Nonlinear element characteristic measurement experiment instrument

Abstract

The utility model provides a nonlinear element characteristic measurement experiment instrument. The nonlinear element characteristic measurement experiment instrument comprises an experiment instrument panel, a state display module, a nonlinear element to-be-measured area, an AC / DC conversion power panel and a voltage measurement module are arranged on the experiment instrument panel; the AC-DC conversion power supply board at least comprises a power supply module and a circuit building module, and the power supply module is connected with the nonlinear test element and is also connected with the circuit building module, the voltage measurement module and the external oscilloscope in sequence; the circuit building module comprises a first connection area, a second connection area and a third connection area; the voltage measurement module comprises an A / D conversion chip and a voltage measurement calibration circuit. The voltage measurement calibration circuit is composed of a reference voltage source, an adjustable potentiometer RV1 and a voltage division network with a preset voltage division ratio. The nonlinear element characteristic measurement experiment instrument is simple in structure, convenient to operate and accurate in measurement, the teaching quality of experiments is improved, and the failure rate and the maintenance time in the experiments are reduced at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of measuring experimental instruments, in particular to a nonlinear element characteristic measuring experimental instrument. Background Art

[0002] Electricity is a branch of physics. Designed electrical experiments can effectively test students' experimental skills and creative thinking ability. The experiment of "measuring the volt-ampere characteristics of nonlinear components" is widely taught in many universities. However, the experimental operation process is cumbersome and involves many experimental instruments, which is not conducive to student operation. The error of the measurement results is also often large, making it difficult to obtain an accurate voltage change waveform based on the experimental parameters of the measurement results. In addition, if the instrument fails during classroom teaching, it will cause great trouble. It is necessary to make an appointment with after-sales service for repair, which often takes a long time to troubleshoot. This is a worry for most experimental teachers. Utility Model Content

[0003] In view of this, the purpose of the utility model is to provide a nonlinear component characteristic measurement experiment instrument. The present application flexibly connects the nonlinear component to be tested of the experiment instrument with an AC / DC conversion power supply board divided into three test connection areas, so that test personnel can obtain experimental parameters to observe and record the effects of different capacitors on the rectified voltage waveform. When an instrument fails, it can be located promptly and quickly for maintenance. At the same time, a voltage measurement calibration circuit is designed in the voltage measurement module to improve the accuracy of the measurement results of the experiment instrument and the reliability of the experimental parameters.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A nonlinear element characteristic measurement experiment instrument comprises an experiment instrument panel; at least a state display module, a nonlinear element test area, an AC / DC conversion power supply board and a voltage measurement module are arranged on the experiment instrument panel. The state display module comprises at least a plurality of running lights, and any of the running lights is connected to a nonlinear test element in the nonlinear element test area in a one-to-one correspondence.

[0006] The AC / DC conversion power board at least includes a power module and a circuit construction module, one end of the power module is connected to the nonlinear test element, the other end of the power module is connected to one end of the circuit construction module, the other end of the circuit construction module is connected to one end of the voltage measurement module, and the other end of the voltage measurement module is connected to an external oscilloscope; wherein the circuit construction module includes a first connection area, a second connection area and a third connection area.

[0007] The voltage measurement module at least includes an A / D conversion chip and a voltage measurement calibration circuit; the voltage measurement calibration circuit is at least composed of a reference voltage source, an adjustable potentiometer RV1 and a voltage divider network with a preset voltage divider ratio; wherein one end of the reference voltage source is connected to one end of the adjustable potentiometer RV1, the other end of the adjustable potentiometer RV1 is connected to the A / D conversion chip, and the voltage divider network with a preset voltage divider ratio is connected to the A / D conversion chip.

[0008] In the utility model, the status display module further includes a first display screen, a register, a first driver, a display module main controller and a second driver.

[0009] Furthermore, one end of the register is connected to the first display screen, and the other end of the register is connected to the display module main controller; the display module main controller is connected in parallel with the multiple flowing lights one by one through the first driver and the second driver respectively; wherein any of the flowing lights is also connected in series with a resistor.

[0010] In the utility model, the nonlinear element test area is composed of a forward volt-ampere characteristic test area and a reverse volt-ampere characteristic test area; the nonlinear element test area also includes a current measurement module; in the forward volt-ampere characteristic test area, the negative terminal of the nonlinear test element is connected to the current measurement module; in the reverse volt-ampere characteristic test area, the positive terminal of the nonlinear test element is connected to the current measurement module.

[0011] In the present invention, the first connection region at least includes a first nonlinear element, a second nonlinear element, a third nonlinear element and a fourth nonlinear element.

