光敏电阻（Photosensitive resistance）.doc

光敏电阻（Photosensitive resistance） The photosensitive resistor is also called the photoconductive tube, and the commonly used materials are cadmium sulfide, as well as selenium, aluminum sulfide, lead sulphide and bismuth sulfide. These materials have characteristics of rapidly decreasing resistance to specific wavelengths of light. This is due to the light produced by the carrier are involved in the electric conduction, in the role of the applied electric field low drift motion, electronic toward the positive, of the power supply hole towards the power of the cathode, thus make photosensitive resistor resistance drops rapidly. composition Photoresistor is a resistor which is made from the photoconductive effect of the semiconductor with the intensity of the incident light, which is called photoconductive detector. The incident light is strong, the resistance decreases, the incident light is weak and the resistance increases. Edit this section role Photosensitive resistors are generally used in the measurement of light, control of light and photoelectric conversion (conversion of light to electricity). The commonly used photosensitive resistor sulfide cadmium photosensitive resistor is made of semiconductor materials. Photosensitive resistor of resistance change with the strength of the incident light (visible light), under the condition of dark, its value can be up to 1 ~ 10 m (dark), under the strong light condition (100 lx), its value (bright resistance), only a few hundred to thousands of ohm. The sensitivity of photosensitive resistor to light (that is, the spectral properties) is very close to the human eyes response to the visible light (0.4 ~ 0.76) mu m, as long as the light that the human eye can feel can cause its resistance to change. When designing the optical control circuit, it is easy to simplify the design by using incandescent bulb (small beads) light or natural light to control the light source. Edit this section specifications In general, photosensit