This circuit responds to frequencies from 100 Hz to 3 MHz. We find it in a 90s Radio Electronics. Transistors are general purpose types.
This circuit deactivates devices powered by the power grid so that when the power returns, they do...
The trigger signal for this circuit is an audio tone. Tones up to close to 100kHz can be used. The...
Found in the March 1974 Radio Electronics magazine, this circuit is designed to measure the level...