This circuit from Motorola is from 1968, appearing elsewhere on this site. The transistors admit equivalent and the relay is of the sensitive type for low voltage, according to the power supply.
This passive circuit was found in the March 1995 issue of Elexctonics Now magazine. The circuit is for...
This circuit was found in an ancient American documentation. Used integrated circuits are uncommon...
Using the 555 and 4020, this timer was found in the July 1994 Radio Electronics magazine. The...