Information Technology IT – 3 Monitoring and control | e-Consult

Gas sensors are devices designed to detect and measure the concentration of specific gases in the environment. Several technologies are employed for gas detection:

• Electrochemical Gas Sensors: These sensors rely on an electrochemical reaction between the target gas and an electrode. The reaction produces a current proportional to the gas concentration.
  Strengths: High sensitivity and selectivity for specific gases (e.g., CO, O2, H2S).
  Weaknesses: Limited lifespan, affected by temperature and humidity, require regular calibration.
  Application: Carbon monoxide detectors in homes and industrial safety systems.
• Semiconductor Gas Sensors (Metal Oxide Sensors): These sensors utilize a metal oxide semiconductor material whose electrical conductivity changes upon exposure to certain gases. The change in conductivity is measured as a change in resistance.
  Strengths: Relatively inexpensive, wide range of gases can be detected (e.g., CO, VOCs, methane).
  Weaknesses: Lower selectivity compared to electrochemical sensors, susceptible to humidity and temperature changes, can be affected by poisoning.
  Application: Air quality monitoring, detection of flammable gases in industrial environments.
• Infrared (NDIR) Gas Sensors: These sensors measure the absorption of infrared light by the target gas. The amount of light absorbed is directly proportional to the gas concentration.
  Strengths: High accuracy and stability, suitable for measuring a wide range of gases (e.g., CO2, methane, propane).
  Weaknesses: More expensive than other types, require a stable infrared source.
  Application: CO2 monitoring in HVAC systems, methane leak detection in natural gas pipelines.