A new trigger circuit for closing a switch

An electronic device is described for controlling the closing of a relay or switch at a predetermined point on the wave form of an a-c source. Current (or closing the relay is controlled by a gas filled triode, the firing of which is obtained by the distorted wave of a multivibrator. The output of the multivibrator is made to change phase with reference to the a-c voltage wave. The device is useful for the study of transients.