This circuit is from a 1980s Motorola documentation. The circuit can be set to fire from 60 to 120 V DC or from 42 to 84 V AC. The circuit has a forehead button that activates an indicator lamp.
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...