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, from the 90's, is intended for operation with vinyl record players of the time, as...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...