For signals up to about 500 kHz modulated in amplitude and transmitted by the power network, the figure shows the receiver. The circuit is from a Radio Electronics from February 1989.
This circuit is from a 1968 General Electric manual. It produces a pulse of light when fired,...
This circuit is from a 2001 Poptronics. The magazine no longer exists, but the components used are...
This circuit is from 1990 documentation. It uses a bridge with LEDs and the potentiometer must be...