Photoresistor applications are very wide now. Today we will have a closer look at photoresistors.
Photosensitive resistor is a special resistor made of semiconductor materials such as sulfurization barrier or selenidation barrier. Its surface is also coated with moisture-proof resin, which has photoconductivity effect.
Photoresistors are very sensitive to light. The stronger the light, the lower the resistance. With the increase of light intensity, the resistance value decreases rapidly, which can be reduced to less than 1KΩ.
The working principle of photoresist is based on the internal photoelectric effect, that is to say, electrode leads are installed on both ends of semiconductor photosensitive materials, which are packaged in the shell with transparent window to form the photoresist. In order to increase the sensitivity, the two electrodes are often made into comb shape.
Here are the photoresistor appliccations:
1. The photoresist module is the most sensitive to the ambient light intensity, which is generally used to detect the brightness and light intensity of the surrounding environment.
2. When the module has no light or the light intensity can not reach the set threshold, the do port outputs high level. When the external environment light intensity exceeds the set threshold, the module D0 outputs low level.
3. The small board digital output D0 can be directly connected with the single-chip microcomputer to detect the high and low levels, thus to detect the change of the light intensity of the environment.
4. The analog output AO of small board can be connected with AD module. Through AD conversion, more accurate value of ambient light intensity can be obtained.