摘要 |
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 (Ic). In order to ameliorate problems due to stray inductance a third transistor (Q3) provides a shunt path for the base current (IB1) and accumulated base carrier charge from the base (B1) of the bipolar transistor (Q1) to the source (S) of the field effect transistor (Q2), the third transistor (Q3) being switched ON via a capacitor (CA) in response to an increase in voltage at the base (B1) when the field effect transistors (Q2) is switched OFF by means of signal eG. A further capacitor and zener diodes may also be provided to limit peak voltage due to said stray inductance. |