| 摘要 |
PURPOSE:To enable execution of a high-speed operation against an electrostatic surge being rapid and having a high voltage and to improve resistance to the surge by connecting a capacitor between the base and the collector of a transistor and by connecting a resistor between the base and the emitter thereof. CONSTITUTION:When an electrostatic surge being positive to a ground terminal 2 is impressed on a terminal 1, a peak current flows forward from the base of a transistor 3 to the emitter thereof through a capacitor 4, and by the transistor being put in continuity, the electrostatic surge is absorbed instantaneously. When the electrostatic surge remains further, an avalanche phenomenon occurs between the collector and the base of the transistor 3 in a subsequent period and this current flows through a resistor 5. Consequently a potential difference occurs between the opposite ends of the resistor 5, the transistor 3 is put in continuity and thereby the remaining electrostatic surge is absorbed. Thus, the capacitor 4 provided in approximation between the collector and the base of the transistor 3, an operating speed of a protective circuit can be improved, and by most of the electrostatic surge being absorbed, resistance to the surge can be improved. |
