| 摘要 |
<p>PURPOSE:To ensure the variation of the hysteresis in a simple and indepenedent way by providing the transistor to cut off the current flowing to the feedback circuit when the power voltage lowers less than the fixed level. CONSTITUTION:The collector of NPN transistor RT1 is connected to the base of PNP transistor TR2, and feedback circuit R7 is connected between the emitter of TR2 and the emitter of TR1. Thus, a Schmitt circuit is formed. Furthermore, feedback circuit R9 is connected between the collector of TR2 and the base of TR1, and transistor TR3 is added to cut off the current flowing to circuit R9 when the power voltage lowers less than the fixed level. As a result, the hysteresis can be varied in a simple and independent way.</p> |
