This timer with two unijunction transistors and one SCR was found in an American documentation from 1964. The unijunction transistors could be the 2N2646.
This circuit trips when a negative pulse is applied to its input or when the voltage drops below a...
This is an old 1988 circuit consisting of a timer or time control for exposing silk-screen arrays. The...
This circuit was taken from an old American documentation. It can be built with modern op amps. The...