This circuit activates a relay after a time given by C1 and R1. The circuit is from a Radio Electronics from December 1974. The relay voltage is the same as that used in the power supply.
In a microprocessor project (shield) for control applications, a triggered clock can be useful....
Another alternate action switch that uses a NAND Schmitt Gate [4093 IC] is shown here. The...
This circuit was found in a 1968 EEE and can be implemented with any current general-purpose transistor....