Found in an American documentation from 1968, this circuit uses transistors from the time. The circuit can be adapted to use equivalent modern components.
This signal injector circuit, an astable multivibrator, was found in a 1971 magazine. The circuit can...
This circuit that can only be used with simple resistive and inductive loads (never electronic) was...
This circuit activates a relay at dawn. The relay can be used to sound an alarm, turn on a radio...