New high gain pulse-triggered power transistors with amorphous saturable CT cores

A new high gain pulse-triggered power transistor (PTPT) with amorphous saturable CT (current transformer) is presented. In the PTPT, a current transformer plays an important role in the astable multivibrator operation. The base of power transistors can be directly driven by the collector current through the current transformer. This positive feedback operation holds the on state of the power transistor by initiating the small trigger pulse to the primary winding of the current transformer. Turn off operation can be also achieved applying trigger pulse. This behavior corresponds to the so called GTO (GATE TURN-OFF THYRISTOR). A turn off technique is developed to extinguish the conducting power transistor. In this paper, the switching characteristics of PTPT and its experimental results are described. New applications using PTPT are also introduced.