A breathalyzer or breathalyser is a device for estimating blood alcohol content (BAC) from a breath sample. Breathalyzer is the brand name (a genericized trademark) for the instrument that tests the alcohol level developed by inventor Robert Frank Borkenstein. It was registered as a trademark on May 13, 1954, but many people use the term to refer to any generic device for estimating blood alcohol content. When the user exhales into a breath analyzer, any ethanol present in their breath is oxidized to acetic acid at the anode. At the cathode, atmospheric oxygen is reduced. The overall reaction is the oxidation of ethenol to acetic acid and water. The electric current produced by this reaction is measured by a microcontroller, and displayed as an approximation of overall blood alcohol content (BAC) by the Alcosensor.
