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.
Found in a 1980s telecommunications documentation, the circuit presented acts as a product...
This circuit was found in the Electronics Experimenter Handbook from 1991. The circuit controls a simple...
The time obtained in this circuit, from a 1978 publication, depends on R3 and C. R3 can have...