Intrinsic safety power supply circuit and fuel electrochemical oxygen analyzer

Abstract

The utility model discloses an intrinsic safety power supply circuit and a fuel electrochemical oxygen analyzer. The intrinsic safety power supply circuit comprises a first MOS tube, a first capacitor, a second capacitor, a first resistor, a first Schottky diode, a first Zener diode and a second Zener diode, the power supply module of the fuel electrochemical oxygen analyzer comprises the intrinsic safety power supply circuit and further comprises a sensor module, an AD conversion module, a key module, a single chip microcomputer module, an analog output module and a display driving module which are connected with the power supply module, and the single chip microcomputer module is connected with the AD conversion module, the key module, the analog output module and the display driving module. The sensor module is connected with the AD conversion module, and the analog output module is connected with external equipment; the fuel electrochemical oxygen analyzer adopts the intrinsically safe power supply circuit to limit the working current and voltage in the circuit so as to control the power consumption of the whole machine, so that explosion prevention is realized, and the fuel electrochemical oxygen analyzer can measure the oxygen concentration in a flammable and explosive environment.

Description

Technical Field

[0001] This application relates to the field of trace oxygen measurement technology, specifically to an intrinsically safe power supply circuit and a fuel electrochemical oxygen analyzer. Background Technology

[0002] In petroleum, chemical, and natural gas industries, abnormal oxygen concentrations often indicate potential explosion hazards. Therefore, oxygen analyzers are needed to measure and analyze the oxygen content in real time. These analyzers must meet explosion-proof requirements, utilizing advanced fuel cell oxygen sensor technology to detect oxygen concentration in the working gas in real time, ensuring safe production in potentially explosive environments. Explosion-proof fuel electrochemical oxygen analyzers are intrinsically safe. The explosion-proof principle of intrinsically safe electrical equipment is to limit the spark discharge energy and thermal energy of the circuit by restricting various parameters or taking protective measures, ensuring that the sparks and thermal effects generated under normal operation and specified fault conditions cannot ignite the explosive mixture in the surrounding environment, thus achieving electrical explosion-proof. The circuit of such electrical equipment itself has explosion-proof properties, meaning it is inherently safe, hence the name intrinsically safe.

[0003] Therefore, there is an urgent need for an intrinsically safe power supply circuit and a fuel electrochemical oxygen analyzer that can limit the maximum output power of the power supply to achieve intrinsic safety and thus realize explosion protection. Utility Model Content

[0004] To address the aforementioned issues, this application provides an intrinsically safe power supply circuit and a fuel electrochemical oxygen analyzer. The circuit section employs an intrinsically safe design, limiting the circuit's output voltage and current, and limiting the power supply's maximum output power to control the overall power consumption, thereby achieving explosion protection. The fuel electrochemical oxygen analyzer is easy to install and can measure oxygen concentration in flammable and explosive environments.

[0005] The technical solution adopted in this application is:

[0006] This application provides an intrinsically safe power supply circuit, including a first MOSFET, a first capacitor, a second capacitor, a first resistor, a first Schottky diode, a first Zener diode, and a second Zener diode;

[0007] The anode of the first Schottky diode is connected to the second terminal of the socket, and the cathode is connected to the drain of the first MOSFET. One end of the first capacitor is connected to the cathode of the first Schottky diode, and the other end is connected to the first terminal of the socket. One end of the first resistor is connected to the cathode of the first Schottky diode, and the other end is connected to the gate of the first MOSFET and the cathode of the first Zener diode. The source of the first MOSFET and the cathode of the second Zener diode are connected. The anode of the second Zener diode is connected to the anode of the first Zener diode and grounded. The second capacitor and the second Zener diode are connected in parallel and then grounded.

[0008] The first Zener diode is used to control the gate voltage VG of the first MOSFET Q1. The first resistor is used to limit the current through the first Zener diode. The first MOSFET operates in the saturation region when VGS-VDS < Vth.

[0009] Furthermore, there are multiple Schottky diodes connected in series.

[0010] Furthermore, the number of Zener diodes is ≥3, and at least two Zener diodes are connected in parallel with the second capacitor and then grounded.

