This 80's circuit has been winning. It is a 1 000 gain sample and hold circuit and an offset current setting. The configuration can be adapted to operate with modern equivalent components.
This additional bell circuit was found in the February 1994 Electronics Now magazine. The...
A delay of a few seconds to a few tens of seconds can be achieved with this circuit found in a...
This circuit uses a transistor to trigger the alarm from a low quiescent current sensor. The relay...