Synchronous comparator tripping device - operating on rectified AC supply is applied to static relay and has Zener diode

摘要

A comparator-tripping device is used which operates on rectified AC in a synchronous manner and which provides a signal when an impedance bridge is out-of-balance. The first diagonal of the bridge (HG) is connected to the rectified ac supply. A thyristor (30) and a threshold device, e.g. a Zener diode (31), are connected in series in the first diagonal (HG) while the cathode and gate of this thyristor are connected to the terminals of the second diagonal (EF). A diode (32) is connected between the cathode and gate of the thyristor (30). The device may be used in a static relay. One arm of the impedance bridge comprises a resistance which varies as a function of an external physical stimulation.