[0011] This application also provides a fuel electrochemical oxygen analyzer, including a power module and a housing. The power module is used to supply power to various modules connected to it. The power module includes the intrinsically safe power circuit described above. The housing includes a base, a main board, and a sensor module. The housing is provided with a display screen, a button module, and a power interface. The circuit module is disposed on the main board. The sensor module includes a sensor assembly and a sensor signal board. The sensor assembly is disposed on the base, and the sensor signal board is disposed on the sensor assembly. The main board is vertically disposed between the display screen and the sensor module. The main board also includes an AD module, a microcontroller module, an analog output module, and a display driver module. The display driver module of the main board is connected to the display screen. The power module is connected to the power interface on the housing. The microcontroller module is connected to the AD conversion module, the button module, the analog output module, and the display driver module. The sensor module is connected to the AD conversion module.

[0012] Furthermore, the housing is divided into a front cover and a rear cover. The display screen and button module are located on the front cover, and the power interface is located on the rear cover. The rear cover also has a vent. A back panel sealing strip is fitted between the front cover and the rear cover. A display screen window is provided at the rear of the display screen. A window sealing ring is provided between the display screen window and the display screen. A display screen base is provided below the display screen window. The motherboard and the display screen base are fixedly connected by a first screw. A base sealing strip is provided below the base. The front cover and the rear cover are fixedly connected to the base by a third screw.

[0013] Furthermore, a display cover is also provided on the front cover. The display cover is fixedly connected to the front cover by the fifth screw, and the motherboard is fixedly connected to the front cover by the fourth screw passing through the display window and the display base.

[0014] Further, the analog output module includes an analog output chip, an operational amplifier, a fourteenth resistor, a sixteenth resistor, and a seventeenth resistor. The sixth output pin of the analog output chip is connected to the output terminal and the inverting input terminal of the operational amplifier. The seventh output pin of the analog output chip is connected to the non-inverting input terminal of the operational amplifier. One end of the fourteenth resistor is connected to the GND pin of the analog output chip, the other end of the fourteenth resistor is connected to one end of the sixteenth resistor, the other end of the sixteenth resistor is connected to one end of the seventeenth resistor and the inverting input terminal of the operational amplifier, and the other end of the seventeenth resistor is connected to the output terminal of the operational amplifier and the sixth output pin of the analog output chip;

[0015] The resistance value of the sixteenth resistor is more than ten times that of the fourteenth resistor, and the resistance value of the seventeenth resistor is twice that of the sixteenth resistor. The operational amplifier amplifies the voltage drop generated by the current flowing through the fourteenth resistor by 2 times and then feeds it back to the analog output chip

[0016] Specifically, the analog output chip uses a GP8102 chip, and the operational amplifier specifically uses an operational amplifier KTA333.

[0017] Further, the air outlet is sleeved with a ferrule straight-through for gas transmission. <00,00037>

[0018] Advantages of this application:

[0019] 1. The intrinsically safe power supply circuit of this application clamps the gate voltage VG at 13V through the Zener diode ZD1, and combines the self-current limiting characteristic of the MOS transistor in the saturation region, that is, VGS - VDS < Vth, to ensure that the circuit cannot generate enough energy to ignite the combustible gas in the dangerous environment during short circuit or overcurrent; and generates a stable voltage of about 10V between the input voltage VCC and the ground GND to provide a constant power supply for the analog output module U4, avoiding abnormal power supply caused by input fluctuations or load changes.

[0020] 2. The fuel electrochemical oxygen analyzer of this application uses an intrinsically safe power supply circuit, can measure the oxygen concentration in flammable and explosive environments, and is easy to install.

[0021] 3. The analog output module of this application can easily obtain the voltage drop generated by the current flowing through the resistor R14, and amplifies the voltage drop generated by the current flowing through the resistor R14 by 2 times and then feeds it back to the sixth pin of the analog output chip U4 for feedback, ensuring the stability of the closed loop, making the voltage output by the analog output chip always within the predetermined range value, effectively avoiding faults and sparks, and reducing the explosion risk. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of an intrinsically safe power supply circuit provided by some embodiments of this application.

[0023] Figure 2 This is a schematic diagram of the front cover structure of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0024] Figure 3 This is a schematic diagram of the back cover structure of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0025] Figure 4 This is a schematic cross-sectional view of the internal structure of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0026] Figure 5 This application provides an embodiment of a fuel electrochemical oxygen analyzer with a display screen cover installed on the front cover.

[0027] Screw installation diagram.

