This circuit is from Radio Electronics from March 1977. The integrated circuit is from that time and the circuit is intended for an infrared audio link. The modulation is in pulse frequency.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
When the sensor receives light, the relay closes its contacts and remains so even after the light...
This circuit produces pulses of 90 V at intervals that can reach 5 minutes. The circuit is from a...