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 is suitable for applications in medical, research and industrial equipment. The...
This circuit, found in a publication of the year 1968, uses a transformer to drive two power...
This 100-second timer was found in a 2000 Poptronics. The magazine no longer exists, but the...