Automobile electromagnetic compatibility test load box

Abstract

The application discloses a kind of automobile electromagnetic compatibility test load boxes, it is related to automobile parts test field;Load box includes box, electromagnetic compatibility test circuit and control unit;Based on the test condition of control unit adjustment electromagnetic compatibility test circuit;Electromagnetic compatibility test circuit is housed in box, and electromagnetic compatibility test circuit includes analog sensor circuit, analog drive motor circuit, analog high-low side output circuit, analog blower circuit and power supply circuit module;Analog sensor circuit includes voltage sensor and resistance sensor;Voltage sensor or resistance sensor is selected based on different test requirements to test;Based on the working condition of analog blower circuit analog blower;Based on power supply circuit module, analog sensor circuit, analog drive motor circuit, analog high-low side output circuit and analog blower circuit are powered.Through module replacement actual load equipment, not only simplify test configuration, but also reduce cost expenditure.

Description

Technical Field

[0001] This application relates to the field of automotive component testing, and in particular to an automotive electromagnetic compatibility test load box. Background Technology

[0002] With the development of automotive electronics technology, ensuring the electromagnetic compatibility of products has become a key design factor.

[0003] However, existing technologies for EMC (electromagnetic compatibility) reliability testing, such as for air conditioner actuator control, typically require the use of actual blowers, motors, and sensors, resulting in high test configuration costs and bulky equipment, which affects test efficiency and flexibility. Utility Model Content

[0004] To address the aforementioned problems, this application provides an automotive electromagnetic compatibility test load box, comprising:

[0005] Box;

[0006] Electromagnetic compatibility (EMC) testing circuit, housed within the enclosure, comprising:

[0007] An analog sensor circuit, comprising voltage-type sensors and resistive sensors, is used to select either a voltage-type sensor or a resistive sensor for testing based on different testing requirements.

[0008] A simulated drive motor circuit is used to simulate different operating states of a motor.

[0009] A simulated high-side and low-side output circuit is used to simulate the high-side or low-side output function of the control unit on the load.

[0010] A simulated blower circuit is used to simulate the operation of a blower.

[0011] The power supply circuit module provides power to the analog sensor circuit, the analog drive motor circuit, the analog high and low side output circuit, and the analog blower circuit.

[0012] The control unit adjusts the test conditions of the electromagnetic compatibility test circuit based on the control unit.

[0013] In an optional embodiment, the power supply circuit module includes a fuse, a first light-emitting diode (LED), and a first resistor; the fuse is connected to the positive terminal of the first LED; the negative terminal of the first LED is connected to one end of the first resistor, and the other end of the first resistor is grounded.

[0014] In an optional embodiment, the power supply circuit module includes a battery terminal and a first switch; the battery terminal is connected to the side of a fuse away from the first light-emitting diode via the first switch; the analog sensor circuit, analog drive motor circuit, analog high and low side output circuit, and analog blower circuit are powered based on the voltage division between the first switch and the fuse.

[0015] In an optional embodiment, the analog sensor circuit includes a J10 plug-in, a J19 plug-in, and a J25 plug-in; the first end of the J10 plug-in is connected to the power supply circuit module; the second end of the J10 plug-in is connected to multiple interfaces of the J19 plug-in through multiple adjustable resistors; the second end of the J10 plug-in is connected to the first end of the J25 plug-in; and the second end of the J25 plug-in is grounded.

[0016] In an optional embodiment, the simulated blower circuit includes a second light-emitting diode, a second resistor, a third resistor, and a J1 plug-in; the second end of the J1 plug-in is connected to the negative terminal of the second light-emitting diode and one end of the second resistor; the other end of the second resistor and the positive terminal of the second light-emitting diode are connected to one end of the third resistor; the other end of the third resistor is connected to the third end of the J1 plug-in.

[0017] In an optional embodiment, the simulated blower circuit further includes a speed control module, wherein the G terminal of the speed control module is connected to the first terminal of the J1 plug-in; the D terminal of the speed control module is connected to the second terminal of the J1 module; and the S terminal of the speed control module is grounded.

