| 摘要 |
PURPOSE:To carry out a detection of voltage, by connecting the two transistors with the resistance having a parasitic transistor and making use of the connecting voltage between the collector and the emitter of a parasitic transistor. CONSTITUTION:The voltage is applied to the terminal B with the terminal A opened, and the base voltage is applied to the terminal C. The transistor 9 performs just an amplifying action while the voltage applied to the terminal B is within a range of a proper value. When the voltage of the terminal B increases to exceeds the Zener voltage of the parasitic transistor Q which is caused between the resistance 8 and the ground, most of the current applied to the terminal B flows to the transistor Q. Thus the amplifying action is lost for the transistor 9. Thereafter, the voltage is applied to the base of the transistor 7 to secure a state of conduction. As a result, the potential at one end of the resistance 8 approximates to the ground potential to eliminate the parasitic transistor Q. Thus the amplifying action is recovered for the transistor 9. |
