I mostly avoided the siren song of the 555 timer that seemed to echo through the blogiverse during the recent 555 contest, but when I was out and about last weekend, I picked up 10 of them from Anchor Electronics, and they have been taunting me from the shelf ever since. So, last night I dug out some resistors and caps, and tossed together a simple multivibrator circuit. Today, I was pondering what I could do with it, and I recalled seeing the circuit being used as an AM transmitter. The basic idea is to simply AC couple the audio onto pin 5, and voila. So… that’s what I did!

I’m actually not quite sure I completely understand how this works (it’s not entirely clear to me whether it is more accurate to call this pulse width modulation or frequency modulation) but the circuit does work. I imagine that once I understand it better, I’ll be able to make it work significantly better. But that’s something for the future.