阅读说明：本技术 基于等效电路的纳米气体传感器建模方法 (Nano gas sensor modeling method based on equivalent circuit ) 是由 苑振宇 李国成 张闯 焦天宇 平晋华 李臻 于 2021-01-19 设计创作，主要内容包括：本发明提供一种基于等效电路的纳米气体传感器建模方法,涉及气体传感器技术领域。该方法对纳米气体传感器进行盲盒处理及模块化处理,利用等效电路模拟纳米气体传感器,将整个纳米气体传感器等效电路封装后,产生与实际传感器相似的输入输出效果,而模块化处理则先通过功能进行初步划分,再对不同的参数、不同的运算过程和不同的表达形式进行模块细化,将等效电路划分为输入电路子系统、转化电路子系统和滤波电路子系统,三个子系统依次串联。本发明解决纳米气体传感器的模型建立过程中,仅能描述但不能模拟的问题,解决纳米气体传感器模型不具有普适性的问题以及同时描述不同参数变化对传感器响应影响的问题,从而降低成本,提高效率。(The invention provides a nano gas sensor modeling method based on an equivalent circuit, and relates to the technical field of gas sensors. The method carries out blind box processing and modularization processing on the nano gas sensor, utilizes an equivalent circuit to simulate the nano gas sensor, packages the equivalent circuit of the whole nano gas sensor to generate an input and output effect similar to that of an actual sensor, firstly carries out preliminary division through functions, then carries out module refinement on different parameters, different operation processes and different expression forms, divides the equivalent circuit into an input circuit subsystem, a conversion circuit subsystem and a filter circuit subsystem, and sequentially connects the three subsystems in series. The invention solves the problem that the model of the nano gas sensor can only be described but not simulated in the process of establishing the model, and solves the problems that the model of the nano gas sensor has no universality and the influence of different parameter changes on the response of the sensor is described at the same time, thereby reducing the cost and improving the efficiency.)

1. A nanometer gas sensor modeling method based on an equivalent circuit is characterized in that: the method carries out blind box processing and modularization processing on the nano gas sensor, utilizes an equivalent circuit to simulate the nano gas sensor, packages the equivalent circuit of the whole nano gas sensor to generate an input and output effect similar to that of an actual sensor, firstly carries out preliminary division through functions, then carries out module refinement on different parameters, different operation processes and different expression forms, divides the equivalent circuit into an input circuit subsystem, a conversion circuit subsystem and a filter circuit subsystem, and sequentially connects the three subsystems in series;

the input circuit subsystem is used for simulating the adsorption and diffusion of gas on the gas-sensitive material of the nano gas sensor, namely, the gas input process in the actual test process is simulated by inputting an electric signal, and the generated gas concentration equivalent electric signal enters the conversion circuit subsystem through the input port of the conversion circuit subsystem after being output by the output end of the input circuit subsystem;

the conversion circuit subsystem is used for converting gas concentration equivalent electric signals transmitted by the input circuit subsystem into sensor response equivalents and outputting the sensor response equivalents to the filter circuit, under the condition that Fick's law is suitable for surface reaction of the porous gas sensing material, and experimental gas follows Frandlier's law in the gas adsorption process, gas concentration signals output from the input circuit subsystem are converted into adjustable electric signals by utilizing the multistage operation circuit according to a diffusion reaction equation of gas and a relation between the conductance of the gas sensitive film and the gas concentration, the parameters which can affect the gas sensitive characteristics are calculated according to the equation, the sensing characteristics of the whole nano gas sensor are simulated, and results generated by multistage operation are output to the filter circuit subsystem; wherein, the diffusion reaction equation of the gas is as follows:

wherein C is the volume concentration of the diffusion gas; t is diffusion time; x is the diffusion distance; d is a diffusion coefficient, is theoretically a second-order tensor containing 9 components and is closely related to the structural symmetry of a diffusion system; the value of gamma is 1 under the condition of small-range coverage;

when gas is injected in a closed container, the equation becomes:

wherein Γ res is response time, Γ b is recovery time, and ι is film thickness; c₀To start the diffusion, the concentration of the gas to be measured in the air, D_eIs the diffusion coefficient of the gas-sensitive material of the sensor;

the filter circuit subsystem has adjustable bandwidth and cut-off frequency, calculates corresponding frequency according to the estimated response-recovery time, sets the bandwidth and the cut-off frequency according to the frequency, filters out complex noise generated in the operation process, leaves a response waveform which is suitable for subsequent processing and is close to the actual sensor response, and outputs the response waveform to the oscilloscope from an output port of the filter circuit subsystem.

