This circuit serves as an audio output for AM or even FM radios and was found in a Radio Electronics magazine from March 1990. Note the supply voltages.
The presented circuit uses an optocoupler to trigger a triac. We found it in a Popular Electronics from...
This circuit turns on incandescent lamps (do not use any other type) when it gets dark. The...
This circuit shows how to use the TTL IC 7790 to divide a square TTL signal by 7. Duty cycle is...