Found in an Electronics World of 1968 this circuit can use any SCR and diodes depending on the load. The circuit is full wave and the unijunction can be 2N2646.
This simple photometer uses a 0-200 µA galvanometer as indicator. The sensor is a common LDR and...
This circuit is from the Motorola Linear Databook of 1990 and can be implemented with other...
This circuit triggers a warning oscillator if you forget the lights on when you leave the car. The...