works. The waves in the air cause a coil or other object to vibrate and generates a voltage in the circuit of the microphone which is amplified and sent to a speaker or recording device.