LION SD-400 - Principle of Operation

lion alcolmeter
®
SD-400 User Handbook [v7]
2: Principle of Operation
The lion alcolmeter
®
SD-400 uses an electrochemical fuel cell
sensor to measure the concentration of alcohol vapour in the
subject’s expired breath; a measured amount of which is drawn from
the mouthpiece into the fuel cell by means of the sampling system.
In the fuel cell a voltage is generated in proportion to the breath
alcohol concentration: it is therefore amplified and displayed in
terms of the subject’s alcohol level.
The breath sampling system is factory-set to sample deep-lung air; it
is the breath from the bottom of the lungs that truly reflects the
amount of alcohol in the body.
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