A dual-range gas detection device and a gas detector

Abstract

The invention belongs to the field of gas detection, and discloses a dual-range gas detection device and a gas detector. A gas sensor is used to detect gas concentration to generate a gas sampling signal; a first amplifying circuit amplifies the gas sampling signal to generate a first amplified signal; a second amplifying circuit amplifies the first amplified signal to generate a second amplified signal; a control circuit generates a display signal according to the first amplified signal and the second amplified signal; a display component displays according to the display signal; since the gas sampling signal is amplified in two stages, and the amplified signals after the first amplification and the second amplification are respectively input into the control circuit, the control circuit generates a display signal according to the first amplified signal after the first amplification or the second amplified signal after the second amplification according to the comparison result of the voltage value of the second amplified signal after the second amplification and a preset threshold value, thereby realizing dual-range detection in the case of configuring a gas sensor.

Description

Technical Field

[0001] The invention belongs to the field of gas detection, and in particular relates to a dual-range gas detection device and a gas detector. Background Art

[0002] The conventional dual-range gas detection device includes a gas detection unit, a signal amplification unit, a control unit, an alarm unit, a display unit and a power supply unit. The gas detection unit includes a first gas sensor and a second gas sensor. The range of the first gas sensor is 0-10% vol, which is used to output a first detection signal. The range of the second gas sensor is 10-100% vol. The signal amplification unit includes a first amplification circuit and a second amplification circuit. The first amplification circuit includes a first in-phase amplification circuit and a first differential amplification circuit, and the second amplification circuit includes a second in-phase amplification circuit and a second differential amplification circuit. However, due to the configuration of two gas sensors and the high price of the gas sensors, the circuit is complex and the hardware cost is high. Summary of the invention

[0003] The present invention provides a dual-range gas detection device and an electric energy meter, aiming to solve the problem that a traditional dual-range gas detection device is equipped with two gas sensors and the gas sensors are relatively expensive, thus resulting in complex circuits and high hardware costs.

[0004] The present invention is implemented as follows: a dual-range gas detection device, comprising:

[0005] a gas sensor configured to detect a gas concentration to generate a gas sampling signal;

[0006] A first amplifying circuit connected to the gas sensor and configured to amplify the gas sampling signal to generate a first amplified signal;

[0007] a second amplifying circuit connected to the first amplifying circuit and configured to amplify the first amplified signal to generate a second amplified signal;

[0008] A control circuit connected to the first amplifying circuit and the second amplifying circuit, and configured to generate a display signal according to the first amplified signal and the second amplified signal respectively;

[0009] A display component connected to the control circuit and configured to display according to a display signal.

[0010] In one embodiment, the dual-range gas detection device further includes:

[0011] a first follower connected between the first amplifying circuit and the control circuit; and

[0012] A first follower is connected between the second amplifying circuit and the control circuit.

[0013] In one embodiment, the dual-range gas detection device further includes:

[0014] The control circuit is connected to the control circuit and is configured as a wired communication circuit for bidirectional interaction with a host computer.

[0015] In one embodiment, the dual-range gas detection device further includes:

[0016] An alarm component is connected to the control circuit and configured to alarm the gas concentration.

[0017] In one embodiment, the control circuit is specifically configured to generate the display signal according to the first amplified signal when the voltage value of the second amplified signal is greater than a preset threshold, and to generate the display signal according to the second amplified signal when the voltage value of the second amplified signal is less than or equal to the preset threshold.

[0018] In one embodiment, the control circuit includes a microprocessor;

[0019] The power supply terminal of the microprocessor is connected to the first power supply, the first analog input terminal of the microprocessor is the first amplified signal input terminal of the control circuit, the second analog input terminal of the microprocessor is the second amplified signal input terminal of the control circuit, and the ground terminal of the microprocessor is connected to the power ground.