[0028] Figure 6 This is a schematic diagram of the rear cover screw installation of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0029] Figure 7 This is a structural block diagram of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0030] Figure 8 The circuit diagram shows an AD conversion module of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0031] Figure 9 The circuit diagram shows the analog output module of a fuel electrochemical oxygen analyzer provided for some embodiments of this application.

[0032] In the diagram, 1 is the front cover, 2 is the back cover, 3 is the power interface, 4 is the card sleeve through, 5 is the sensor assembly, 6 is the display screen, 7 is the button module, 8 is the back panel sealing strip, 9 is the main board, 10 is the window sealing ring, 11 is the display screen window, 12 is the first screw, 13 is the display screen base, 14 is the second screw, 15 is the sensor signal board, 16 is the sealing O-ring, 17 is the base sealing strip, 18 is the third screw, 19 is the fourth screw, 20 is the fifth screw, 21 is the display screen cover, and 22 is the sixth screw. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings and a preferred embodiment.

[0034] refer to Figure 1One embodiment of this application provides an intrinsically safe power supply circuit, including a first MOSFET Q1, a first capacitor C1, a second capacitor C2, a first resistor R1, a first Schottky diode D1, a second Schottky diode D2, a third Schottky diode D3, a first Zener diode ZD1, a second Zener diode ZD2, and a third Zener diode ZD3. Specifically, the first resistor R1 has a resistance of 220KΩ, the first capacitor C1 has a resistance of 10nF, and the second capacitor C2 has a resistance of 100nF. Both the resistor and the capacitor are used for current limiting.

[0035] The first Schottky diode D1, the second Schottky diode D2, and the third Schottky diode D3 are connected in series. The anode of the first Schottky diode D1 is connected to the second terminal of the socket. The cathode of the third Schottky diode D3 is connected to the drain of the first MOSFET Q1. One end of the first capacitor C1 is connected to the cathode of the third Schottky diode D3, and the other end is connected to the first terminal of the socket. One end of the first resistor R1 is connected to the cathode of the third Schottky diode D9, and the other end is connected to the gate of the first MOSFET and the cathode of the first Zener diode ZD1. The source of the first MOSFET Q1 is connected to the cathode of the second Zener diode ZD2. The anode of the second Zener diode ZD2 is connected to the anode of the first Zener diode ZD1 and grounded. The third Zener diode ZD3 and the second capacitor C2 are connected in parallel with the second Zener diode ZD2 and then grounded.

[0036] Specifically, the first Schottky diode D1, the second Schottky diode D2, and the third Schottky diode D3 are of the SS14 type, the first Zener diode ZD1 is of the SML4743 type, the second Zener diode ZD2 and the third Zener diode ZD3 are of the SML4742 type, and the first MOSFET Q1 is of the NCE6005 type.

[0037] The intrinsically safe power supply circuit is used to provide a power supply voltage for the analog output module, ensuring that the analog output module operates under stable voltage conditions. After power-on, taking the loop output of 20 mA as an example, at this time, the drain voltage VD of MOS transistor Q1 is 21 V. For MOS transistor Q1 to conduct, it needs to satisfy VGS > Vth, where VGS is the voltage difference between the gate (G) and the source (S), and Vth is the minimum VGS required for the first MOS transistor Q1 to start conducting. The Vth of this type of MOS transistor is 2.5 V, that is, the source voltage VS of MOS transistor Q1 < 10.5 V. The Zener diode ZD1 controls the gate voltage VG of MOS transistor Q1 to be 13 V. The first resistor R1 is used to limit the current passing through the Zener diode ZD1, thereby protecting ZD1. The VGS - VDS of the first MOS transistor Q1 = (VG - VS) - (VD - VS) = VG - VD = 13 - 21 = -8 V < Vth = 2.5 V. It can be seen that MOS transistor Q1 operates in the saturation region, where VDS is the voltage difference between the drain (D) and the source (S). According to the saturation region current formula, that is , when ID is the maximum, is the maximum, then VS is the minimum. At this time, the source voltage VS of Q1 is still greater than 10 V, meeting the power supply requirements of the subsequent device U4. Therefore, the intrinsically safe power supply circuit generates a voltage of about 10 V between GND and the VCC input by the socket J6. The first capacitor C1 and the second capacitor C2 play a filtering role. The first Schottky diode D1, the second Schottky diode D2, and the third Schottky diode D3 make the Schottky diode cut off when the power supply is reversely connected, thereby protecting other devices in the subsequent circuit from being damaged. The second Zener diode ZD2 and the third Zener diode ZD3 limit the maximum power of the power supply, and can avoid the damage of the remaining devices in the case of a front-end circuit fault; the reason for using multiple Schottky diodes and Zener diodes is that a dual protection function is required when a fault occurs in the intrinsically safe power supply circuit, meeting the requirements of the intrinsically safe circuit design.

