This circuit shows how to use an ordinary LED as a light sensor. It makes use of the photovoltaic voltage developed across the LED when it is exposed to light. LEDs are cheaper than photodiodes and ...

我们知道，一个动圈式的电磁扬声器，既可以播放声音，也可以作为麦克风来检测声音。同样，一个直流电机可以将电能转换成动能，也可以将动能转换成电能。那么一个LED是否也可以将光转化成电信号，进而可以当做光电传感器呢？ 为什么提出这个问题？

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Here is one simple circuit of a general-purpose white LED security light with Passive Infrared (PIR) Motion sensing mechanism. At the heart of the circuit is a PIR sensor module SB0061. SB0061 is a ...

Ikea has launched a new motion-sensor LED night light in Europe. It runs on one AAA battery, detects movement within 3 metres and is currently available in select European countries for €2.99. UK and ...