Oxygen Sensors

Sensor generates electrical current proportional to the O2 concentration

Sensor used up over time (usually last one to three years)

Oxygen reduced to hydroxyl ions at cathode:

O₂ + 2H₂O + 4e^- 4OH^-

Hydroxyl ions oxidize lead (anode):

2Pb + 4OH^- 2PbO + 2H₂O + 4e^-

Overall cell reaction:

2Pb + O₂ 2PbO

• True percent by volume sensor
• Not influenced by changes in pressure due to:
  • Barometric pressure
  • Pressurized buildings
  • Altitude

Capillary pore (located under external moisture barrier filter)