[0038] The intrinsically safe power supply circuit of this application clamps the gate voltage VG at 13 V through the Zener diode ZD1. The regulated voltage value of 13 V of the Zener diode for the gate, the threshold voltage of 2.5 V of the MOS transistor Q1, and the resistor R1 jointly limit the range of VGS, preventing VS from decreasing excessively. Even when ID reaches the maximum value, the fixation of VG and the self-current limiting characteristic of the saturation region also ensure that VS will not drop below 10 V, thus meeting the power supply requirements of U4. Combining the self-current limiting characteristic of the saturation region of the MOS transistor, that is, VGS - VDS < Vth, ensures that the circuit cannot generate enough energy to ignite the combustible gas in a dangerous environment during a short circuit or overcurrent; and generates a stable voltage of about 10 V between the input voltage VCC and the ground GND, providing a constant power supply for the analog output module U4, avoiding abnormal power supply caused by input fluctuations or load changes.

[0039] Reference Figures 2-6Another embodiment of this application provides a fuel electrochemical oxygen analyzer, including a power module and a housing. The power module employs the intrinsically safe power supply circuit described in the above embodiments. The power module is used to supply power to various modules connected to it. (Refer to...) Figure 2 and Figure 3 The housing consists of a front cover 1 and a rear cover 2. The display screen 6 and button module 7 are located on the front cover 1, and the power interface 3 is located on the rear cover 2. A vent is also located at the bottom of the rear cover 2, and a retaining sleeve 4 is fitted over the vent for transporting gas. (Reference) Figure 4 A back panel sealing strip 8 is fitted between the front cover 1 and the rear cover 2 for sealing. Behind the display screen 6, a display screen window 11 is provided inside the housing. A window sealing ring 10 is provided between the display screen window 11 and the display screen 6. A display screen base 13 is provided below the display screen window 11 for supporting the display screen 6. The main board 9 and the display screen base 13 are fixedly connected by the first screw 12.

[0040] Continue to refer to Figure 4 The housing includes a base, a main board 9, and a sensor module. The circuit module is mounted on the main board 9. The sensor module includes a sensor assembly 5 and a sensor signal board 15. The sensor assembly 5 is mounted on the base, and the sensor signal board 15 is mounted on the sensor assembly 5. The main board 9 is vertically mounted between the display screen 6 and the sensor module. The main board 9 also includes an AD module, a microcontroller module, an analog output module, and a display driver module. The display driver module of the main board 9 is connected to the display screen 6. The power module is connected to the power interface 3 on the housing. A base sealing strip 17 and a sealing O-ring 16 are provided below the base for waterproof sealing. The front cover 1 and the rear cover 2 are fixedly connected to the base by a third screw 18, and the lower part of the front cover 1 and the rear cover 2 are fixedly connected by a second screw 14.

[0041] refer to Figure 5 and Figure 6 The front cover 1 is also provided with a display screen cover 21. The display screen cover 21 is fixedly connected to the front cover 1 by the fifth screw 20. The main board 9 is fixedly connected to the front cover 1 by the fourth screw 19 through the display screen window 11 and the display screen base 13. The upper part of the front cover 1 and the upper part of the rear cover 2 are fixed by the sixth screw 22.

[0042] Specifically, considering the installation requirements of each component, the first screw 12 is an M3x6 stainless steel Phillips head combination screw, the second screw 14 is an M4*8 Phillips head waterproof screw with a sealing ring, the third screw 18 is an M4x20 304 stainless steel internal hex socket head cap screw, the fourth screw 19 is an M3x6 black 304 stainless steel Phillips head countersunk screw, the fifth screw 20 is an M2x4 black 304 stainless steel Phillips head countersunk screw, and the sixth screw 22 is an M4x25 stainless steel Phillips head cap screw with a washer.

[0043] During installation, first install the components on the front cover 1 and the rear cover 2 respectively, then install the base and sensor assembly 5, as well as the front cover 1 and the rear cover 2, and finally install the front cover 1 and the rear cover 2. It is quick and convenient.

