| 摘要 |
PURPOSE:To protect an IC from a static electricity by a method wherein a resistor is connected between a base and an emitter and a collector is connected to a signal input terminal and the emitter is connected to the earthing terminal. CONSTITUTION:A surge voltage enters a terminal 1. At this time, if a resistor 8 is small, an avalanche current flows and if the resistor 8 is large, an avalanche breakdown is supressed. And further, when a slight leak exists between a base and an emitter, it causes a current amplified sharply with the current amplificarion ratio of a transistor being lead-in. Accordingly, if a capacitance of the resistor 8 is selected in approximately 10kOMEGA, it can sufficiently prevent a p-n junction from a breakdown due to an avalanche current and also, it can prevent a leak current between the base and the emitter from running, thus, protecting the IC from a static electric surge. |
