Semiconductor breathalyzers

 

— sensor, which is based on a porous surface of a semiconductor material; when alcohol molecules enter the pores, the conductivity of the material changes, which is monitored by the device. This is the simplest and most inexpensive type of sensors, used mainly in models of the low-cost category. Actually, the main advantage of this option is precisely the low cost; also from the advantages of semiconductor devices can be called compactness. On the other hand, they are inferior to electrochemical ones in terms of speed, accuracy and selectivity of measurements — the sensor material reacts not only to alcohol, but also to some other compounds (in particular, ammonia and ketone bodies), moreover, the result strongly depends on the ambient temperature. Such a sensor needs to be checked and calibrated quite often — about once every 2 to 4 months, depending on the intensity of use; and its service life is relatively short.