How does alcohol detector work

Alcohol detector is a kind of instrument used to determine the alcohol concentration in human body. It is mainly used in the fields of safe driving, public place management and alcohol detection. Its working principle is mainly based on the gas sensing technology of alcohol.

How does alcohol detector work
How does alcohol detector work

Alcohol detector composition and working principle

Alcohol detector generally consists of alcohol sensor, control circuit, display and power supply system. Among them, the sensor is the most core component, its role is to detect the alcohol content in the exhaled gas. Common sensors are Semiconductor Alcohol Sensor and Infrared Adsorption Sensor.

The Semiconductor Sensor is a sensor based on a semiconductor gas-sensitive element, which is mainly used to detect changes in gas concentration. When the concentration of alcohol in the gas being measured increases, the resistance value of the semiconductor element changes. The detector determines the alcohol concentration by measuring this change in resistance value.

Infrared adsorption sensors, on the other hand, utilize the absorption properties of gas molecules of infrared light to determine the concentration of a gas. An infrared light source produces an infrared beam of a specific wavelength, which changes when the detector receives the infrared light after passing through the sample gas. The detector uses the change in light signal received by the detector to calculate the alcohol concentration.

In addition to the sensor, the control circuit is also an important part of the alcohol detector. The control circuit is mainly responsible for the connection between the sensor and the display, as well as the processing and display of the alcohol concentration. The control circuit is able to determine whether the tester has consumed too much alcohol through internal algorithms based on the alcohol concentration measured by the sensor, and display the results on the screen.

The power supply system is mainly used to provide power for the alcohol detector. Generally, the alcohol detector is powered by rechargeable batteries, which can be easily carried and used. After fully charged, the alcohol tester can be tested several times.

FS00700B (6)
Semiconductor C2H5OH Alcohol Sensor FS00700B

How to use alcohol detector?

When using an alcohol detector for testing, you need to follow the instructions for proper operation. Usually, the user needs to breathe into the sensor for some time to enable the sensor to detect the correct alcohol concentration. Once the test is completed, the alcohol detector will display the results based on the measured alcohol concentration.


Alcohol detectors also require regular calibration and maintenance during actual use. Since the sensors may fail or malfunction due to prolonged use, they need to be checked and replaced on a regular basis. In addition, the data of the alcohol tester also needs to be calibrated regularly to ensure the accuracy of the test results.