[0020] In one embodiment, the second amplifying circuit includes a first operational amplifier, a first resistor, a second resistor and a third resistor;

[0021] The first end of the first resistor is the first amplified signal input end of the second amplifier circuit, the first end of the second resistor is the reference voltage input end of the second amplifier circuit, the second end of the first resistor is connected to the inverting input end of the first operational amplifier and the first end of the third resistor, the second end of the second resistor is connected to the non-inverting input end of the first operational amplifier, the output end of the first operational amplifier and the second end of the third resistor together constitute the second amplified signal output end of the second amplifier circuit, the power supply end of the first operational amplifier is connected to the second power supply VBB, and the ground end of the first operational amplifier is connected to the power ground.

[0022] In one embodiment, the first amplifying circuit comprises:

[0023] An adjustable resistance component providing a reference voltage;

[0024] A first amplifying component connected to the adjustable resistance component and configured to amplify the reference voltage to generate the third amplified signal, and amplify the gas sampling signal to generate a fourth amplified signal;

[0025] a second amplifying component generating a reference voltage;

[0026] A differential amplifier component is connected to the first amplifier component and the second amplifier component and is configured to generate the first amplified signal according to the reference voltage, the third amplified signal and the fourth amplified signal.

[0027] In one embodiment, the adjustable resistor component includes an adjustable resistor, a fourth resistor and a fifth resistor;

[0028] The first end of the fourth resistor is connected to the third power supply, the second end of the fourth resistor is connected to the first end of the adjustable resistor, the adjustment end of the adjustable resistor is the reference voltage output end of the adjustable resistor component, the second end of the adjustable resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is connected to the power ground.

[0029] In one embodiment, the first amplifying component includes a second operational amplifier, a third operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor;

[0030] The non-inverting input terminal of the second operational amplifier is connected to the first end of the sixth resistor and the first end of the seventh resistor, the second end of the sixth resistor is the gas sampling signal input terminal of the first amplifier component, the inverting input terminal of the second operational amplifier is connected to the first end of the eighth resistor and the first end of the ninth resistor, the output terminal of the second operational amplifier and the second end of the eighth resistor jointly constitute the fourth amplified signal output terminal of the first amplifier component, the second end of the ninth resistor is connected to the first end of the tenth resistor and the inverting input terminal of the third operational amplifier, the second end of the tenth resistor and the output terminal of the third operational amplifier jointly constitute the third amplified signal output terminal of the first amplifier component, the first end of the eleventh resistor is connected to the non-inverting input terminal of the third operational amplifier, the second end of the eleventh resistor is the reference voltage input terminal of the first amplifier component, and the second end of the seventh resistor is connected to the power ground.

[0031] In one embodiment, the second amplifying component includes a fourth operational amplifier, a first capacitor, a twelfth resistor and a thirteenth resistor;

[0032] The non-inverting input terminal of the fourth operational amplifier is connected to the first end of the twelfth resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is connected to a fourth power supply, the inverting input terminal of the fourth operational amplifier and the output terminal of the fourth operational amplifier together constitute the reference voltage output terminal of the second amplifying component, the power supply terminal of the fourth operational amplifier and the first end of the first capacitor are commonly connected to the third power supply, and the ground terminal of the fourth operational amplifier and the second end of the thirteenth resistor are commonly connected to the power ground.

[0033] In one embodiment, the differential amplifier component includes a fifth operational amplifier, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor;

[0034] The first end of the fourteenth resistor is the third amplified signal input terminal of the differential amplifier component, the inverting input terminal of the fifth operational amplifier is connected to the second end of the fourteenth resistor and the first end of the seventeenth resistor, the first end of the fifteenth resistor is the fourth amplified signal input terminal of the differential amplifier component, the first end of the sixteenth resistor is the reference voltage input terminal of the differential amplifier component, the second end of the fifteenth resistor is connected to the second end of the sixteenth resistor and the non-inverting input terminal of the fifth operational amplifier, and the output terminal of the fifth operational amplifier and the second end of the seventeenth resistor together constitute the first amplified signal output terminal of the differential amplifier component.

[0035] An embodiment of the present invention further provides a gas detector, which includes the dual-range gas detection device as described above.