[0044] In some other embodiments, reference is made to Figure 7 The microcontroller module is connected to the AD conversion module, button module 7, analog output module and display driver module. The sensor module is connected to the AD conversion module. The microcontroller module specifically adopts HC32L136.

[0045] refer to Figure 8 The AD conversion module includes an AD conversion chip U1 and an operational amplifier U2. The AD conversion chip U1 is a 16-bit AD conversion chip MS1112, and the operational amplifier U2 is an operational amplifier KTA333. The analog signal acquired by the sensor module is sent to the AD conversion module, which then transmits the digital signal to the microcontroller module. Other peripheral circuits are existing technologies, such as... Figure 8 As shown.

[0046] refer to Figure 9 The analog output module includes an analog output chip U4, an operational amplifier U5, a fourteenth resistor R14, a sixteenth resistor R16, and a seventeenth resistor R17. The analog output chip U4 uses a GP8102 chip, and the operational amplifier U5 specifically uses an operational amplifier KTA333. The sixth output pin of the analog output chip U4 is connected to the output terminal and the inverting input terminal of the operational amplifier U5. The seventh output pin of the analog output chip U4 is connected to the non-inverting input terminal of the operational amplifier U5. One end of the fourteenth resistor R14 is connected to the GND pin of the analog output chip U4, and the other end of the fourteenth resistor R14 is connected to one end of the sixteenth resistor R16. The other end of the sixteenth resistor R16 is connected to one end of the seventeenth resistor R17 and the inverting input terminal of the operational amplifier U5. The other end of the seventeenth resistor R17 is connected to the output terminal of the operational amplifier U5 and the sixth output pin of the analog output chip U4.

[0047] The total current output to the analog output module is the sum of the currents flowing through the fourteenth resistor R14 and the sixteenth resistor R16. The fourteenth resistor R14 = 100Ω, the sixteenth resistor R16 = 750kΩ, and the seventeenth resistor R17 = 1500kΩ. The resistance of the sixteenth resistor R16 is ten times greater than that of the fourteenth resistor R14. The difference in current flowing through the fourteenth resistor R14 and the sixteenth resistor R16 is 7500 times, so the current flowing through the sixteenth resistor R16 can be ignored. The resistance of the seventeenth resistor R17 is twice that of the sixteenth resistor R16, making it easy to obtain the voltage drop generated by the current flowing through the fourteenth resistor R14. The function of the operational amplifier U5 is to amplify the voltage drop generated by the current flowing through the fourteenth resistor R14 by 2 times and then feed it back to pin 6 of the analog output chip U4 for feedback, ensuring the stability of the closed loop and keeping the voltage output by the analog output chip within the predetermined range.

[0048] The analog output module also includes a thirteenth resistor R13. When the system output current is at its maximum, the resistance of the thirteenth resistor R13 is 330Ω, and the current flowing through the thirteenth resistor R13 is close to 20mA. Therefore, the thirteenth resistor R13 is selected in a large package for heat dissipation.

[0049] Preferably, the analog output module also includes a fourth transient voltage suppressor diode TVS4, a fifth transient voltage suppressor diode TVS5, a sixth transient voltage suppressor diode TVS6, a seventh transient voltage suppressor diode TVS7, a twenty-eighth capacitor C28, and a twenty-ninth capacitor C29. The fourth and fifth transient voltage suppressor diodes TVS4 and TVS5 are of the SMAZ6V2 type, and the sixth and seventh transient voltage suppressor diodes TVS6 and TVS7 are of the SMAZ5V6 type. The fourth, fifth, sixth, and seventh transient voltage suppressor diodes TVS4, TVS5, TVS6, and TVS7 are connected to the analog output chip U4 to protect the analog output chip U4.

[0050] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications are also within the protection scope of this application.

