Found in Popular Electronics from the 90s, this circuit turns off an appliance at the end of the programmed time. The 12 V relay must have contacts according to the controlled current.
With the name of detectaphone, we find this circuit in a documentation from 1966. It will be...
It can be obtained from Mouser Electronics new TPS54A20 Texas Instruments consisting of step-down...
This interesting 80's EDN circuit divides the input pulse frequency by a number given by n...