[0036] In the embodiment of the present invention, since the gas sampling signal is amplified in two stages, and the amplified signals after the first stage amplification and the second stage amplification are respectively input into the control circuit, when the voltage value of the second amplified signal after the second stage amplification is greater than the preset threshold value, the control circuit generates a display signal according to the first amplified signal corresponding to the first stage range after the first stage amplification; when the voltage value of the second amplified signal after the second stage amplification is less than or equal to the preset threshold value, the control circuit generates a display signal according to the second amplified signal corresponding to the second stage range after the second stage amplification, thereby realizing dual-range detection when one gas sensor is configured. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical invention in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1A module structure diagram of a dual-range gas detection device provided by an embodiment of the present invention;

[0039] Figure 2 Another module structure diagram of the dual-range gas detection device provided by an embodiment of the present invention;

[0040] Figure 3 Another module structure diagram of the dual-range gas detection device provided by an embodiment of the present invention;

[0041] Figure 4 Another module structure diagram of the dual-range gas detection device provided by an embodiment of the present invention;

[0042] Figure 5 A module structure diagram of a first amplifier circuit of a dual-range gas detection device provided in an embodiment of the present invention;

[0043] Figure 6 This is an example circuit structure diagram of a dual-range gas detection device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] Figure 1 The module structure of the dual-range gas detection device provided by the embodiment of the present invention is shown. For the convenience of description, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0046] The dual-range gas detection device comprises a gas sensor 11 , a first amplifying circuit 12 , a second amplifying circuit 13 , a control circuit 14 and a display component 15 .

[0047] The gas sensor 11 detects the gas concentration to generate a gas sampling signal; the first amplifier circuit 12 is connected to the gas sensor 11, and is configured to amplify the gas sampling signal to generate a first amplified signal; the second amplifier circuit 13 is connected to the first amplifier circuit 12, and is configured to amplify the first amplified signal to generate a second amplified signal; the control circuit 14 is connected to the first amplifier circuit 12 and the second amplifier circuit 13, and is configured to generate display signals according to the first amplified signal and the second amplified signal respectively; the display component 15 is connected to the control circuit 14, and is configured to display according to the display signal.

[0048] Therefore, the gas leakage detection is solved by the above-mentioned dual-range gas detection device, and the sensor gas sampling signal is amplified and processed. Through two-way operational amplification, the gas sampling signal is amplified to the parts per million (ppm) level to generate a second amplified signal, and the gas sampling signal is amplified to the lower explosion limit (Lower Explosion Limited, % LEL) level to generate a first amplified signal. The two-channel analog-to-digital converter of the control circuit can be used to detect the amplified signals of the two ranges respectively, and the control circuit can realize range switching and display the measured value.

[0049] Specifically, the control circuit 14 is specifically configured to generate a display signal according to the first amplified signal when the voltage value of the second amplified signal is greater than a preset threshold, and to generate a display signal according to the second amplified signal when the voltage value of the second amplified signal is less than or equal to the preset threshold.

[0050] When the voltage value of the second amplified signal is greater than the preset threshold, it means that the gas sampling signal has exceeded the ppm level range. At this time, a display signal is generated according to the first amplified signal of the %LEL level; when the voltage value of the second amplified signal is greater than the preset threshold, it means that the gas sampling signal has not exceeded the ppm level range. At this time, a display signal is generated according to the second amplified signal of the ppm level; therefore, the switching of dual-range gas detection is accurately realized.

[0051] like Figure 2 As shown, the dual-range gas detection device further includes a first follower 16 and a second follower 17 .

[0052] The first follower 16 is connected to the first amplifier circuit 12 and the control component, and is configured to follow and output the first amplified signal; the second follower 17 is connected to the second amplifier circuit 13 and the control component, and is configured to follow and output the second amplified signal.

[0053] The first follower 16 follows and outputs the first amplified signal, and the second follower 17 follows and outputs the second amplified signal, thereby reducing the output impedance of the amplifier circuit, so that the output impedance of the amplifier circuit matches the input impedance of the control circuit, and improving the accuracy of gas detection.