Claims

1. An intrinsically safe power supply circuit, characterized in that, It includes a first MOSFET, a first capacitor, a second capacitor, a first resistor, a first Schottky diode, a first Zener diode, and a second Zener diode; The anode of the first Schottky diode is connected to the second terminal of the socket, and the cathode is connected to the drain of the first MOSFET. One end of the first capacitor is connected to the cathode of the first Schottky diode, and the other end is connected to the first terminal of the socket. One end of the first resistor is connected to the cathode of the first Schottky diode, and the other end is connected to the gate of the first MOSFET and the cathode of the first Zener diode. The source of the first MOSFET and the cathode of the second Zener diode are connected. The anode of the second Zener diode is connected to the anode of the first Zener diode and grounded. The second capacitor and the second Zener diode are connected in parallel and then grounded. The first Zener diode is used to control the gate voltage VG of the first MOSFET Q1. The first resistor is used to limit the current through the first Zener diode. The first MOSFET operates in the saturation region when VGS-VDS < Vth.

2. The intrinsically safe power supply circuit according to claim 1, characterized in that, There are multiple Schottky diodes connected in series.

3. The intrinsically safe power supply circuit according to claim 1, characterized in that, The number of Zener diodes is ≥3, and at least two Zener diodes are connected in parallel with the second capacitor and then grounded.

4. A fuel electrochemical oxygen analyzer, comprising a power module and a housing, wherein the power module supplies power to various modules connected thereto, characterized in that, The power supply module includes the intrinsically safe power supply circuit as described in any one of claims 1-3. The housing includes a base, a main board (9), and a sensor module. The housing is provided with a display screen (6), a button module (7), and a power interface (3). The circuit module is disposed on the main board (9). The sensor module includes a sensor assembly (5) and a sensor signal board (15). The sensor assembly (5) is disposed on the base, and the sensor signal board (15) is disposed on the sensor assembly (5). The main board (9) is vertically disposed between the display screen (6) and the sensor module. The main board (9) also includes an AD module, a microcontroller module, an analog output module, and a display driver module. The display driver module of the main board (9) is connected to the display screen (6). The power supply module is connected to the power interface (3) on the housing. The microcontroller module is connected to the AD conversion module, the button module (7), the analog output module, and the display driver module. The sensor module is connected to the AD conversion module.

5. The fuel electrochemical oxygen analyzer according to claim 4, characterized in that, The housing is divided into a front cover (1) and a rear cover (2). The display screen (6) and the button module (7) are set on the front cover (1). The power interface (3) is set on the rear cover (2). The rear cover (2) is also provided with an air vent. A back plate sealing strip (8) is fitted between the front cover (1) and the rear cover (2). The display screen (6) is provided with a display screen window (11) at the rear. A window sealing ring (10) is provided between the display screen window (11) and the display screen (6). A display screen base (13) is provided below the display screen window (11). The main board (9) and the display screen base (13) are fixedly connected by the first screw (12). A base sealing strip (17) is provided below the base. The front cover (1) and the rear cover (2) are fixedly connected to the base by the third screw (18).

6. The fuel electrochemical oxygen analyzer according to claim 5, characterized in that, The front cover (1) is also provided with a display cover (21). The display cover (21) is fixedly connected to the front cover (1) by the fifth screw (20). The main board (9) is fixedly connected to the front cover (1) after passing through the display window (11) and the display base (13) by the fourth screw (19).

7. The fuel electrochemical oxygen analyzer according to claim 4, characterized in that, The analog output module includes an analog output chip, an operational amplifier, a fourteenth resistor, a sixteenth resistor, and a seventeenth resistor. The sixth output pin of the analog output chip is connected to the output terminal and the inverting input terminal of the operational amplifier. The seventh output pin of the analog output chip is connected to the non-inverting input terminal of the operational amplifier. One end of the fourteenth resistor is connected to the GND pin of the analog output chip. The other end of the fourteenth resistor is connected to one end of the sixteenth resistor. The other end of the sixteenth resistor is connected to one end of the seventeenth resistor and the inverting input terminal of the operational amplifier. The other end of the seventeenth resistor is connected to the output terminal of the operational amplifier and the sixth output pin of the analog output chip. The resistance of the sixteenth resistor is ten times greater than that of the fourteenth resistor, and the resistance of the seventeenth resistor is twice that of the sixteenth resistor. The operational amplifier amplifies the voltage drop generated by the current flowing through the fourteenth resistor by a factor of 2 and feeds it back to the analog output chip.

8. The fuel electrochemical oxygen analyzer according to claim 7, characterized in that, The analog output chip uses the GP8102 chip, and the operational amplifier specifically uses the KTA333 operational amplifier.

9. The fuel electrochemical oxygen analyzer according to claim 5, characterized in that, The outlet is fitted with a clamping sleeve (4) for gas transmission.

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