--- In quizbowl_at_yahoogroups.com, jp_lien <no_reply_at_y...> wrote:
> Dude, what the hell are you talking about? Seriously, this makes
no
> sense at all.
Oh really? Ever build a crystal radio?
http://home.gwu.edu/~ers/remotebuzzer.png
The upper-right circuit (L1R1C1) broadcasts a carrier wave of
frequency f1. The upper-left circuit has resonant frequency f1, and
so an alternating current is induced in it. That induced current
itself induces a current through the transformer Z1 in the lower-
left circuit, if the switch S1 is closed. The alternating current in
L3R3C3 creates a carrier wave with frequency f3, which induces a
current in the lower-right circuit. The rest rectifies the current,
and uses that rectified signal to regulate an op-amp, which turns on
LED D5.
Edmund
