This buzzer trigger can be used for small alarms. We find it in an 80’s American documentation. The supply can be done with voltages from 3 to 18 V.
The output of this circuit can be a crystal phone or a piezoelectric capsule. The circuit tests the...
This circuit was obtained in an English publication of 1977. The operational is of the type with...
This circuit was found in a Poptronics of the 90's. It can be powered by voltages between 6 and 15...