MQ8 GAS SENSOR

A GAS sensor or a GAS Detector is defined as a chemical sensor that detects/measures the concentration of gas in its vicinity. A gas sensor is a simple drive circuit that interacts with gas to measure concentration. MQ8 sensor is ideal for the detection of Hydrogen concentration in the air such as portable gas detectors or in other industrial applications. Hydrogen is a colourless, odourless, tasteless, highly flammable nonmetallic gas. MQ8 sensor is a Tin oxide semiconductor sensor designed explicitly for Hydrogen (H2) concentration detection. It offers very good sensitivity and a fast response time, and also has anti-interference to other gases. MQ8 Gas sensor measures hydrogen concentrations ranging from 100 to 10, 000 ppm providing lower conductivity in clean air.

MQ8 works by detecting the hydrogen concentration of cycle high and low temperature and detecting H2 at low temperatures (heated by 1.5V). Analogue resistive output is provided by the sensor with conductivity higher along with the gas concentration rising. The resistance varies inside the sensor on the detection of hydrogen. Under the high temperature (heated by 5.0V), the other gases adsorbed under the low temperature are cleared.  We just need to power the heater coil with 5V, add a load resistance. As a result, the sensor and load resistor in the module form a potential divider and connect the output to an ADC or a simple OPAMP comparator.

Thus the hydrogen content is measured by measuring this resistance. Therefore the lower the sensor resistance, the upper the voltage reading is going to be. MQ8 sensor designed to operate at temperatures ranging from -10 to 50°C and consumes less than 150 mA current at 5 V.

Applications of MQ8 Gas Sensor:-

• Domestic gas leakage alarm
• Industrial flammable gas alarm
• Portable gas detector.