[0018] In an optional embodiment, the analog high-side and low-side output circuit includes a third light-emitting diode, a J3 plug-in, a J12 plug-in, a fourth resistor, and a parallel resistor; the first end of the J3 plug-in is connected to the power supply circuit module; the second end of the J3 plug-in is connected to the positive terminal of the third light-emitting diode and one end of the parallel resistor through the fourth resistor; the first end of the J12 plug-in is connected to the negative terminal of the third light-emitting diode and the other end of the parallel resistor; the second end of the J12 plug-in is grounded.

[0019] In an optional embodiment, the analog drive motor circuit includes a J21 plug-in, an analog resistor, a second resistor, a third resistor, a fourth LED, and a fifth LED; one end of the analog resistor is connected to one end of the J21 plug-in and one end of the third resistor; the other end of the analog resistor is connected to the other end of the J21 plug-in and one end of the second resistor; the other end of the second resistor is connected to the positive terminal of the fourth LED; the other end of the third resistor is connected to the positive terminal of the fifth LED; and the negative terminals of both the fourth and fifth LEDs are grounded.

[0020] In an optional embodiment, the analog drive motor circuit further includes a first diode and a second diode; the cathode of the first diode is connected to the side of the second resistor closest to the fourth light-emitting diode; the cathode of the second diode is connected to the side of the third resistor closest to the fifth light-emitting diode; and the anodes of both the first diode and the second diode are grounded.

[0021] Due to the adoption of the above technical solution, this application has at least one of the following beneficial effects compared with the prior art:

[0022] 1. By using modules such as analog sensor circuits, analog drive motor circuits, analog high and low side output circuits, and analog blower circuits to replace the actual load equipment, the test configuration is simplified and the cost is reduced.

[0023] 2. The circuit design, consisting of a pure resistive circuit and LEDs, avoids the influence of capacitors or capacitive loads on the test results and also reduces the size of the equipment.

[0024] 3. A fuse is installed in the power supply circuit module, which can immediately cut off the power supply circuit when abnormal conditions such as overcurrent or overvoltage are detected, to prevent the fault from escalating and ensure the safety and reliability of the testing process.

[0025] 4. The technical solution includes a control unit to adjust the test conditions, which improves test efficiency. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] in:

[0028] Figure 1 A schematic diagram of the frame of an automotive electromagnetic compatibility test load box provided in an embodiment of this application;

[0029] Figure 2 A schematic diagram of the electromagnetic compatibility test circuit provided in an embodiment of this application;

[0030] Figure 3 A circuit diagram of an electromagnetic compatibility test circuit provided in an embodiment of this application;

[0031] Figure 4 A circuit diagram of an analog sensor circuit provided in an embodiment of this application;

[0032] Figure 5 A circuit diagram of a simulated blower circuit provided in an embodiment of this application;

[0033] Figure 6 A circuit diagram of an analog high-side and low-side output circuit provided in an embodiment of this application;

[0034] Figure 7This is a circuit diagram of an analog drive motor circuit provided in one embodiment of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0036] The terms "first," "second," etc., used in this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] Traditional EMC testing typically requires actual components such as blowers, motors, and numerous sensors. These devices are not only expensive to purchase, but also incur additional costs for maintenance and replacement. This application, however, replaces the actual load equipment with modules such as simulated sensor circuits, simulated drive motor circuits, and simulated blower circuits, significantly reducing testing costs. Figure 1-2 As shown, Figure 1 This is a schematic diagram of the frame of an automotive electromagnetic compatibility test load box provided in one embodiment of this application. Figure 2 This is a schematic diagram of the electromagnetic compatibility test circuit provided in one embodiment of this application. The load box includes:

[0039] Box;

[0040] The electromagnetic compatibility (EMC) test circuit is housed within a casing. It includes an analog sensor circuit, an analog drive motor circuit, an analog high / low side output circuit, an analog blower circuit, and a power supply circuit module.

