Electrochemical

Principle

Electrochemical sensor consists of 2, 3 or 4 electrodes, which are located in a gel electrolyte. A system of electrodes and the electrolyte is separated from the atmosphere by a diffusion barrier. Gas molecules diffuse through this barrier and react with the electrolyte. There are oxidation and reduction reactions at the electrodes and they cause a change of cell potential. The higher the gas concentration is, the higher the potential will be.

Benefits

• Reliable and non-expensive sensors for „common“ gases

Weaknesses

• Long response time (up to few minutes for some gases)
• Higher price for special gases
• Potential failure when exposed with high concentrations
• Cross interferences (ozone sensor is sensitive to air flow, temperature and humidity changes)