Research Of Semiconductor Gas Sensor And Heating Temperature Modulation System

Combustible gas composition and content detection plays an important role in petrochemical ? steel smelting ? coal mining ? commerce and industry and other fields.Semiconductor gas sensors are often used for the detection of combustible gases,it has the advantages of fast response,high sensitivity and low cost.But in the real complex environment,the problem of poor selectivity of the sensor becomes the bottleneck of the development of the sensor.Therefore,how to effectively improve the selectivity of semiconductor gas sensor has been a hot research topic.In order to improve the selectivity of the gas sensor,the article prepares a Pt/SnO₂ semiconductor gas sensor,and the design of the sensor temperature modulation system with adjustable parameters,the system achieves the function of the modulation waveform output with different parameters and the sensor signal detection.Based on this platform,to explore the influence of temperature modulation method for selectivity of sensor.The hardware circuit of the sensor temperature modulation system based on STM32F107 processor,the system is composed of two parts which temperature modulation waveform output circuit and sensor signal detection circuit.The section of modulation waveform output can be the output sine wave and square wave,and their parameters such as the amplitude value and cycle could be adjustable.Signal detection part mainly includes signal conditioning circuit,signal limiting and filtering circuit,data acquisition and transmission circuit.At the same time,the hardware circuit driver is compiled and debugged by Keil4.0,which provides a reliable hardware platform for temperature modulation experiment.In addition,develop host computer software by Lab VIEW,realize the functions of the system communication,real-time display and storage of sensordata.This system takes two kinds of combustible gas of the CH4 and CO as the test object,test the output characteristics of different frequency parameters of the sensor based on the modulated waveform of sine wave and square wave.Take the amplitude ratio of the sensor temperature modulation for signal output,Analysis and processing experimental data,ensure the optimal modulation waveform and modulation parameters.The temperature modulation detection method can effectively improve the selectivity of semiconductor gas sensors by comparative analysis with static test results.It provides a new detection method in complex environment for combustible gas and other gases,and has broad application prospects.