本例中的电路可以用于测量光敏电阻型光耦的启动与恢复时间(图1)。这些光耦器件一般用于音频压缩器或音量控制电路。本设计使用了一只振荡的施密特触发器,在其反馈回路中有光耦DUT(待测器件)。光敏电阻与电阻R,构成一个分压器,控制施密特触发器的输入。光耦的LED连接到触发器的输出端。用示波器或数字万用表就可以测量输出脉冲的周期。负输出脉冲的周期等于开关导通时间,或启动时间。正脉冲 The circuit in this example can be used to measure the start-up and recovery times of photoresistor-type optocouplers (Figure 1). These optocoupler devices are typically used in audio compressors or volume control circuits. This design uses an oscillating Schmitt trigger with an optocoupler DUT (device under test) in its feedback loop. Photoresistor and resistor R form a voltage divider to control the Schmitt trigger input. The optocoupler’s LED is connected to the output of the flip-flop. Use an oscilloscope or digital multimeter to measure the period of the output pulse. The period of the negative output pulse is equal to the switch on-time, or start-up time. Positive pulse