How does a gas sensor work?

In order to identify, detect, measure, and confirm the presence of gases in an industrial setting, a gas sensor is needed. Based on the volume and concentration of a gas in an area, the sensor will produce what is called a “corresponding potential difference,” which changes the level of resistance of the material inside the sensor.

From this change in the level of resistance comes an electrical signal which is measured as output voltage. Your gas detector will gauge the output voltage of its sensor and provide you with a corresponding reading of the gas present.

A typical gas sensor is comprised of 6 components:

  • Gas sensing layer
  • Heater coil
  • Electrode Line
  • Electrode
  • Tubular Ceramic
  • Mesh over the sensing element
How gas sensors work: The typical layers of a gas sensor.

The gas sensing layer is the main piece of the sensor which is used to determine the concentration of gas in an environment and generate the electrical resistance change. Whenever a toxic gas is detected the resistance changes and the electrical current varies in flow, which indicates the difference in concentration of the gases.

The heater coil burns in the sensing element so that the efficiency and sensitivity of the sensing element increases. These coils have very high melting points that stay hot for long periods of time without melting.

The electrode is where the sensing layer output is connected to the electrode line, which is how the output current generated by the gas sensing layer can flow to the right terminal. The electrode is typically made of gold, or some other very good conductor.

The tubular ceramic layer is packed in between the heater coil and the gas sensing layer. It helps maintain the preheating of the sensing layer which will give high sensitivity to the sensing layer to get efficient output current.

The mesh over the sensing element protects the sensing elements and the setup–it mainly helps the sensor avoid and hold any dust particles that would enter the sensor and destroy the gas sensing layer.

If you have any questions about finding the right type of gas sensor for your needs and applications, please give us a call at 800-228-7612. Our customer support team will be happy to assist you.