Methods for reducing the forward voltage drop in pseudospark switches

The paper describes the methods, which can be used in the pseudospark switches to decrease the forward voltage drop in initial glow stages of the discharge burning. The main direction of reducing the discharge burning voltage is a use of a special design of the electrode system and a special design of the cathode cavity. In the TPI switches, a so-called high-emissivity cylinder is placed at the bottom of the cathode cavity. The basic component of the cylinder is the tungsten powder (90 percent) to which aluminium oxide and caesium carbonate are added. Thus, this composite material contains caesium, which plays the principal part in decreasing the discharge burning voltage. Correspondingly, the decrease in the forward voltage drop allows the TPI switches to commute the anode voltage starting from 1 kV. In the TDI switches an idea of artificial initiation of the cathode spot is used. This can be achieved due to a special trigger circuit. Then the forward voltage drop is decreased to 200-300 V.