What happens to the electrical voltage as more alcohol is present in the breath?

What happens to the electrical voltage as more alcohol is present in the breath?

• A. The voltage increases
• B. The voltage decreases
• C. Voltage stays the same
• D. Voltage fluctuates

Answer: (A)

In this breathalyzer setup, the sensor uses a fuel cell to detect alcohol. Alcohol in the breath is oxidized at the sensor, which drives a flow of electrons and creates an electrical current. The device translates that current into a voltage signal that is proportional to how much alcohol is present. So as there is more alcohol, the oxidation reaction occurs more vigorously, more current is produced, and the sensor’s output voltage rises. A rising voltage corresponds to a higher alcohol level, while less alcohol would produce a smaller voltage.

In this breathalyzer setup, the sensor uses a fuel cell to detect alcohol. Alcohol in the breath is oxidized at the sensor, which drives a flow of electrons and creates an electrical current. The device translates that current into a voltage signal that is proportional to how much alcohol is present. So as there is more alcohol, the oxidation reaction occurs more vigorously, more current is produced, and the sensor’s output voltage rises. A rising voltage corresponds to a higher alcohol level, while less alcohol would produce a smaller voltage.