[0012] Among them, the positive electrode of nonlinear element one is connected to the negative electrode of nonlinear element three, the positive electrode of nonlinear element two is connected to the negative electrode of nonlinear element four, the negative electrode of nonlinear element one is connected to the negative electrode of nonlinear element two, and the positive electrode of nonlinear element three is connected to the positive electrode of nonlinear element four; one end of the power module is connected between the positive electrode of nonlinear element one and the negative electrode of nonlinear element three, and the other end of the power module is connected between the positive electrode of nonlinear element two and the negative electrode of nonlinear element four.

[0013] In the present invention, the second connection area at least includes a preset capacitor group and an analog switch SW1; one end of the preset capacitor group is connected to one end of the analog switch SW1, and the other end of the preset capacitor group is grounded; wherein the preset capacitor includes a plurality of capacitors connected in parallel to each other; the other end of the analog switch SW1 is connected to the third connection area.

[0014] The third connection region at least includes a resistor R1, a resistor R2, a resistor R3, a voltage regulator tube D1 and a voltage regulator tube D2.

[0015] Among them, one end of the resistor R1 is connected to the other end of the analog switch SW1, the other end of the resistor R1 is connected to the negative electrode of the Zener diode D1, the other end of the resistor R1 is also connected to one end of the resistor R2, the other end of the resistor R2 is connected to the negative electrode of the Zener diode D2, the other end of the resistor R2 is also connected to one end of the resistor R3, the other end of the resistor R3 is connected to the voltage measurement module, and after the positive electrode of the Zener diode D1 is connected to the positive electrode of the Zener diode D2, it is also connected to the voltage measurement module.

[0016] In the utility model, the voltage measurement module also includes a timing circuit, a negative voltage generator, a third driver, a fourth driver and a second display; the timing circuit and the negative voltage generator are respectively connected to the A / D conversion chip, and the A / D conversion chip is also connected to the second display through the third driver and the fourth driver.

[0017] In the present invention, the voltage measurement calibration circuit further includes a capacitor C1, a resistor R4 and a voltage stabilizing diode D3.

[0018] The second pin of the reference voltage chip in the reference voltage source is connected to the cathode of the Zener diode D3, and the cathode of the Zener diode D3 is also respectively connected to one end of the capacitor C1, one end of the resistor R4, and one end pin of the adjustable potentiometer RV1, and the moving pin of the adjustable potentiometer RV1 is connected to the REF pin of the A / D conversion chip.

[0019] The anode of the voltage zener diode D3 is respectively connected to the 1st pin of the reference voltage chip, the 3rd pin of the reference voltage chip, the other end of the capacitor C1, and the other end pin of the adjustable potentiometer RV1. The other end pin of the adjustable potentiometer RV1 is connected to the ACOM pin of the A / D conversion chip.

[0020] Among them, a preset value of base regulated voltage is provided at the second pin of the reference voltage chip in the reference voltage source. The preset value of the base regulated voltage is passed through the adjustable potentiometer RV1 to obtain the reference source of the target value, and is input to the A / D conversion chip from the REF pin of the A / D conversion chip.

[0021] In the present invention, the voltage divider network with a preset voltage divider ratio at least includes: an analog switch SW2, a resistor R5 and a resistor R6; and further includes a resistor R7 and a capacitor C2 between the voltage divider network with a preset voltage divider ratio and the A / D conversion chip.

[0022] Among them, the first connection end of the analog switch SW2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the INLO pin of the A / D conversion chip; the second connection end of the analog switch SW2 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to the INHI pin of the A / D conversion chip; between the other end of the resistor R6 and the other end of the resistor R7, the two ends of the capacitor C2 are respectively connected.

[0023] Compared with the prior art, the beneficial effects of the utility model are:

[0024] The utility model proposes a nonlinear component characteristic measurement experiment instrument. By dividing the nonlinear component to be tested and the AC-DC conversion power supply board into three test connection areas, the tester can more conveniently build different circuits, observe and record the influence of different components on the rectified voltage waveform, thereby simplifying the experimental operation process. When the instrument fails, due to the division of the circuit construction module, the fault area can be quickly located and repaired. This design reduces the time for fault diagnosis and repair and improves teaching efficiency. In addition, the application designs a voltage measurement calibration circuit in the voltage measurement module, which is composed of a reference voltage source, an adjustable potentiometer RV1 and a voltage divider network with a preset voltage divider ratio, which can provide an accurate voltage input reference source and allow calibration to improve the accuracy of the experimental instrument measurement results. The design of the AC-DC conversion power supply board allows different circuits to be flexibly built to meet different experimental needs, and can also be used for teaching demonstrations to improve students' learning interest and participation. The application aims to improve the teaching quality of electrical design experiments and students' experimental skills by designing a nonlinear component characteristic measurement experiment instrument with simple structure, convenient operation and accurate measurement, while reducing the failure rate and maintenance time in the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a nonlinear element characteristic measurement experimental instrument according to a preferred embodiment of the utility model.

