摘要 |
<p>A composite transistor comprising a cascade arrangement of a bipolar transistor (Q1) and a field effect transistor (Q2) serves to control supply of a load current (I). In order ameliorate problems due to stray inductance an auxiliary transistor (Q3) provides a shunt path for the base current (IB1) an accumulated base carrier charge from the base (B1) of the bipolar transistor (Q1) to the source (S) of the field effect transistor (Q3), the auxiliary transistor (Q3) being switched ON via a zener diode (ZD3) in response to an increase in voltage at the drain of the field effect transistor (Q2) when the latter is switched OFF by means of signal eG. A further zener diode may also be provided to limit peak voltage at the collector of the bipolar transistor (Q1). </p> |