PM2.5 sensor is a particulate matter sensor, also called a dust sensor. it is a photoelectric sensor that detects air through the principle of laser beam scattering. Photoelectric sensors are a category of sensors. According to the working principle, there are many other classifications of sensors. Below, the Luftmy editor will introduce the detailed classification of sensors to you.

There are many classification methods for sensors, but two commonly used methods are: one is based on the measured physical quantity; the other is based on the working principle of the sensor. Common sensors classified by measured physical quantity include: temperature sensors, humidity sensors, pressure sensors, displacement sensors, flow sensors, liquid level sensors, force sensors, acceleration sensors, torque sensors, micro-dust sensors, etc.

Sensors can be classified according to their working principle as follows:

1. Electrical Sensors

Electrical sensors are widely used in non-electrical electrical measurement technology. Common ones include resistive sensors, capacitive sensors, inductive sensors, magnetoelectric sensors, and eddy current sensors.

Resistive sensors are made using the principle of using a rheostat to convert the measured non-electrical quantity into a resistance signal. Resistive sensors generally include potentiometer type, contact rheostat type, resistance strain gauge type, and piezoresistive sensors. Resistive sensors are mainly used for the measurement of parameters such as displacement, pressure, force, strain, torque, airflow velocity, liquid level, and liquid flow.

Capacitive sensors are made using the principle of changing the geometric size of the capacitor or changing the properties and content of the medium, thereby changing the capacitance. They are mainly used for the measurement of parameters such as pressure, displacement, liquid level, thickness, and moisture content.

Inductive sensors are made by changing the geometric size of the magnetic circuit or the position of the magnet to change the inductance or mutual inductance, or based on the piezomagnetic effect principle. They are mainly used for the measurement of parameters such as displacement, pressure, force, vibration, and acceleration.

Magnetoelectric sensors use the principle of electromagnetic induction to convert the measured non-electrical quantity into an electrical quantity. They are mainly used for the measurement of parameters such as flow, speed, and displacement.

Eddy current sensors are made using the principle that a metal moving in a magnetic field cuts magnetic field lines, forming eddy currents within the metal. They are mainly used for the measurement of parameters such as displacement and thickness.

2. Magnetic Sensors

Magnetic sensors are made by utilizing some physical effects of ferromagnetic substances and are mainly used for the measurement of parameters such as displacement and torque.

3. Photoelectric Sensors

Photoelectric sensors play an important role in non-electrical electrical measurement and automatic control technology. They are made using the photoelectric effect of photoelectric devices and optical principles, and are mainly used for the measurement of parameters such as light intensity, luminous flux, displacement, and concentration.

4. Potential-type Sensors

Potential-type sensors are made using principles such as the thermoelectric effect, photoelectric effect, and Hall effect. They are mainly used for the measurement of parameters such as temperature, magnetic flux, current, speed, light intensity, and thermal radiation.

5. Charge Sensors

Charge sensors are made using the piezoelectric effect principle and are mainly used for the measurement of force and acceleration.

6. Semiconductor Sensors

Semiconductor sensors are made using principles such as the piezoresistive effect, internal photoelectric effect, magnetoelectric effect, and material changes produced by contact between semiconductors and gases. They are mainly used for the measurement of temperature, humidity, pressure, acceleration, magnetic fields, and harmful gases.

7. Resonant Sensors

Resonant sensors are made using the principle of changing electrical or mechanical natural parameters to change the resonant frequency. They are mainly used to measure pressure.

8. Electrochemical Sensors

Electrochemical sensors are based on ionic conduction. According to the different formation of their electrical characteristics, electrochemical sensors can be divided into potentiometric sensors, conductometric sensors, coulometric sensors, polarographic sensors, and electrolytic sensors. Electrochemical sensors are mainly used for analyzing the components of gases, liquids, or solids dissolved in liquids, as well as the measurement of parameters such as pH, conductivity, and oxidation-reduction potential of liquids.

In addition, according to the signal detection and conversion process of the sensor, sensors can be divided into two categories: direct conversion sensors and indirect conversion sensors. The former converts the non-electrical quantity input to the sensor into an electrical signal output in one go. For example, when a photoresistor is exposed to light, its resistance value changes, directly converting the light signal into an electrical signal output. The latter first converts the non-electrical quantity input to the sensor into another non-electrical quantity, and then converts it into an electrical signal output. Pressure sensors made of Bourdon tube sensing elements belong to this category. When pressure acts on the Bourdon tube, the tube deforms, and the sensor then converts the deformation into an electrical signal output.