[0026] Figure 2 It is a circuit principle diagram of the status display module of the preferred embodiment of the utility model.

[0027] Figure 3 It is a circuit schematic diagram of the forward volt-ampere characteristic test of the preferred embodiment of the utility model.

[0028] Figure 4 It is a circuit schematic diagram of the reverse volt-ampere characteristic test of the preferred embodiment of the utility model.

[0029] Figure 5 It is a circuit structure principle diagram of an AC / DC conversion power supply board according to a preferred embodiment of the utility model.

[0030] Figure 6 It is a circuit structure principle diagram of the voltage measurement module of the preferred embodiment of the utility model.

[0031] Figure 7 It is a circuit structure principle diagram of a reference voltage source of a preferred embodiment of the utility model.

[0032] Figure 8 It is a circuit structure principle diagram of a voltage divider network with a preset voltage divider ratio in a preferred embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the accompanying drawings. The accompanying drawings provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0034] Embodiment 1:

[0035] Please refer to Figure 1 In a preferred embodiment, a nonlinear element characteristic measurement experiment instrument includes an experiment instrument panel; at least a status display module, a nonlinear element test area, an AC / DC conversion power supply board and a voltage measurement module are arranged on the experiment instrument panel.

[0036] It should be noted that the experimental instrument proposed in this application is mainly used for testing experiments on crystal diode characteristics, and is intended to allow testers to understand the characteristics and usage skills of diodes in experiments. Among them, diodes are subdivided into many categories based on their application functions, such as detector diodes, rectifier diodes, voltage regulator diodes, switching diodes, light-emitting diodes, etc. Different types of diodes have different characteristic parameters, so their characteristic curves are also different. The waveform diagram generated by the experimental parameters can be used to observe the changes in the waveform curves of different diodes or the same diode under different test environments, so that testers can more intuitively and accurately understand the characteristics of semiconductor devices such as diodes.

[0037] In other embodiments, the experimental instrument of the present application may also combine diode and transistor experiments, and then introduce or develop field effect transistor characteristic measurements to form modular measurements, which are not limited thereto.

[0038] Wherein, the state display module at least includes a plurality of running lights, and any of the running lights is connected in a one-to-one correspondence with a nonlinear test element in the nonlinear element to-be-tested area.

[0039] It should be noted that the status display module can be an LED display screen or an LCD display screen, etc., and the present utility model preferably uses an LED display screen.

[0040] Furthermore, the status display module also includes a first display screen, a register, a first driver, a display module main controller and a second driver.

[0041] Among them, one end of the register is connected to the first display screen, and the other end of the register is connected to the display module main controller; the display module main controller is connected in parallel with the multiple running lights through the first driver and the second driver respectively; wherein any of the running lights is also connected in series with a resistor.

[0042] As attached Figure 2 As shown, in this embodiment, there are 16 running lights connected in series with 16 resistors of the same resistance value, and the running lights use light-emitting diodes; the first display screen is represented by A1 in the figure, and A1 can use an LED liquid crystal screen that displays characters; for example, for LCD, models such as Nokia 5110 (suitable for small-size display screens) and HD44780 compatible LCD (suitable for character and graphic display) can be considered. In addition, if it is an LED display screen, models such as MAX7219 or MAX7221 (LED drivers for driving multiple LEDs) can be considered, but are not limited to this.

[0043] The register is represented by U4 in the figure. U4 can use a register of model 74HC595. The register is connected to the first display A1 through the RN1 connector. 74HC595 is a shift register for serial input and parallel output; the models of the devices used by the first driver U2 and the second driver U3 need to be the same or compatible to maintain the consistency of the system. In this embodiment, the same ULN2803A is preferably used; the display module main controller U1 can use the ATMEGA8 model, but it is not limited to this.

[0044] It should be noted that the LED display board is connected to a +5V power supply, and the changes of the running lights are observed after power is turned on. Because the running lights are connected one-to-one with the nonlinear test elements, an instant feedback mechanism is provided. Users can judge whether the nonlinear elements are working properly and the operation of the circuit by observing the status of the running lights.

