Photo resistor also known as the photosensitive resistor (photo resistor or light-dependent resistor, which is abbreviated as ldr) or light guide (photo conductor), commonly used in the production of materials for the cadmium, in addition to selenium sulfide, aluminum sulfide, lead and bismuth sulfide and other materials. The production of materials under irradiation with light having a specific wavelength, its resistance decreases rapidly characteristics. This is because the carriers are involved in conducting the light produced in the applied electric field drift motion testimony, the positive power electronics toward the hole toward the negative power supply, so that the light-sensitive resistor values to decline rapidly.
Photo resistor is a resistance value of the strength of a photo conductive effect using a semiconductor made with the incident light changing resistors, also known as a photo conductive detector; incident light intensity, the resistance is reduced, the incident light is weak, the resistor increases. Still another of the incident light is weak, the resistance is reduced, the incident light intensity, resistance increases.
Photo resistor are generally used for measuring light, light control and photoelectric conversion (to change light into electricity changes). Conventional photosensitive resistor CdS photo resistor, which is made of a semiconductor material. Photo resistor light sensitivity and visible light (0.4 ~ 0.76) μm of the response of the human eye is very close, as long as the human eye can feel the light, will cause its resistance changes. When designing the light control circuit, all with incandescent bulbs (small bulbs) light or natural light for controlling the light source, so that the design greatly simplified.
