What is a sensitive resistor

A sensitive resistor is a special resistor that is sensitive to analog quantities such as light intensity, pressure, and humidity. When selecting, not only should attention be paid to its rated power, maximum operating voltage, and nominal resistance value, but also to parameters such as maximum operating temperature and resistance temperature coefficient, as well as the direction of resistance change.

Characteristics of sensitive resistor types

At present, there are many types of sensitive resistors, including thermistors, photoresists, varistors, force sensitive resistors, magnetic sensitive resistors, humidity sensitive resistors, and gas sensitive resistors, which will be briefly introduced below.

1、 Thermistor. Thermistor is a type of resistor whose resistance value is very sensitive to temperature. This type of resistor is generally made of semiconductor materials such as single crystal and polycrystalline. There are many types, such as negative temperature coefficient thermistor whose resistance value decreases with temperature and positive temperature coefficient thermistor whose resistance value increases with temperature according to the temperature of the resistance value; According to the magnitude and rate of change of resistance with temperature; It can be divided into two types: slow variant and mutant variant; According to the way resistors are heated, they can be divided into two types: direct heating and side heating; According to their shape and structure, thermistors can also be divided into rod-shaped, circular, square, bead shaped, wire tube shaped, thin film and thick film thermistors. The main characteristics of thermistors are high temperature sensitivity, low thermal inertia, long lifespan, small size and simple structure. It is widely used in temperature measurement, control, fire alarm, meteorological sounding, microwave and laser power measurement and other fields.

2、 Photoresistor. A photoresistor is a type of resistive element made based on the principle of semiconductor photoelectric effect. Its resistance value can change with the intensity of incident light. A photoresistor is generally composed of a glass substrate, a photosensitive layer, electrodes, and other parts. According to the material used in the photosensitive layer, it can be divided into polycrystalline photoresists and single crystal photoresists. According to the spectral properties of photoresists, they can be further divided into ultraviolet photoresists, visible photoresists, and infrared photoresists. UV photoresistors are highly sensitive to UV radiation and can be used for detecting UV radiation; Visible light photoresists are mainly used in various photoelectric automatic control systems, including selenium, cadmium sulfide, cadmium selenide, zinc sulfide and other photoresists, which are generally used in various photoelectric automatic control systems.