[0054] like Figure 3 As shown, the dual-range gas detection device further includes a wired communication circuit 18 .

[0055] The wired communication circuit 18 is connected to the control circuit 14 and is configured to perform bidirectional interaction with the host computer.

[0056] Specifically, the wired communication circuit 18 generates a second wired communication signal according to the first wired communication signal to perform bidirectional interaction with the host computer; the control circuit 14 is also configured to generate the first wired communication signal according to the first amplified signal and the second amplified signal.

[0057] The wired communication circuit 18 interacts with the host computer in a two-way manner and reports the gas concentration to the host computer, thereby realizing remote management of the on-site gas concentration.

[0058] like Figure 4 As shown, the dual-range gas detection device also includes an alarm component 19.

[0059] The alarm component 19 is connected to the control circuit 14 and is configured to alarm on the gas concentration.

[0060] Specifically, the alarm component 19 issues an alarm according to the alarm signal; the control circuit 14 is also configured to generate an alarm signal according to the first amplified signal and the second amplified signal.

[0061] The alarm component 19 is used to give an alarm for the gas concentration, thereby improving the safety of the dual-range gas detection device.

[0062] like Figure 5 As shown, the first amplifier circuit 12 includes an adjustable resistance component 121 , a first amplifier component 122 , a second amplifier component 123 and a differential amplifier component 124 .

[0063] The adjustable resistance component 121 provides a reference voltage; the first amplifying component 122 is connected to the adjustable resistance component 121, and is configured to amplify the reference voltage to generate a third amplified signal, and amplify the gas sampling signal to generate a fourth amplified signal; the second amplifying component 123 generates a reference voltage; the differential amplifying component 124 is connected to the first amplifying component 122 and the second amplifying component 123, and is configured to generate a first amplified signal according to the reference voltage, the third amplified signal and the fourth amplified signal. Specifically, the adjustable resistance component 121 generates a reference voltage according to user input.

[0064] The first amplified signal is generated according to the reference voltage, the third amplified signal and the fourth amplified signal through the differential amplifier component 124, thereby realizing the zeroing function of the dual-range gas detection device, and the positive reference voltage can be set so that the output value of the first amplified signal is in the positive range, thereby eliminating the need to provide a negative power supply for the differential amplifier component 124, realizing single power supply, and the circuit is simple and low-cost.

[0065] Figure 6 An example circuit structure of a dual-range gas detection device provided by an embodiment of the present invention is shown. For ease of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0066] The control circuit 14 includes a microprocessor U1.

[0067] The power supply terminal VCC of the microprocessor U1 is connected to the first power supply VAA, the first analog input terminal AD0 of the microprocessor U1 is the first amplified signal input terminal of the control circuit 14, the second analog input terminal AD1 of the microprocessor U1 is the second amplified signal input terminal of the control circuit 14, and the ground terminal GND of the microprocessor U1 is connected to the power ground.

[0068] The second amplifier circuit 13 includes a first operational amplifier U2 , a first resistor R1 , a second resistor R2 , and a third resistor R3 .

[0069] The first end of the first resistor R1 is the first amplified signal input end of the second amplifier circuit 13, the first end of the second resistor R2 is the reference voltage input end of the second amplifier circuit 13, the second end of the first resistor R1 is connected to the inverting input end of the first operational amplifier U2 and the first end of the third resistor R3, the second end of the second resistor R2 is connected to the non-inverting input end of the first operational amplifier U2, the output end of the first operational amplifier U2 and the second end of the third resistor R3 together constitute the second amplified signal output end of the second amplifier circuit 13, the power supply end of the first operational amplifier U2 is connected to the second power supply VBB, and the ground end of the first operational amplifier U2 is connected to the power ground.

[0070] The adjustable resistor component 121 includes an adjustable resistor R0 , a fourth resistor R4 , and a fifth resistor R5 .

