This circuit consists of an improved version of the CIR5892, using two transistors and adjusting the operating point. The transistors can be the BC548.
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...