Several years ago I attended a program for science teachers in which I made a simple device that consisted of a pencil on which was placed a rare earth magnet and around which were wrapped about 300 turns of fine copper wire. When the two wire ends were connected to a plug which fit into a transistor radio, and one placed the pencil in one's mouth, the radio could be heard playing in one's head! Also if someone else placed their ear against my ear, they could also hear the radio playing.
I tried to make this again using a cheap transistor radio, but could not hear a thing. I have been told that the problem might be that newer radios have an output that is too weak to activate the pencil speaker. I bought a tiny audio output transformer from RadioShack today, hoping to somehow boost the signal, but I'm not sure this is the right device, or precisely how I should connect this. If anyone reading this has any suggestions or insights, I'd be most appreciative.
Thanks
I tried to make this again using a cheap transistor radio, but could not hear a thing. I have been told that the problem might be that newer radios have an output that is too weak to activate the pencil speaker. I bought a tiny audio output transformer from RadioShack today, hoping to somehow boost the signal, but I'm not sure this is the right device, or precisely how I should connect this. If anyone reading this has any suggestions or insights, I'd be most appreciative.
Thanks