Gas Sensor Application & Features

Gas sensors are a basic component in many security systems and modern methodology, providing key quality control feedback to the system. And these are available in wide specifications depending on the sensitivity levels, type of gas to be sensed, physical measurements and various different elements.

Gas sensors are generally battery operated. They transmit warnings via a series of audible and visible signals such as alarms and flashing lights, when hazardous levels of gas vapors are identified. As detectors measure a gas concentration, the sensor responds to a calibration gas, which serves as the reference point or scale.



The sensor module comprises of a steel exoskeleton under which a sensing component is housed. This sensing component is subjected to current through connecting leads. This current is known as heating current through it; the gases coming close to the sensing component get ionized and are absorbed by the sensing component. This changes the resistance of the sensing component which alters the value of the current going out of it.
FEATURES:
Stable performance, long life, low cost.
Simple drive circuit.
Fast response.
High sensitivity to combustible gas in wide range.
Stable performance, long life, low cost.

Gas detectors can be used to detect burnable, flammable and poisonous gases, and oxygen consumption. This type of device is used widely in industry and can be found in a variety of areas example on oil rigs, to screen produce forms and emerging technologies such as photovoltaic. They might additionally be utilized within firefighting.

The gas sensor is suitable for the detection of combustible gases, for example hydrogen, methane or propane / butane (LPG).



When combustible or reducing gases come in contact with the measuring element, they are subjected to catalytic combustion, which causes a rise in temperature. This rise causes a change in the resistance of the measuring element which is used as a measure of the component of gas being tested. The change in the sensor resistance is obtained as the change of the output voltage across the load resistor (RL) in series with the sensor resistance (RS). When combustible or reducing gases are absorbed by the surface of the sensor, the concentration of the test gas is determined by the change in conductivity. The constant 5V output of the data acquisition board is available for the heater of the sensor (VH) and for the detecting circuit (VC).
A typical working circuit

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