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 monitors the state of a 12 V battery and can be used directly with one, or even in a...
Other operational amplifiers series, such as MC34072, MC34074, MC35071, MC35072, MC35074 d MC33071...
This circuit generates signals that can be adjusted in a small range around the frequency of the...