Indicated for activation by microcontrollers, this circuit was found in the Radio Electronics magazine of December 1987. The MOSFET can be of any type according to the buzzer.
These circuits from a May 1994 Electronics Now take advantage of the noise from the junctions of...
This circuit is powered by 1.5 V and has a long lifespan as it consumes only 320 uA. The circuit is...
This is a circuit of the 80's ON Semiconductor thyristor manual. Of course, the configuration can be...