How do tvoc Sensors Work?

PID tvoc sensor:

PID tvoc sensor working principle

PID uses an ultraviolet light (UV) light source to ionize organic molecular ion (ionization) that can be detected by detectors. The detector capture the positive and negative charges of ionized gas to transform it into a current signal to measure the gas concentration. When the gas absorbs high -energy ultraviolet light to be measured, the gas molecules are temporarily lost by the inspiration of ultraviolet light to become ions with positive charge. After the gas ion is detected on the electrode of the detector, the electrons will soon form the original gas and steam molecules. PID is a non -broken detector that does not change the gas molecules to measure the gas. Gas detected by PID can still be collected for further measurement.

Features: fast response, many detection gas, simple design, easy maintenance

Semiconductor principle tvoc sensor

When this type of sensor detects the measured gas, its conductivity will change accordingly. With the increase and decrease of the concentration of the measured gas, the conductivity will increase and decrease. After the circuit outputs the information, the detection value of the tvoc can be obtained.

Advantages: cheap and long life

Disadvantages: Poor consistency, poor stability, slow response time, and less VOC gas types that can be detected.