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.
The presented differential amplifier, indicated for instrumentation, was obtained in the 1994...
This circuit provides a signal when dialing occurs. The circuit is powered by the telephone line...
This circuit uses two TTL trigger inverters to generate signals that can be adjusted at R1. The...