carbon monoxide will endanger our human health. if carbon monoxide poisoning is severe, it will cause death. when we use carbon monoxide detector to detect the change of carbon monoxide concentration, we mainly convert the carbon monoxide gas in the air into an electrical signal through the sensor. after circuit conversion processing, the concentration of carbon monoxide gas is displayed by LED, and this signal is converted into a current or frequency signal and sent to the secondary instrument, realize remote monitoring. Therefore, in this process, the principle of carbon monoxide detector will be involved. So do you know how the CO detector works? The following is a brief introduction by yi yun Tian:

principle of carbon monoxide detector:

1. Electrochemical Principles

When carbon monoxide diffuses into the gas sensor, its output produces a current output, which is provided to the sampling circuit in the alarm, and plays a role in converting chemical energy into electrical energy. When the gas concentration changes, the output current of the gas sensor of the carbon monoxide detector is also proportional to the change.The principle of electrochemical sensor is that two electrodes are immersed in a conductive solution (electrolyte), and carbon monoxide molecules react with water molecules on one of the electrodes to convert into dioxide Carbon and produce hydrogen ions and electrons, this electrode is the working electrode (W); and the product of the change is transferred to another electrode, which reacts with the oxygen on this electrode to regenerate water molecules, which is the counter electrode. (C); The two electrodes are conducted through an external circuit containing a resistor, and the change in voltage across the resistor can be measured; therefore, the resulting reaction is to convert carbon monoxide into carbon dioxide in the presence of oxygen. The electrochemical principle of carbon monoxide detector is mainly used in industry or where the accuracy is relatively high, and its detection accuracy is high.

2, semiconductor principle

semiconductor principle refers to the detection of carbon monoxide with semiconductor sensor. when carbon monoxide is detected with carbon monoxide detector, the semiconductor resistance becomes smaller (semiconductor N-type element), mainly due to the increase of carrier electrons in the element, and the concentration and proportion of the display are related to the type of semiconductor sensitive element. Using the principle of semiconductor carbon monoxide detector is generally used in the civilian industry, the detection accuracy is low.

3. Infrared principle

Infrared principle is designed based on the 1 principle of selective absorption of infrared rays by different gases. Adopt foreign advanced correlation filtering technology (GFC). The carbon monoxide detector has two built-in analysis edges, sharing a gas chamber. The signal spectrum of cross analysis is used as a reference signal while the signal to be measured is subtracted through a digital logic circuit to obtain the signal change of the measured gas. At this time, the magnitude change of the signal concentration is the gas concentration value. The signal is converted into a voltage signal, amplified by gain, and linearized by microcomputer 20 segments of data, finally through the display shows the accurate concentration of gas. The principle of infrared carbon monoxide detector is generally suitable for large range of places, high detection accuracy, life of up to 10 years.

In summary, we can see that under normal circumstances, the gas sensor of the carbon monoxide detector mainly uses semiconductor principles, infrared selective absorption principles and electrochemical principles. However, due to the electrochemical carbon monoxide gas sensor and other principles of carbon monoxide gas sensor compared to the sensitivity of High, simple structure, low power consumption and safety performance, therefore, the gas sensor of carbon monoxide detector adopts electrochemical principle is very extensive.