2. The equivalent circuit-based nano-gas sensor modeling method of claim 1, wherein: in the input circuit subsystem, the concentration of the gas to be detected diffused in the gas sensitive material is equivalent to a main independent variable which causes the next circuit simulation response in a circuit structure; an alternating current voltage source is equivalent to a variable gas concentration signal, the amplitude voltage of the alternating current voltage source represents the maximum value of the gas concentration, the frequency of the voltage change of the alternating current voltage source represents the speed of the gas concentration change, and the alternating current voltage source is connected into an operational amplification circuit for processing, so that the gas concentration signal change output from an input circuit subsystem is consistent with the form of the actual gas concentration change;

in the course of carrying on the rough test, utilize the controlled adjustable signal source to replace the input circuit directly; when a specific sensor is simulated, designing according to whether the concentration change process in the actual diffusion of the gas has an equivalent elementary function model or not; if the equivalent elementary function model exists, directly utilizing a signal source generating the elementary function type signal to simulate the generation of the signal; if the gas sensor has a unique response rule, the operational amplifier processing is carried out on a certain basic function signal according to the response rule of the gas sensor, and the effect approximately equivalent to the diffusion process generated on the gas sensitive material of the original gas sensor is achieved.

3. The equivalent circuit-based nano-gas sensor modeling method of claim 2, wherein: in the conversion circuit subsystem, parameters which are irrelevant to each other except the diffusion concentration transmitted by the input circuit subsystem are respectively generated by circuit elements or circuit modules which are not influenced with each other, and the structures are respectively designed according to the response change of the conversion circuit subsystem; in the actual sensing process, the part of parameters which are kept unchanged and have no change on the influence of signals are equivalent by using a capacitor, a resistor and a signal source; parameters which have more complex influence on the sensing process are given by an equivalent circuit branch network; the coupling between circuit elements or circuit modules corresponding to different parameters is realized by an arithmetic circuit according to a gas diffusion reaction equation, the common influence of a plurality of variables which are in direct proportion or inverse proportion to a response result under the same condition is converted into the same signal by a four-quadrant multiplication circuit, then the influence of different variables is mutually accumulated by addition operation, finally, the influence of time accumulation on the response result is obtained by an integrating circuit, and the result generated by multi-stage operation is output to a filter circuit subsystem.

4. The equivalent circuit-based nano-gas sensor modeling method of claim 3, wherein: the macroscopic change of the nano gas sensor caused by a certain characteristic is actually caused by a plurality of microscopic changes, the influence of each microscopic change caused by the change of the certain characteristic in the sensor on an output signal is equivalent to a branch of the branch network, the branches are mutually coupled to form the branch network, and after the branch network processes a gas concentration signal transmitted by the input circuit subsystem together, a result similar to the response of the certain characteristic of the actual sensor is output; a time delay device is added into a single branch circuit to simulate the speed of different microscopic changes; a voltage-controlled resistor is added into each branch, the intensity of different micro processes is simulated through different piezoresistive proportions, and voltage signals are converted into resistance signals.

Technical Field

The invention relates to the technical field of gas sensors, in particular to a nano gas sensor modeling method based on an equivalent circuit.

Background

The gas sensor is a device that can convert information such as the composition and concentration of a gas into an electric signal, and there are various types such as a semiconductor gas sensor, an electrochemical gas sensor, a catalytic combustion gas sensor, a thermal conductivity gas sensor, an infrared gas sensor, and a solid electrolyte gas sensor.

In recent years, gas sensors have been widely developed in biological, chemical, mechanical, aviation, military and other fields, and nanostructured materials have been widely used for manufacturing gas sensors due to advantages of being capable of reducing working temperature, consuming less energy and the like, and when the materials reach a nanoscale, the properties of the materials are often mutated. The nanostructure material is mainly characterized by a particularly high specific surface area, which will facilitate sufficient contact between the detection layer of the sensor and the gas to be detected, thereby enhancing the sensitivity of the sensor.

