Found in American documentation this circuit uses transistors of the time. The circuit can be made with current components. It works as a trigger working with 600 ohm signals.
Using bipolar, FETs and unijunction this long-lasting timer can reach 10 hours with good quality...
This 1-transistor circuit for currents up to 50 mA was found in the August 1974 Radio Electronics...
We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the...