[0045] In addition, the display module main controller is connected in parallel with a plurality of running lights through the first driver and the second driver to realize the control of the running lights. This control method can be used to realize a specific display mode, such as indicating different experimental steps or states.

[0046] In this embodiment, the use of registers and shift registers (such as 74HC595) simplifies the circuit design, making it simple and easy to implement to control multiple running lights. Since the number of running lights can be increased or decreased as needed, the status display module has good scalability. This means that it is easy to add more test components to the experimenter or expand the experimental functions.

[0047] In summary, by observing the changes in the running lights, users can quickly identify faults or abnormalities in the circuit, which is very useful for fault diagnosis and maintenance in experiments. The design of the status display module not only improves the functionality of the experimental instrument, but also provides students with a practical opportunity to learn electronic principles and circuit design.

[0048] In the present invention, the nonlinear element to be tested region is composed of a forward volt-ampere characteristic test region and a reverse volt-ampere characteristic test region; Figure 3 and attached Figure 4 As shown, they are respectively the circuit design principle diagrams of the forward volt-ampere characteristic test and the reverse volt-ampere characteristic test of the present application. Wherein, the nonlinear element to be tested area also includes a current measurement module; in the forward volt-ampere characteristic test area, the negative terminal of the nonlinear test element is connected to the current measurement module; in the reverse volt-ampere characteristic test area, the positive terminal of the nonlinear test element is connected to the current measurement module.

[0049] It should be noted that the forward and reverse connection ports can be used to switch the forward volt-ampere characteristic test mode and the reverse volt-ampere characteristic test mode on the panel of this experimental instrument. Figure 3 In the forward volt-ampere characteristic measurement circuit shown, one end of the power supply is connected to one end of the switch K, the other end of the switch K is connected to the first end of the sliding rheostat, the other end of the sliding rheostat is connected to the second end of the sliding rheostat, the third end of the sliding rheostat is connected to one end of the voltmeter, the anode (or corresponding positive pole) of the nonlinear element (such as a diode, transistor, etc.) is connected to the first end of the sliding rheostat, and the cathode (or corresponding negative pole) of the nonlinear element is connected to the other end of the voltmeter. Among them, the second end of the sliding rheostat is first connected to one end of the current measurement module and then connected to the other end of the voltmeter. Its working principle is:

[0050] When switch K is closed, the power supply provides voltage to the nonlinear element through the sliding rheostat; the sliding rheostat allows the user to adjust the current passing through the nonlinear element, thereby changing the voltage across it; the voltmeter measures and displays the voltage across the nonlinear element and draws a volt-ampere characteristic curve; by changing the resistance value of the sliding rheostat, the voltage response of the nonlinear element under different currents can be observed, thereby studying its forward volt-ampere characteristics.

[0051] In the attached Figure 4In the reverse volt-ampere characteristic measurement circuit shown, one end of the power supply is connected to one end of the switch K, the other end of the switch K is connected to the first end of the sliding rheostat, the other end of the sliding rheostat is connected to the second end of the sliding rheostat, the third end of the sliding rheostat is connected to one end of the voltmeter, the cathode (or corresponding negative pole) of the nonlinear element (such as a diode, a transistor, etc.) is connected to the first end of the sliding rheostat, and the anode (or corresponding positive pole) of the nonlinear element is connected to the other end of the voltmeter. Among them, the second end of the sliding rheostat is first connected to the other end of the voltmeter, and then connected to one end of the current measurement module. Its working principle is:

[0052] When switch K is closed, the power supply provides reverse bias voltage to the nonlinear element through the sliding rheostat; the sliding rheostat allows the user to adjust the current through the nonlinear element, thereby changing the voltage across it; the voltmeter measures and displays the voltage across the nonlinear element, and plots the volt-ampere characteristic curve; by changing the resistance of the sliding rheostat, the voltage response of the nonlinear element under different currents can be observed, thereby studying its reverse volt-ampere characteristics. The current measurement module measures the current through the nonlinear element, and is used together with the voltmeter reading to analyze the characteristics of the nonlinear element.