In the aspect of model calculation, physical mathematical models aiming at the semiconductor metal oxide sensor are not unified all the time, and the related theories are numerous. On one hand, the internal mass transfer sensitive mechanism of the sensor for guiding modeling is not clear, and on the other hand, the gas sensor has a plurality of materials and a plurality of gases to be measured, so that a modeling method with universality is difficult to find by a physical modeling method.

At present, the model establishment of the nano gas sensor is mostly based on the description of the response process of the gas sensitive material at different angles through a formula, but not by establishing an equivalent model for simulation. Therefore, as the research goes deeper, we can obtain a more definite response mechanism of the nano-gas sensor, but a simpler representation form cannot be obtained, and the design and production of the actual nano-gas sensor are not highly facilitated. In fact, in the design process of the nano gas sensor, new sensors need to be continuously manufactured and tested to determine the response condition of the nano gas sensor, and in the testing process, if only one sample is measured under one condition at a time, not only a lot of time is spent, but also the process becomes very complicated. Meanwhile, a common measurement method can only correspond to one specific condition at a time, and if the response capability is required to change along with various variables, the subsequent experimental data processing is time-consuming. Therefore, a universal modeling platform is needed to design the sensor without a large amount of sensors.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a nano gas sensor modeling method based on an equivalent circuit aiming at the defects of the prior art, wherein an electric signal is used for replacing an environmental variable and parameters inside a sensor, and the equivalent circuit is used for realizing the response of the approximately replaced sensor in an actual test circuit, so that the cost is reduced and the efficiency is improved.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a nanometer gas sensor modeling method based on equivalent circuit, the method carries on blind box processing and modularization processing to the nanometer gas sensor, utilize equivalent circuit to imitate the nanometer gas sensor, encapsulate the equivalent circuit of the whole nanometer gas sensor, produce the similar input/output effect with the actual sensor, and the modularization processing is divided primarily through the function first, and then carry on the module refinement to different parameters, different operation process and different expression forms, divide the equivalent circuit into input circuit subsystem, conversion circuit subsystem and filter circuit subsystem, three subsystems connect in series sequentially;

the input circuit subsystem is used for simulating the adsorption and diffusion of gas on the gas-sensitive material of the nano gas sensor, namely, the gas input process in the actual test process is simulated by inputting an electric signal, and the generated gas concentration equivalent electric signal enters the conversion circuit subsystem through the input port of the conversion circuit subsystem after being output by the output end of the input circuit subsystem;

the conversion circuit subsystem is used for converting gas concentration equivalent electric signals transmitted by the input circuit subsystem into sensor response equivalents and outputting the sensor response equivalents to the filter circuit, under the condition that Fick's law is suitable for surface reaction of the porous gas sensing material, and experimental gas follows Frandlier's law in the gas adsorption process, gas concentration signals output from the input circuit subsystem are converted into adjustable electric signals by utilizing the multistage operation circuit according to a diffusion reaction equation of gas and a relation between the conductance of the gas sensitive film and the gas concentration, the parameters which can affect the gas sensitive characteristics are calculated according to the equation, the sensing characteristics of the whole nano gas sensor are simulated, and results generated by multistage operation are output to the filter circuit subsystem; wherein, the diffusion reaction equation of the gas is as follows:

wherein C is the volume concentration of the diffusion gas; t is diffusion time; x is the diffusion distance; d is a diffusion coefficient, is theoretically a second-order tensor containing 9 components and is closely related to the structural symmetry of a diffusion system; the value of gamma is 1 under the condition of small-range coverage;

when gas is injected in a closed container, the equation becomes:

wherein Γ res is response time, Γ b is recovery time, and ι is film thickness; c₀To start the diffusion, the concentration of the gas to be measured in the air, D_eIs the diffusion coefficient of the gas-sensitive material of the sensor;

the filter circuit subsystem has adjustable bandwidth and cut-off frequency, calculates corresponding frequency according to the estimated response-recovery time, sets the bandwidth and the cut-off frequency according to the frequency, filters out complex noise generated in the operation process, leaves a response waveform which is suitable for subsequent processing and is close to the actual sensor response, and outputs the response waveform to the oscilloscope from an output port of the filter circuit subsystem.

