The handheld alcohol detector can be used to confirm whether the driver has drunk driving behavior. Why can one detect the alcohol content in one breath? A small alcohol detector can be asked by the university!
Normally, the detected driver exhales at the alcohol detector for more than 2.5 seconds, and the law enforcer only needs to observe the change of the instrument value to make a preliminary inference about whether the tested person is drunk or drunk. This is because the alcohol detector is equipped with an alcohol gas sensor, which is equivalent to a gas-sensitive resistor, and the resistance value will change with the change of the alcohol concentration in the exhaled gas of the person, thereby causing changes in the current and voltage in the circuit. The alcohol content in the exhaled breath has a certain proportional relationship with the alcohol content in the blood. Different concentrations of alcohol content will cause the sensor to generate voltage signals of different strengths. Finally, the signal is amplified by an electronic amplifier, and the data on the alcohol detector is obtained. .
The breath alcohol tester is developed from the original drunk tester, tester and portable drunk tester. The first breath alcohol detector was developed as early as 1954. Since then, the breath alcohol detector began to develop rapidly, and at the same time, the alcohol sensor technology is constantly improving.
At present, there are five main sensor technologies used in commonly used breath alcohol detector products, which are semiconductor detection technology, fuel cell technology, colorimetric technology, infrared detection technology, and gas chromatography analysis technology. For various reasons, fuel cell type technology and semiconductor testing technology are the most commonly used at present.
Fuel cell type breath alcohol detector uses fuel cell alcohol sensor as gas sensor. The fuel cell alcohol sensor uses platinum as the electrode. The combustion chamber of the sensor is filled with a special catalyst, which can fully burn the alcohol entering the combustion chamber and convert it into electrical energy. It will also generate a voltage on the two electrodes. This voltage and the alcohol entering the combustion chamber gas The concentration is proportional.
The semiconductor sensor breath alcohol detector generally uses a tin oxide semiconductor sensor. When the concentration of the sensitive gas in the measured gas increases, the gas-sensitive characteristics of the tin oxide semiconductor sensor will cause the resistance value to decrease.
The production cost of the fuel cell type breath alcohol detector is higher, but the performance is stronger than that of the semiconductor sensor. Alcohol detectors that use different technologies are constantly being updated, and the purpose is to protect everyone’s driving safety.