Surge Analysis of the Free-Running Transistor Inverter

The collector current surge of the free-running transistor inverter is investigated. In this circuit, the collector current increases sharply with saturation of the core. This spike is undesirable with respect to the reliability of transistor and the efficiency. Since the generation of spike, however, brings about the commutation, we can not avoid this phenomenon. The details of its generation mechanism is unknown, so the relation between its magnitude and the constants of circuit is analyzed by using a simplified pi model of transistor.