| 摘要 |
PURPOSE:To prevent damage of a common drive transistor by connecting a Zener diode having a Zener voltage larger than a maximum rated voltage between the collector and the emitter of the transistor and smaller than a power source voltage in parallel with the transistor. CONSTITUTION:A Zener diode 22 having a Zener voltage larger than a maximum rated voltage between the collector and the emitter of a common drive transistor 2 and smaller than a power source is connected in parallel with the transistor 2 so that a voltage larger than the Zener voltage is not applied to the transistor 2. Thus, the damage of the transistor 2 is eliminated without connecting the diode between the collector of the transistor 2 and a ground and without applying a counterelectromotive force generated at the time of switching OFF to the transistor 2. |
