Using the 555 and 4020, this timer was found in the July 1994 Radio Electronics magazine. The relay is voltage-dependent, and the transistor is general purpose.
This circuit was found in a 1964 Electronic Design. The circuit makes use of transistors of the...
This circuit was found in Motorola documentation from 1968, using high power transistors and...
This circuit was found in a RE Experimenter Handbook from the 90's. The components are of the...