[0041] Analog sensor circuits include voltage-type sensors and resistive sensors; voltage-type sensors or resistive sensors are selected for testing based on different testing requirements; when a stable or changing voltage signal from an analog signal source is needed to represent a certain physical quantity, a voltage-type sensor can be selected; for example, when testing the response of an air conditioner controller to changes in ambient temperature, a voltage-type sensor can be used to simulate the voltage output at different temperatures.

[0042] For situations where changes in resistance are used to represent changes in physical quantities, a resistive sensor is chosen. For example, when simulating the operation of an air flow meter, since its working principle is based on the change in resistance with airflow velocity, a resistive sensor is more suitable.

[0043] This system simulates different operating states of a motor by using a simulated drive motor circuit. By simulating different motor operating states, test scenarios can be quickly switched without actually replacing the physical motor or adjusting complex mechanical settings, greatly improving test efficiency and flexibility. It also avoids the high costs associated with using real motors and their supporting hardware for testing, including equipment procurement, maintenance, and wear and tear costs caused by frequent operation.

[0044] The simulation high-side and low-side output circuit simulates the high-side or low-side output function of the control unit to the load; by accurately simulating the high-side and low-side output conditions, the behavior of the control unit in actual operation can be more realistically reflected, ensuring that the test results are more accurate and reliable.

[0045] The system simulates the operation of a blower by simulating its circuitry; this avoids the costs of purchasing and maintaining a real blower, while also reducing additional expenses caused by physical equipment damage; all operations can be achieved through electrical connections, reducing complex mechanical installation steps and making the entire testing process simpler and faster; it simulates various operating states of the blower, including fault conditions, in a safe and controllable environment, avoiding the risks that may arise from directly operating high-power equipment and ensuring the safety of the testing process.

[0046] The power supply circuit module provides power to the analog sensor circuit, analog drive motor circuit, analog high and low side output circuit, and analog blower circuit. The design of the power supply circuit module ensures a stable power supply to all analog circuits, avoiding inaccurate testing due to power fluctuations and improving the reliability of test results. The centralized power supply scheme simplifies maintenance, requiring only attention to one main power supply point, reducing the complexity and potential fault points that may result from multiple power supply points.

[0047] It also includes a control unit, which adjusts the test conditions of the electromagnetic compatibility test circuit.

[0048] In summary, the load box in this embodiment includes a housing, an electromagnetic compatibility (EMC) test circuit, and a control unit. The control unit adjusts the test conditions of the EMC test circuit. The EMC test circuit is housed within the housing and includes an analog sensor circuit, an analog drive motor circuit, an analog high-side and low-side output circuit, an analog blower circuit, and a power supply module. The analog sensor circuit includes voltage-type sensors and resistance-type sensors. Voltage-type or resistance-type sensors are selected for testing based on different test requirements. The analog blower circuit simulates the operation of a blower. The power supply module provides power to the analog sensor circuit, analog drive motor circuit, analog high-side and low-side output circuit, and analog blower circuit. By replacing the actual load equipment with modules, the test configuration is simplified, and costs are reduced.

[0049] like Figure 3 As shown, Figure 3 This is a circuit diagram of an electromagnetic compatibility test circuit provided in an embodiment of this application. The power supply circuit module includes a fuse F1, a first light-emitting diode (LED1), and a first resistor R1. The fuse F1 is connected to the positive terminal of the first LED1. The negative terminal of the first LED1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded. The power supply circuit module also includes a battery terminal BATT and a first switch SW1. The battery terminal BATT is connected to the side of the fuse F1 away from the first LED1 through the first switch SW1. The voltage VCC between the first switch SW1 and the fuse F1 supplies power to the analog sensor circuit, the analog drive motor circuit, the analog high-side and low-side output circuit, and the analog blower circuit. The working principle of the power supply circuit module is described in detail below:

[0050] The power supply circuit module obtains electrical energy from the battery and controls the current flow through the first switch. When the first switch is closed, the voltage supplied by the battery passes through the first switch to the fuse; the fuse's function is to melt and break the current path in case of excessive current or a short circuit, thereby protecting the subsequent circuits from damage.

