This circuit was found in an Elektor from the 90s. Next to the circuit we have a table with the delays obtained when the circuit is connected according to the positions of the selector switches.
In the figure we show how to use an old portable AM or FM radio as a test amplifier or signal...
Among other applications, the 1960 Sylvania transistor manual indicates this timer for chess...
This circuit for voltmeter has an output of 1 V for 100 uA having been suggested by American...