在汽车等交通工具自动变速装置的电子控制器中，都是用白炽灯来指示电源工作状态和故障等。驾驶员难以确定，因为指示灯常因过流而烧坏。因此，必须对灯的输出电流加以控制，一般都采用保护电路进行限流。图１是一种通用的灯过流保护电路，该电路利用浪暗电流通过使用电阻ＲＩ In the automotive and other automatic transmission vehicle electronic controller, are used to indicate incandescent power status and fault. Pilot difficult to determine, because the light is often due to over-current and burn out. Therefore, the output current of the lamp must be controlled, and the protection circuit is generally used for current limiting. Figure 1 is a common lamp over-current protection circuit, which uses the dark current through the resistor RI