[0071] A first end of the fourth resistor R4 is connected to the third power supply VCC, a second end of the fourth resistor R4 is connected to a first end of the adjustable resistor R0, an adjustment end of the adjustable resistor R0 is a reference voltage output end of the adjustable resistor component 121, a second end of the adjustable resistor R0 is connected to a first end of the fifth resistor R5, and a second end of the fifth resistor R5 is connected to a power ground.

[0072] The adjustable resistor R0 is a zero-point adjustment to ensure that when there is no gas sampling signal, the first amplified signal and the second amplified signal input to the microprocessor U1 are both 0.

[0073] The first amplifying element 122 includes a second operational amplifier U3 , a third operational amplifier U4 , a sixth resistor R6 , a seventh resistor R7 , an eighth resistor R8 , a ninth resistor R9 , a tenth resistor R10 , and an eleventh resistor R11 .

[0074] The non-inverting input terminal of the second operational amplifier U3 is connected to the first end of the sixth resistor R6 and the first end of the seventh resistor R7, the second end of the sixth resistor R6 is the gas sampling signal input terminal of the first amplifier component 122, the inverting input terminal of the second operational amplifier U3 is connected to the first end of the eighth resistor R8 and the first end of the ninth resistor R9, the output terminal of the second operational amplifier U3 and the second end of the eighth resistor R8 jointly constitute the fourth amplified signal output terminal of the first amplifier component 122, the second end of the ninth resistor R9 is connected to the first end of the tenth resistor R10 and the inverting input terminal of the third operational amplifier U4, the second end of the tenth resistor R10 and the output terminal of the third operational amplifier U4 jointly constitute the third amplified signal output terminal of the first amplifier component 122, the first end of the eleventh resistor R11 is connected to the non-inverting input terminal of the third operational amplifier U4, the second end of the eleventh resistor R11 is the reference voltage input terminal of the first amplifier component 122, and the second end of the seventh resistor R7 is connected to the power ground.

[0075] The second amplifying element 123 includes a fourth operational amplifier U5 , a first capacitor C1 , a twelfth resistor R12 , and a thirteenth resistor R13 .

[0076] The non-inverting input terminal of the fourth operational amplifier U5 is connected to the first end of the twelfth resistor R12 and the first end of the thirteenth resistor R13, the second end of the twelfth resistor R12 is connected to the fourth power supply VDD, the inverting input terminal of the fourth operational amplifier U5 and the output terminal of the fourth operational amplifier U5 jointly constitute the reference voltage output terminal of the second amplifying component 123, the power supply terminal of the fourth operational amplifier U5 and the first end of the first capacitor C1 are commonly connected to the third power supply VCC, and the ground terminal of the fourth operational amplifier U5 and the second end of the thirteenth resistor R13 are commonly connected to the power ground.

[0077] The differential amplifier 124 includes a fifth operational amplifier U6 , a fourteenth resistor R14 , a fifteenth resistor R15 , a sixteenth resistor R16 , and a seventeenth resistor R17 .

[0078] The first end of the fourteenth resistor R14 is the third amplified signal input terminal of the differential amplifier component 124, the inverting input terminal of the fifth operational amplifier U6 is connected to the second end of the fourteenth resistor R14 and the first end of the seventeenth resistor R17, the first end of the fifteenth resistor R15 is the fourth amplified signal input terminal of the differential amplifier component 124, the first end of the sixteenth resistor R16 is the reference voltage input terminal of the differential amplifier component 124, the second end of the fifteenth resistor R15 is connected to the second end of the sixteenth resistor R16 and the non-inverting input terminal of the fifth operational amplifier U6, and the output terminal of the fifth operational amplifier U6 and the second end of the seventeenth resistor R17 together constitute the first amplified signal output terminal of the differential amplifier component 124.