[0051] The current after passing through the fuse continues to flow to the positive terminal of the first LED. If the circuit is working properly and no overcurrent occurs, the current will pass through the first LED and cause it to light up, serving as a visual indication that the power supply is working properly.

[0052] The negative terminal of the first LED is then connected to one end of the first resistor, while the other end of the first resistor is grounded. This design not only helps limit the amount of current flowing through the first LED, preventing it from being damaged by overcurrent, but also forms a complete loop, allowing the current to travel from the battery back to ground.

[0053] At the node formed between the first switch and the fuse, a voltage divider effect occurs due to the presence of resistance (including the tiny resistance of the fuse itself). The voltage provided at this node is used to power the analog sensor circuit, the analog drive motor circuit, the analog high-side and low-side output circuit, and the analog blower circuit. When the first switch is closed, this voltage is sufficient to activate these analog circuits, enabling them to operate according to their predetermined functions, such as simulating different types of sensor responses and different operating states of the drive motor.

[0054] like Figure 4 As shown, Figure 4 This is a circuit diagram of an analog sensor circuit provided in an embodiment of this application. The analog sensor circuit includes a J10 plug-in, a J19 plug-in, and a J25 plug-in. The first terminal of the J10 plug-in is connected to the power supply circuit module. The second terminal of the J10 plug-in is connected to multiple interfaces of the J19 plug-in through multiple adjustable resistors. The second terminal of the J10 plug-in is connected to the first terminal of the J25 plug-in. The second terminal of the J25 plug-in is grounded. The working principle of the analog sensor circuit is described in detail below:

[0055] The first end of the J10 plug-in is connected to the power supply circuit module to ensure that the necessary power supply is provided for the entire analog sensor circuit.

[0056] The second end of the J10 plug-in is connected to multiple interfaces of the J19 plug-in via multiple adjustable resistors; each adjustable resistor represents a possible sensor input state.

[0057] When simulating voltage-type sensors, the voltage level between the J10 and J19 connectors can be changed by adjusting the corresponding adjustable resistor value, thereby simulating changes in the sensor output under different conditions. For example, the resistor can be adjusted to simulate voltage output differences caused by changes in physical quantities such as temperature and pressure.

[0058] The second end of the J10 plug is also directly connected to the first end of the J25 plug, while the second end of the J25 plug is grounded; this configuration allows for the operation of analog resistive sensors.

[0059] In this setup, current flows from the power supply circuit module through connector J10 to connector J25 and finally to ground. By selecting an appropriate resistance value or using a variable resistor, the resistance changes of a resistive sensor under different operating conditions can be simulated; for example, it can be used to simulate sensors such as air flow meters that rely on resistance changes for operation.

[0060] like Figure 5 As shown, Figure 5This is a circuit diagram of a simulated blower circuit provided in an embodiment of this application; the simulated blower circuit includes a second light-emitting diode LED2, a second resistor R2 and a third resistor R3, and a J1 plug-in; the second end of the J1 plug-in is connected to the negative terminal of the second light-emitting diode LED2 and one end of the second resistor R2; the other end of the second resistor R2 and the positive terminal of the second light-emitting diode LED2 are connected to one end of the third resistor R3; the other end of the third resistor R3 is connected to the third end of the J1 plug-in.

[0061] The simulated blower circuit also includes a speed control module. The G terminal of the speed control module is connected to the first terminal of the J1 plug-in; the D terminal of the speed control module is connected to the second terminal of the J1 module; and the S terminal of the speed control module is grounded.

[0062] When the power supply module provides power to the entire system, the current first flows to the J1 plug-in and follows the path described above, illuminating LED2 to indicate that the blower is at its lowest speed or in basic operating condition. By adjusting the speed control module, the voltage difference between the D and S terminals can be controlled, thus affecting the current intensity flowing through LED2. As the speed control module settings change, the brightness of LED2 will also change accordingly. Higher current will cause LED2 to be brighter, symbolizing that the blower is operating at a higher speed.

