In this circuit the triac conducts when switch S1 is opened. We found it in the October 1987 Radio Electronics magazine. The triac is controlled according to the load.
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...