This 3-transistor buzzer or buzzer is a classic type found in the July 1998 issue of Electronics Now magazine. The power rating depends on the output transistor.
This circuit is used to obtain the synchronized activation of a mechanical battery clock. The...
ON Semiconductor Phototransistor Output Optocouplers Available from Mouser Electronics is the...
Found in an Electronic Design from the 80's, this circuit monitors a three-phase line, activating a...