Further, inputting the concentration of the gas to be measured diffused in the gas sensitive material into a circuit subsystem, wherein the concentration of the gas to be measured is equivalent to a main independent variable which causes the next circuit simulation response to be generated; an alternating current voltage source is equivalent to a variable gas concentration signal, the amplitude voltage of the alternating current voltage source represents the maximum value of the gas concentration, the frequency of the voltage change of the alternating current voltage source represents the speed of the gas concentration change, and the alternating current voltage source is connected into an operational amplification circuit for processing, so that the gas concentration signal change output from an input circuit subsystem is consistent with the form of the actual gas concentration change;

in the course of carrying on the rough test, utilize the controlled adjustable signal source to replace the input circuit directly; when a specific sensor is simulated, designing according to whether the concentration change process in the actual diffusion of the gas has an equivalent elementary function model or not; if the equivalent elementary function model exists, directly utilizing a signal source generating the elementary function type signal to simulate the generation of the signal; if the gas sensor has a unique response rule, the operational amplifier processing is carried out on a certain basic function signal according to the response rule of the gas sensor, and the effect approximately equivalent to the diffusion process generated on the gas sensitive material of the original gas sensor is achieved.

Furthermore, in the conversion circuit subsystem, parameters which are irrelevant to each other except the diffusion concentration transmitted by the input circuit subsystem are respectively generated by circuit elements or circuit modules which are not influenced mutually, and the structures are respectively designed according to the response change of the conversion circuit subsystem; in the actual sensing process, the part of parameters which are kept unchanged and have no change on the influence of signals are equivalent by using a capacitor, a resistor and a signal source; parameters which have more complex influence on the sensing process are given by an equivalent circuit branch network; the coupling between circuit elements or circuit modules corresponding to different parameters is realized by an arithmetic circuit according to a gas diffusion reaction equation, the common influence of a plurality of variables which are in direct proportion or inverse proportion to a response result under the same condition is converted into the same signal by a four-quadrant multiplication circuit, then the influence of different variables is mutually accumulated by addition operation, finally, the influence of time accumulation on the response result is obtained by an integrating circuit, and the result generated by multi-stage operation is output to a filter circuit subsystem.

Furthermore, the macroscopic change of the nano gas sensor caused by a certain characteristic is actually caused by a plurality of microscopic changes, the influence of each microscopic change caused by the certain characteristic change in the sensor on the output signal is equivalent to a branch of the branch network, the branches are mutually coupled to form the branch network, and after the branch network processes the gas concentration signal transmitted by the input circuit subsystem together, the result similar to the response of the certain characteristic of the actual sensor is output; a time delay device is added into a single branch circuit to simulate the speed of different microscopic changes; a voltage-controlled resistor is added into each branch, the intensity of different micro processes is simulated through different piezoresistive proportions, and voltage signals are converted into resistance signals.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the equivalent circuit-based nano gas sensor modeling method provided by the invention can simulate a nano gas sensor by utilizing the equivalent circuit, can replace environmental variables and parameters inside the sensor by electric signals, can realize the response of an approximate substitute sensor in an actual test circuit by utilizing the equivalent circuit only by obtaining key parameters of the sensor and environmental parameters with larger influence, solves the problem that the nano gas sensor model can only be described but cannot be simulated in the model establishing process, solves the problem that the nano gas sensor model has no universality and simultaneously describes the influence of different parameter changes on the sensor response, thereby reducing the cost and improving the efficiency.

Drawings

FIG. 1 is a schematic structural diagram of a nano-gas sensor; wherein, (a) is a front view, (b) is a left view, and (c) is a top view;

fig. 2 is a schematic diagram of an overall structure of an equivalent circuit according to an embodiment of the present invention;

FIG. 3 is a circuit diagram of an input circuit subsystem according to an embodiment of the present invention;

FIG. 4 is a circuit diagram of a converter circuit subsystem according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an equivalent circuit of a single effect of temperature on a sensing process according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an equivalent circuit network in which temperature affects a sensing process according to an embodiment of the present invention;

fig. 7 is a circuit diagram of a filter circuit subsystem according to an embodiment of the present invention.

In the figure: 1. a base; 2. a sensor lower pin; 3. a ceramic tube; 4. a resistance wire; 5. a sensor upper pin; 6. and (7) leading wires.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

This example performs a model simulation of the nano-gas sensor shown in fig. 1. In the nano gas sensor, gas-sensitive materials are diluted and then evenly coated on the surface of a ceramic tube, a resistance wire is placed inside the ceramic tube, and finally two ends of the resistance wire and four pins of the ceramic tube are welded with a base. The voltage at the two ends of the resistance wire is changed, so that the power of the resistance wire is changed, the temperature is changed, and the response capability of the material to gas is reflected from the change condition of the output current.

