This circuit is from Ferranti documentation from 1967. The operational is of the time, but the configuration is valid for modern equivalent components, including higher current capacity.
This circuit is from Popular Electronics from the 90's. The circuit discharges the battery with a...
We found this time base circuit in a timer project from the August 1972 Radio Electronics...
This sonic switch, vox or sonic relay uses a Darlington of the time that has a gain of 10,000. The...