The main parameters and characteristics of photosensitive resistance are as follows:
1. Bright resistance in the photocurrent state
Under a certain applied voltage, the current flowing through the photoresistor when light is irradiated is called the photocurrent, and the ratio of the applied voltage to the photocurrent is called the bright resistance, which is usually expressed as "100LX".
2. Dark resistance under dark current state
Under a certain applied voltage, the current flowing through the photoresistor when there is no light is called dark current. The ratio of the applied voltage to the dark current is called the dark resistance, which is usually expressed as "0LX".
Sensitivity refers to the relative change value of the dark resistance when the photoresistor is not irradiated by light and the light resistance when irradiated by light.
4. Illumination characteristics of photoresistor
The relationship between the photocurrent and luminous flux of the photoresistor under a certain applied voltage. Different types of photoresistors have different illumination characteristics, but the illumination characteristic curves are all nonlinear. Therefore, it is not suitable for quantitative detection, which is the shortcoming of photoresistor. Generally, it is used as a photoelectric switch in automatic control systems.
5. The spectral characteristics of the photoresistor are related to its material.
The vulcanized photosensitive resistance has high sensitivity in a wide spectrum range, with the peak value in the infrared region; the peak value of cadmium sulfide and cadmium selenide is in the visible light region. Therefore, when choosing a photoresistor, the material of the photoresistor and the type of light source should be considered together in order to obtain satisfactory results.