We found this touch control on a Popular Electronics from 1970. The circuit makes use of an integrated of the time. It can be adapted to use modern equivalent components.
Based on an Analog Devices LTC1540, this circuit consumes only 50 uA, serving to monitor the...
This circuit was found in a 1980s documentation. The diodes may be general purpose diodes such as 1N34...
We found this digital timer circuit in a 1994 publication. The power is supplied by 12 V, which is the...