The response performance of nano-gas sensors is affected by a number of factors. Under the condition that other conditions are not changed, sensors of different gas sensitive materials have different response capacities even under the same gas environment, and the same sensor has different response capacities for gas to be measured with different concentrations. In addition, changes in temperature can also affect the responsiveness of the sensor.

Therefore, in the design process of the sensor model, the gas sensitive material parameters, the gas parameters to be detected, the concentration of the gas to be detected and the working temperature of the sensor need to be respectively subjected to signal conversion, so that a result similar to the actual response of the sensor is obtained. In order to make the designed equivalent model universal, it is necessary to make each parameter influencing the sensor response adjustable to simulate the response process of different materials, different gases to be measured and different environments. In the method for simulating the nano gas sensor by the equivalent circuit in the embodiment, the electric signal is selected as the equivalent signal of each parameter and variable in the response process of the sensor, and the actual response of the sensor can be simulated under the condition that the form and the size of the electric signal are changed by changing the circuit structure and the element parameters so as to freely represent the change of each parameter.

The embodiment carries out blind box processing and modular processing on the nano gas sensor, namely, after the equivalent circuit of the whole nano gas sensor is encapsulated, the input and output effect similar to that of an actual sensor is generated, the modular processing is firstly subjected to preliminary division through functions, and then the modules are refined for different parameters, different operation processes and different expression forms, so that the simulation process can reasonably depend on the simulation process.

The embodiment specifically provides a nano gas sensor modeling method based on an equivalent circuit, wherein in the design process, the equivalent circuit is used for simulating a nano gas sensor, the equivalent circuit of the nano gas sensor is divided into three subsystems of an input circuit, a conversion circuit and a filter circuit, the three subsystems are sequentially connected in series, a gas concentration equivalent electric signal generated from the input circuit subsystem enters the conversion circuit subsystem through an input port of the conversion circuit after being output from an output end of the input circuit subsystem, is output from an output port of the conversion circuit after being processed by the conversion circuit and enters an input port of the filter circuit, and is output to an oscilloscope from an output port of the filter circuit after being subjected to waveform modification by the filter circuit. The overall coupling manner between subsystems is shown in fig. 2, and the functions and design methods of the subsystems are as follows.

Fig. 3 is a schematic diagram of a circuit structure of a subsystem of an input circuit, where the input circuit is used to simulate the adsorption and diffusion of gas on a gas-sensitive material of a nano gas sensor, and equate the concentration of a gas to be measured diffused in the gas-sensitive material in the circuit structure as a main independent variable causing the next circuit simulation response. An alternating current voltage source is equivalent to a variable gas concentration signal, the amplitude voltage of the voltage represents the maximum value of the gas concentration, the frequency of the voltage change represents the speed of the gas concentration change, and the alternating current voltage source is connected to an operational amplification circuit for processing, so that the gas concentration signal change output from an input circuit subsystem is consistent with the form of the actual gas concentration change. In the course of carrying on the rough test, can utilize the controlled adjustable signal source to replace the input circuit directly, while simulating the concrete sensor, whether there is equivalent elementary function model to design according to the concentration change process in the actual diffusion of the gas, if there is equivalent elementary function model then can utilize the signal source producing the function type signal to simulate the production of the signal directly, if there is unique response law, carry on the operational amplifier processing to a certain basic function signal according to its own response law, reach the effect similar to diffusion process that takes place on the gas-sensitive material of the original gas sensor, in fig. 3, insert the alternating current voltage source into the second grade operational amplifier circuit in order to express this process. The concentration change signal generated by the input circuit enters the conversion circuit after being output from the output port of the input circuit subsystem.

Fig. 4 is a schematic diagram of a circuit structure of a subsystem of a conversion circuit, wherein the conversion circuit is used for calculating a gas concentration signal input from an input circuit by using a multi-stage operation circuit according to a diffusion reaction equation of gas and a relational expression of conductance and gas concentration of a gas-sensitive film, and obtaining an output signal similar to the response of an actual sensor. The diffusion reaction equation for gases is:

where C is the volume concentration of the diffusion gas, t is the diffusion time, and x is the diffusion distance. The diffusion coefficient D is theoretically a second-order tensor containing 9 components, and is closely related to the structural symmetry of the diffusion system. Gamma is taken to be 1 in the case of small-range coverage.

