This 40-second delay switch was found in a 1965 Electronic Design. The unijunction transistor might be the 2N2646 and the SCR a sensitive modern equivalent.
This circuit acts on the dynamic range of an audio signal, which can be useful for recording,...
This is the conventional application of the UCN4202 to control a 12 V stepper motor with current...
Described in the December 1969 Radio Electronics magazine, this circuit is intended to supply the...