[0079] The following is a combination of working principles Figure 6 As shown for further explanation:

[0080] The adjustable resistor R0, the fourth resistor R4 and the fifth resistor R5 generate a reference voltage according to user input; the third operational amplifier U4 amplifies the reference voltage to generate a third amplified signal, and the second operational amplifier U3 amplifies the gas sampling signal to generate a fourth amplified signal; the fourth operational amplifier U5 generates a reference voltage; the third amplified signal is input to the inverting input terminal of the fifth operational amplifier U6, and the reference voltage and the fourth amplified signal are input to the non-inverting input terminal of the fifth operational amplifier U6, and the fifth operational amplifier U6 performs differential amplification according to the reference voltage, the third amplified signal and the fourth amplified signal to generate a first amplified signal.

[0081] The first operational amplifier U2 amplifies the first amplified signal to generate a second amplified signal.

[0082] The sixth operational amplifier U7 in the first follower 16 follows the first amplified signal, and the seventh operational amplifier U8 in the second follower 17 follows the second amplified signal. The followed first amplified signal is input to the first analog input terminal AD0 of the microprocessor U1, and the followed second amplified signal is input to the second analog input terminal AD1 of the microprocessor U1.

[0083] When the voltage value of the second amplified signal is greater than the preset threshold, the microprocessor U1 generates a display signal according to the first amplified signal, and when the voltage value of the second amplified signal is less than or equal to the preset threshold, the microprocessor U1 generates a display signal according to the second amplified signal. The display component 15 displays according to the display signal.

[0084] An embodiment of the present invention further provides a gas detector, wherein the electric energy meter includes the above-mentioned dual-range gas detection device.

