Indian Journal of Science and Technology
Year: 2015, Volume: 8, Issue: 13, Pages: 1-7
Anindita Bora1* and Kanak Chandra Sarma2
1 Department of Electronics and Communication Engineering, Girijananda Chowdhury Institute of Management and Technology, Azara, Guwahati - 781017, Assam, India; [email protected]
2 Department of Instrumentation and USIC, Gauhati University, Guwahati - 781014, Assam, India; [email protected]
The procedure of temperature modulation of the metal oxide semiconductor gas sensor has been widely used for extracting characteristic response of a gas. This paper presents a Pulse Width Modulation (PWM) based temperature modulation circuit for semiconductor metal oxide gas sensor. A PIC microcontroller is programmed to generate different modulating 8 bit digital signal which is converted to analog signal using Digital to Analog Converter (DAC). The analog signal is then used to control a PWM based driver circuit which drives the heater of the metal oxide gas sensor. The kinetic response of a gas and metal oxide gas sensor materials are temperature dependent. The experimental results show that as the heating voltage of the gas sensor changes in different way, the sensor surface temperature also changes and the characteristic response of a particular gas sensor also varies in different way in presence of a gas. Hence the proposed system proves to be one of the efficient procedures to find out the best heating voltage waveform for a gas sensor to discriminate a particular gas easily. This way the selectivity of the gas sensor can also be improved.
Keywords: Gas Sensor, Metal Oxide Semiconductor, Temperature Modulation
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