[0063] To test the system's response to potential blower malfunctions, you can disconnect or short-circuit certain key components (such as R2, R3, or LED2) and observe the system's reaction. This helps identify potential problems and make improvements.

[0064] like Figure 6 As shown, Figure 6 This is a circuit diagram of a simulated high-side and low-side output circuit provided in an embodiment of this application; the simulated high-side and low-side output circuit includes a third light-emitting diode LED3, a J3 plug-in, a J12 plug-in, a fourth resistor R4, and a parallel resistor R11; the first end of the J3 plug-in is connected to the power supply circuit module; the second end of the J3 plug-in is connected to the positive terminal of the third light-emitting diode LED3 and one end of the parallel resistor R11 through the fourth resistor R4; the first end of the J12 plug-in is connected to the negative terminal of the third light-emitting diode LED3 and the other end of the parallel resistor R11; the second end of the J12 plug-in is grounded.

[0065] When it is necessary to simulate ECU high-side control of the load, the operation is as follows:

[0066] Connect the product under test to the J3 plugin;

[0067] The load cell is shorted by the J12 connector (i.e., the first and second terminals of J12 are connected).

[0068] The current path at this time is: power supply circuit → first terminal of J3 plug-in → second terminal of J3 → R4 → LED3 positive terminal → LED3 negative terminal → first terminal of J12 plug-in → second terminal of J12 plug-in (grounded) → ground

[0069] In this state, LED3 being lit indicates that the load is in a "controlled conduction" state, simulating the load operation under the control of a high-side switch.

[0070] When it is necessary to simulate ECU low-side control of the load, the operation is as follows:

[0071] Connect the product under test to the J12 plugin;

[0072] Short-circuit J3 plug in the load cell (i.e., connect the first and second terminals of J3);

[0073] The current path at this time is: power supply circuit → first terminal of J3 plug-in → second terminal of J3 plug-in (short-circuited) → R4 → LED3 positive terminal → LED3 negative terminal → first terminal of J12 plug-in → second terminal of J12 plug-in (grounded) → ground

[0074] In this configuration, the control signal is emitted from the low side, which also lights up LED3, simulating the load working state under low-side drive.

[0075] like Figure 7 As shown, Figure 7 This is a circuit diagram of a simulated drive motor circuit provided in one embodiment of this application. The simulated drive motor circuit includes a J21 plug-in, a simulated resistor, a second resistor, a third resistor, a fourth LED, and a fifth LED. One end of the simulated resistor is connected to one end of the J21 plug-in and one end of the third resistor; the other end of the simulated resistor is connected to the other end of the J21 plug-in and one end of the second resistor; the other end of the second resistor is connected to the positive terminal of the fourth LED; the other end of the third resistor is connected to the positive terminal of the fifth LED; the negative terminals of both the fourth and fifth LEDs are grounded. The simulated motor has two states: forward and reverse rotation.

[0076] When current flows into the J21 plug-in, it passes through the analog resistor and then flows to the second or third resistor, lighting up the fourth or fifth LED respectively.

[0077] The fourth LED being lit indicates that the motor is rotating in the forward direction;

[0078] The fifth LED lighting up indicates that the motor is in reverse rotation.

[0079] If both LEDs are off, it may indicate that the motor is not powered or is in a faulty state.

[0080] The analog drive motor circuit also includes a first diode and a second diode; the cathode of the first diode is connected to the side of the second resistor closest to the fourth LED; the cathode of the second diode is connected to the side of the third resistor closest to the fifth LED; the anodes of both the first and second diodes are grounded; the function of the first diode D1 and the second diode D2 is to prevent reverse current backflow or crosstalk, and to ensure that the LEDs work independently in their respective channels; for example, when the fourth LED is turned on, the first diode prevents current from returning through the fifth LED circuit.

