Electronic touch switch for control purposes - has preamplifier, switching amplifier and triac triggering circuit

摘要

The triac is used for switching the load and when a contact surface is touched, an a.c. current of phase R is allowed to flow through a transistor and a resistor of high resistance to earth. The current is used to trip the transistor and it controls a switching amplifier, so that an N-channel JFET is tripped from its conducting to its non-conducting state; this removes the shunt from a capacitor in the triac trigger circuit, and a triac connects the load; several additional control points can be provided, containing only components necessary for the pulse tripping.