Precision power line transient generator

Claim 1

A testing circuit for applying a burst of alternating current voltage having a predetermined amplitude and time duration to an electrical device, such testing circuit including in combination: voltage supply means providing a continuous alternating current voltage at its output of known amplitude; rectifier means connected to the output of said voltage supply means and providing a continuous direct current output voltage in response to said continuous alternating current voltage; switch means having a switchable member and first, second and third terminals, said switch means making connection between said first and second terminals thereof if operated to a first position, said switch means making connection between said second and third terminals thereof if operated to a second position, said first terminal being connected to said output of said rectifier means; capacitor means connected between said second terminal of said switch means and a reference potential, said capacitor means being charged by said continuous direct current output voltage with said switch means operated to sAid first position thereof; relay means with control portion having a particular resistance and normally open switchable portion; first resistance means connecting said control portion to said third output terminal of said switch means; transformer means having primary and secondary windings with a selected turns ratio therebetween, said primary winding being connected in series with said voltage supply means and said switchable portion of said relay means, said secondary winding being connected to the device being tested; said first resistance means and said particular resistance of said control portion being selected such that with said switch means operated from said first position to said second position said capacitor discharges through said control portion thereby closing said normally open switchable portion for the predetermined time duration, said switchable portion thus applying said alternating current signal across said primary winding for the predetermined time duration; and said turns ratio of said transformer means being selected such that the voltage of a predetermined amplitude is applied for the predetermined time duration to the electrical device being tested.