The purpose of this circuit is to improve a trigger circuit using a zener diode. The circuit was found in an American documentation from 1964. It can be improved using equivalent modern 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...