What Is an Alcohol/Breath Detector?
An alcohol/breath detector is a device used to measure the concentration of alcohol (ethanol) in the breath.
Alcohol in the body acts on the brain and causes paralysis of the senses, resulting in a significant loss of alertness and judgment.
By using an alcohol/breath detector, it is possible to prevent driving with insufficiently decomposed alcohol or to detect dangerous driving and prevent accidents from occurring.
Uses of Alcohol/Breath Detectors
Alcohol/breath detectors are used to prevent drunk driving and accidents caused by drunk driving.
In 2011, the regulations were amended to require that transportation operators be inspected at least once a week by an operation manager using alcohol/breath detectors to prevent accidents involving drivers.
In recent years, onboard alcohol/breath detectors have been developed, which, when alcohol is detected, stop the engine and make driving impossible.
Principles of Alcohol/Breath Detectors
There are two main types of alcohol/breath detectors: semiconductors and fuel cells.
The semiconductor method uses the change in electrical conductivity of a semiconductor, such as tin oxide heated to a high temperature for measurement.
When ordinary air comes into contact with the sensor, the oxygen in the air adheres to the sensor surface and binds the free electrons in the semiconductor, resulting in a low electrical conductivity.
It is inexpensive and compact, but somewhat less precise.
The fuel cell method, on the other hand, uses the generation of electricity by an electrode formed by a platinum catalyst and polymer membrane for measurement.
When ethanol is supplied to the detector electrode, it reacts with oxygen to produce hydrogen ions and electrons, which move across the electrode to generate electromotive force. Oxygen is also reduced at the counter electrode.
Since this reaction is unlikely to occur with components other than ethanol, ethanol can be detected with higher precision than with the semiconductor method. However, the disadvantage is the high running cost of the equipment.