This simple latching alarm circuit using CMOS gates was found in the May 1990 Radio Electronics magazine. The supply voltage is dependent on the relay.
This circuit was found in the October 1989 issue of Radio Electronics magazine. It drives an...
The transistors in this circuit from an English publication in 1980 may be the BC548. Operational...
This is one of many circuits of this type that can be found in this section. This one is taken from...