Found in RCA documentation from the 1970s, this circuit is intended for firing thyristors in inverter circuits. The components are from the era and the operating frequency is 10 kHz.
Very simple, this radio control circuit for short distances was found in an Electronic Design from...
This circuit is from a 1980's documentation for telecommunications. The circuit is used in SSB and...
When light fails to focus on the sensor, a common photo-transistor, the relay closes its contacts....