When gas is injected in a closed container, the equation becomes:

wherein Γ res is response time, Γ b is recovery time, and ι is film thickness; c₀To openConcentration of gas to be measured in air at initial diffusion, D_eIs the diffusion coefficient of the gas-sensitive material of the sensor.

The independent variables except the diffusion concentration are respectively generated by circuit elements or circuit modules which are not influenced mutually, the structures are respectively designed according to the corresponding change of the independent variables, most parameters are kept unchanged in the actual sensing process, and the influence of the parameters on signals is not changed, so that the equivalent effects can be realized by using capacitors, resistors and signal sources.

Meanwhile, among various parameters influencing the response of the sensor, the working temperature of the sensor is special, the influence on the sensing process is complex, and the macroscopic change of the nano gas sensor caused by the temperature characteristic is actually caused by a plurality of microscopic changes, including the processes of oxygen ion adsorption, electron adsorption, transition and oxidation heat release, so that the influence of the temperature characteristic on the response process of the nano gas sensor is simulated by utilizing the equivalent circuit branch network. The present embodiment uses an ac voltage source to represent temperature variation, the voltage amplitude represents temperature level, and the frequency represents temperature change speed. In the microscopic process, the motion degrees of electrons in different temperature ranges, namely the sensitivity of the sensor, are different, so that a delay device L1 is added into a single branch circuit to simulate the speed of different microscopic changes. The severity of different microscopic responses is different, so that a voltage-controlled resistor U1 is added in the circuit, the severity of different microscopic processes is simulated through different piezoresistive proportions, and a voltage signal is converted into a resistance signal. The influence of each microscopic change caused by the temperature change in the sensor on the output signal is equivalent to a branch of the circuit, as shown in fig. 5, and the branches are coupled with each other to form a branch network shown in fig. 6, and the branch network processes the temperature signal together and outputs a result similar to the temperature response of the actual sensor. In the whole analog circuit, two output ends of the branch network, namely two ports connected with the oscilloscope, are respectively connected with the positive end and the negative end of the IO2 in fig. 4, so that the temperature signal is introduced into the operation of the whole analog circuit.

The diffusion reaction equation of coupling reference gas between different parameter analog circuits is realized by using an arithmetic circuit, the common influence of a plurality of variables which are in direct proportion or inverse proportion to a response result under the same condition on the circuit is converted into the same signal by using a four-quadrant multiplication circuit, the influence of different variables is mutually accumulated by using addition operation, finally, the influence of time accumulation on the response result is obtained by using an integration circuit, and the result generated by multi-stage operation is output to a filter circuit.

FIG. 7 is a schematic diagram of a subsystem of a filter circuit for filtering the electrical signal from the conversion circuit to leave a smoother signal waveform for analysis. The designed filter circuit has adjustable bandwidth and cut-off frequency, is a structure of a band-pass filter, calculates corresponding frequency according to estimated response-recovery time in the design process of a specific equivalent circuit, sets the bandwidth and the cut-off frequency according to the frequency, filters out complex noise generated in the operation process, and leaves an output waveform which is suitable for subsequent processing and is close to the response of an actual sensor. The processed signal output from the filter circuit can be connected to an oscilloscope like a normal gas sensor, and the response result is observed.

The specific simulation process of the equivalent circuit example of the nano gas sensor designed by the embodiment is as follows: the input circuit uses the group alternating voltage source signal to obtain an equivalent circuit signal approximately replacing the change of the gas concentration through the secondary operational amplifier processing; in the conversion circuit, combining with a formula, simulating the process of gas-sensitive film adsorption of the nano gas sensor and responding to the change of the concentration of the gas to be detected by utilizing the coupling of the coupling circuit of the arithmetic circuit, wherein except that the concentration signal of the gas to be detected is provided by the input circuit, each parameter which does not influence each other is respectively provided by different circuit elements or circuit modules; the signal output by the conversion circuit is processed by the filter circuit, and the obtained circuit signal is transmitted to the oscilloscope for observation.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions and scope of the present invention as defined in the appended claims.