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.
This is the power supply for the amplifier in the previous circuit. We found it in the same Radio...
This circuit was found in an American publication from the 1980s. It can be made with most current...
This nonlinear gain circuit was found in a 1965 Electronic Design. The configuration can be used...