[0081] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0082] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0083] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0084] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An automotive electromagnetic compatibility test load box, characterized by, include: Box; Electromagnetic compatibility (EMC) testing circuit, housed within the enclosure, comprising: An analog sensor circuit, comprising voltage-type sensors and resistive sensors, is used to select either a voltage-type sensor or a resistive sensor for testing based on different testing requirements. A simulated drive motor circuit is used to simulate different operating states of a motor. A simulated high-side and low-side output circuit is used to simulate the high-side or low-side output function of the control unit on the load. A simulated blower circuit is used to simulate the operation of a blower. The power supply circuit module provides power to the analog sensor circuit, the analog drive motor circuit, the analog high and low side output circuit, and the analog blower circuit. The control unit adjusts the test conditions of the electromagnetic compatibility test circuit based on the control unit.

2. The automotive EMC test load box of claim 1, wherein, The power supply circuit module includes a fuse, a first light-emitting diode (LED), and a first resistor; the fuse is connected to the positive terminal of the first LED; the negative terminal of the first LED is connected to one end of the first resistor, and the other end of the first resistor is grounded.

3. The automotive EMC test load box of claim 2, wherein, The power supply circuit module includes a battery terminal and a first switch; the battery terminal is connected to the side of the fuse away from the first light-emitting diode through the first switch; the analog sensor circuit, the analog drive motor circuit, the analog high and low side output circuit and the analog blower circuit are powered based on the voltage division between the first switch and the fuse.

4. The automotive electromagnetic compatibility test load box according to claim 1, characterized in that, The analog sensor circuit includes a J10 plug-in, a J19 plug-in, and a J25 plug-in; the first end of the J10 plug-in is connected to the power supply circuit module; the second end of the J10 plug-in is connected to multiple interfaces of the J19 plug-in through multiple adjustable resistors; the second end of the J10 plug-in is connected to the first end of the J25 plug-in; and the second end of the J25 plug-in is grounded.

5. The automotive electromagnetic compatibility test load box according to claim 1, characterized in that, The simulated blower circuit includes a second light-emitting diode, a second resistor, a third resistor, and a J1 plug-in; the second end of the J1 plug-in is connected to the negative terminal of the second light-emitting diode and one end of the second resistor; the other end of the second resistor and the positive terminal of the second light-emitting diode are connected to one end of the third resistor; the other end of the third resistor is connected to the third end of the J1 plug-in.

6. The automotive electromagnetic compatibility test load box according to claim 5, characterized in that, The simulated blower circuit also includes a speed control module, the G terminal of which is connected to the first terminal of the J1 plug-in; the D terminal of which is connected to the second terminal of the J1 module; and the S terminal of which is grounded.

7. The automotive electromagnetic compatibility test load box according to claim 1, characterized in that, The analog high-low side output circuit includes a third LED, a J3 plug-in, a J12 plug-in, a fourth resistor, and a parallel resistor; the first end of the J3 plug-in is connected to the power supply circuit module; the second end of the J3 plug-in is connected to the positive terminal of the third LED and one end of the parallel resistor through the fourth resistor; the first end of the J12 plug-in is connected to the negative terminal of the third LED and the other end of the parallel resistor; the second end of the J12 plug-in is grounded.

8. The automotive electromagnetic compatibility test load box according to claim 1, characterized in that, The simulated drive motor circuit includes a J21 connector, a simulated resistor, a second resistor, a third resistor, a fourth LED, and a fifth LED. One end of the simulated resistor is connected to one end of the J21 connector and one end of the third resistor. The other end of the simulated resistor is connected to the other end of the J21 connector and one end of the second resistor. The other end of the second resistor is connected to the positive terminal of the fourth LED. The other end of the third resistor is connected to the positive terminal of the fifth LED. The negative terminals of both the fourth and fifth LEDs are grounded.

9. The automotive electromagnetic compatibility test load box according to claim 8, characterized in that, The analog drive motor circuit also includes a first diode and a second diode; the negative terminal of the first diode is connected to the side of the second resistor closest to the fourth light-emitting diode; the negative terminal of the second diode is connected to the side of the third resistor closest to the fifth light-emitting diode; the positive terminals of both the first diode and the second diode are grounded.

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