[0085] In the embodiment of the present invention, the gas concentration is detected by a gas sensor to generate a gas sampling signal; the first amplifying circuit amplifies the gas sampling signal to generate a first amplified signal; the second amplifying circuit amplifies the first amplified signal to generate a second amplified signal; the control circuit generates a display signal according to the first amplified signal and the second amplified signal respectively; the display component displays according to the display signal; since the gas sampling signal is amplified in two stages, and the amplified signals after the first amplification and the second amplification are respectively input to the control circuit, the control circuit generates a display signal according to the first amplified signal after the first amplification or the second amplified signal after the second amplification according to the comparison result of the voltage value of the second amplified signal after the second amplification and the preset threshold value, thereby realizing dual-range detection when one gas sensor is configured.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual-range gas detection device, characterized in that: The dual-range gas detection device comprises: a gas sensor configured to detect a gas concentration to generate a gas sampling signal; A first amplifying circuit connected to the gas sensor and configured to amplify the gas sampling signal to generate a first amplified signal; a second amplifying circuit connected to the first amplifying circuit and configured to amplify the first amplified signal to generate a second amplified signal; A control circuit connected to the first amplifying circuit and the second amplifying circuit, and configured to generate a display signal according to the first amplified signal and the second amplified signal respectively; A display component connected to the control circuit and configured to display according to a display signal; The control circuit includes a microprocessor; The power supply terminal of the microprocessor is connected to the first power supply, the first analog input terminal of the microprocessor is the first amplified signal input terminal of the control circuit, the second analog input terminal of the microprocessor is the second amplified signal input terminal of the control circuit, and the ground terminal of the microprocessor is connected to the power ground; The second amplifying circuit includes a first operational amplifier, a first resistor, a second resistor and a third resistor; The first end of the first resistor is the first amplified signal input end of the second amplifying circuit, the first end of the second resistor is the reference voltage input end of the second amplifying circuit, the second end of the first resistor is connected to the inverting input end of the first operational amplifier and the first end of the third resistor, the second end of the second resistor is connected to the non-inverting input end of the first operational amplifier, the output end of the first operational amplifier and the second end of the third resistor together constitute the second amplified signal output end of the second amplifying circuit, the power supply end of the first operational amplifier is connected to the second power supply VBB, and the ground end of the first operational amplifier is connected to the power ground; The first amplifying circuit comprises: An adjustable resistance component providing a reference voltage; A first amplifying component connected to the adjustable resistance component and configured to amplify the reference voltage to generate a third amplified signal, and amplify the gas sampling signal to generate a fourth amplified signal; a second amplifying component generating a reference voltage; A differential amplifier component connected to the first amplifier component and the second amplifier component, configured to generate the first amplified signal according to the reference voltage, the third amplified signal and the fourth amplified signal; The adjustable resistor component includes an adjustable resistor, a fourth resistor and a fifth resistor; The first end of the fourth resistor is connected to the third power supply, the second end of the fourth resistor is connected to the first end of the adjustable resistor, the adjustment end of the adjustable resistor is the reference voltage output end of the adjustable resistor component, the second end of the adjustable resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is connected to the power ground; The first amplifying component includes a second operational amplifier, a third operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor and an eleventh resistor; The non-inverting input terminal of the second operational amplifier is connected to the first end of the sixth resistor and the first end of the seventh resistor, the second end of the sixth resistor is the gas sampling signal input terminal of the first amplifier component, the inverting input terminal of the second operational amplifier is connected to the first end of the eighth resistor and the first end of the ninth resistor, the output terminal of the second operational amplifier and the second end of the eighth resistor jointly constitute the fourth amplified signal output terminal of the first amplifier component, the second end of the ninth resistor is connected to the first end of the tenth resistor and the inverting input terminal of the third operational amplifier, the second end of the tenth resistor and the output terminal of the third operational amplifier jointly constitute the third amplified signal output terminal of the first amplifier component, the first end of the eleventh resistor is connected to the non-inverting input terminal of the third operational amplifier, the second end of the eleventh resistor is the reference voltage input terminal of the first amplifier component, and the second end of the seventh resistor is connected to the power supply ground; the second amplifier component includes a fourth operational amplifier, a first capacitor, a twelfth resistor and a thirteenth resistor; The non-inverting input terminal of the fourth operational amplifier is connected to the first terminal of the twelfth resistor and the first terminal of the thirteenth resistor, the second terminal of the twelfth resistor is connected to the fourth power supply, the inverting input terminal of the fourth operational amplifier and the output terminal of the fourth operational amplifier together constitute the reference voltage output terminal of the second amplifying component, the power supply terminal of the fourth operational amplifier and the first terminal of the first capacitor are connected to the third power supply, and the ground terminal of the fourth operational amplifier and the second terminal of the thirteenth resistor are connected to the power ground; the differential amplifying component includes a fifth operational amplifier, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor and a seventeenth resistor; The first end of the fourteenth resistor is the third amplified signal input terminal of the differential amplifier component, the inverting input terminal of the fifth operational amplifier is connected to the second end of the fourteenth resistor and the first end of the seventeenth resistor, the first end of the fifteenth resistor is the fourth amplified signal input terminal of the differential amplifier component, the first end of the sixteenth resistor is the reference voltage input terminal of the differential amplifier component, the second end of the fifteenth resistor is connected to the second end of the sixteenth resistor and the non-inverting input terminal of the fifth operational amplifier, and the output terminal of the fifth operational amplifier and the second end of the seventeenth resistor together constitute the first amplified signal output terminal of the differential amplifier component.

2. The dual-range gas detection device according to claim 1, characterized in that: The dual-range gas detection device also includes: a first follower connected between the first amplifying circuit and the control circuit; and A first follower is connected between the second amplifying circuit and the control circuit.

3. The dual-range gas detection device according to claim 1, characterized in that: The dual-range gas detection device also includes: The control circuit is connected to the control circuit and is configured as a wired communication circuit for bidirectional interaction with the host computer.

4. The dual-range gas detection device according to claim 1, characterized in that: The dual-range gas detection device also includes: An alarm component is connected to the control circuit and configured to alarm the gas concentration.

5. The dual-range gas detection device according to claim 1, characterized in that: The control circuit is specifically configured to generate the display signal according to the first amplified signal when the voltage value of the second amplified signal is greater than a preset threshold, and to generate the display signal according to the second amplified signal when the voltage value of the second amplified signal is less than or equal to the preset threshold.

6. A gas detector, characterized in that: The gas detector comprises a dual-range gas detection device as described in any one of claims 1 to 5.

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