This circuit activates a garage door by the car headlights car or a lantern. The circuit is from a 1967 documentation, making use of period components.
This circuit using components that are still common in our market was found in a 1987...
The varactor or varicap diode tunes the signal for listening to SSB signals on a common receiver. The...
This circuit that also serves to control LEDs and other loads is from a 1960 publication. The...