Photodiode Light Detector

This light detector is a current-to-voltage converter. The FET input op-amp prevents the loading of the photodiode and the voltage at the output is proportional to the current in the photodiode. So long as the photodiode response to the light is linear, the output voltage is proportional to the light falling on the photodiode. 这个光探测器是一个电流-电压转换器。运放的FET输入可以防止光二极管的负载，输出电压与光二极管中的电流成正比。只要光二极管对光的响应是线性的，输出电压就与照射在光二极管上的光成正比。

Photodiodes

A photodiode consists of an active p-n junction which is operated in reverse bias. When light falls on the junction, a reverse current flows which is proportional to the illuminance. The linear response to light makes it an element in useful photodetectors for some applications. It is also used as the active element in light-activated switches.

Photodiode

The mechanism of the photodiode is like that of a (miniaturized) solar cell. Their response time is fast, on the order of nanoseconds. As light detectors, they are reverse biased - the reverse current is linearly proportional to the illuminance striking the diode. They are not as sensitive as a phototransistor, but their linearity can make them useful in simple light meters. 光电二极管的原理类似于(微型化的)太阳能电池。它们的响应时间很快，大约在纳秒量级。作为光探测器，它们被反向偏置——反向电流与击穿二极管的光照度成线性比例。它们的灵敏度不如光 transistor，但其线性特性使其在简单的光度计中很有用。

Photodiode Characteristics

Photodiode Characteristics

The reverse current through a photodiode varies linearly with illuminance once you are significantly above the dark current region.