[0053] Preferably, for example, a detector diode of model 2AP9 is tested for forward and reverse volt-ampere characteristics, wherein the forward volt-ampere characteristics: maximum forward current I≤20mA, voltage across the diode V≤1.3V, and the number of experimental points is not less than 15; the reverse volt-ampere characteristics: reverse voltage V≤20V, maximum reverse current I<50uA, and the number of experimental points is not less than 15. The experimental parameters are shown in the following table:

[0054] Serial number 1 2 3 4 5 6 7 8 9 Current mA 0.0+ 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 Voltage V 0.1916 0.2278 0.2453 0.2575 0.2645 0.2710 0.2759 0.2805 0.2838 Serial number 10 11 12 13 14 15 16 17 18 Current mA 3.6 4.0 6.0 8.0 10. 12.0 14.0 16.0 18.0 Voltage V 0.2872 0.2894 0.3023 0.3120 0.3195 0.3255 0.3311 0.3364 0.3408

[0055] Among them, the forward volt-ampere characteristic test: current range 20mA, power supply voltage +5V, voltmeter selected "forward"; reverse volt-ampere characteristic test: current range 50uA, power supply voltage +20V, voltmeter selected "reverse". The maximum voltage is adjusted to 19.715V, and there is almost no reverse current.

[0056] For example, to test the rectifier diode of model 1N4004, its forward volt-ampere characteristic is: the maximum forward current I≤20mA, the voltage across the diode V≤1V, and the number of experimental points is not less than 15; reverse volt-ampere characteristic: adjust the reverse voltage value so that its maximum is close to 20V, and observe the change of the current value of the microammeter.

[0057] Serial number 1 2 3 4 5 6 7 8 9 Current mA 0.0+ 0.4 0.8 1.2 1.6 2.0 2.4 3.2 3.6 Voltage V 0.4862 0.5576 0.5899 0.6080 0.6222 0.6316 0.6398 0.6521 0.6571 Serial number 10 11 12 13 14 15 16 17 18 Current mA 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 Voltage V 0.6617 0.6793 0.6915 0.7012 0.7083 0.7144 0.7204 0.7250 0.7294

[0058] Among them, the forward volt-ampere characteristic test: current range 20mA, power supply voltage +5V, voltmeter selected "forward"; reverse volt-ampere characteristic test: current range 50uA, power supply voltage +20V, voltmeter selected "reverse". The maximum voltage is adjusted to 19.736V, and the reverse current is zero, which is not limited to this.

[0059] In this embodiment, the AC / DC conversion power board includes at least a power module and a circuit construction module, one end of the power module is connected to the nonlinear test element, the other end of the power module is connected to one end of the circuit construction module, the other end of the circuit construction module is connected to one end of the voltage measurement module, and the other end of the voltage measurement module is connected to an external oscilloscope.

[0060] As attached Figure 5 As shown, the circuit building module includes a first connection area, a second connection area and a third connection area.

[0061] It should be noted that the power module can be a linear power supply, which usually uses a linear regulator (such as LM7805, LM317, etc.) to provide a stable DC voltage. The switching power supply achieves efficient power conversion through switching elements (such as MOSFET or IGBT) and control circuits.

[0062] Furthermore, in the present invention, the first connection region at least includes a nonlinear element 1, a nonlinear element 2, a nonlinear element 3 and a nonlinear element 4.

[0063] Preferably, the nonlinear element 1, the nonlinear element 2, the nonlinear element 3 and the nonlinear element 4 can all use rectifier diodes as test elements. In other embodiments, the first connection region can also include a half-wave rectifier of a single diode or a full-wave rectifier of two diodes, or a bridge rectifier circuit of four diodes, a single diode such as 1N4007, or a bidirectional rectifier diode such as 1N5408. In the drawings of this embodiment, preferably there are four rectifier diodes, namely D11, D12, D13 and D14, but are not limited thereto.

[0064] Among them, the positive electrode of nonlinear element one is connected to the negative electrode of nonlinear element three, the positive electrode of nonlinear element two is connected to the negative electrode of nonlinear element four, the negative electrode of nonlinear element one is connected to the negative electrode of nonlinear element two, and the positive electrode of nonlinear element three is connected to the positive electrode of nonlinear element four; one end of the power module is connected between the positive electrode of nonlinear element one and the negative electrode of nonlinear element three, and the other end of the power module is connected between the positive electrode of nonlinear element two and the negative electrode of nonlinear element four.

[0065] It should be noted that the power module provides an AC signal, which can be a sine wave, square wave or other waveform. The rectification process is:

[0066] When the AC signal passes through nonlinear elements one and three, under forward bias conditions, the diode is turned on, converting the AC signal into a pulsed DC signal; when the AC signal passes through nonlinear elements two and four, also under forward bias conditions, the diode is turned on, converting the AC signal into a pulsed DC signal.

[0067] The rectification effect is observed as follows: by observing the rectification waveforms under different diode combinations through an oscilloscope, the performance differences of different rectification circuits can be analyzed.

[0068] Component characteristic analysis: By observing the rectification waveforms of different diodes, the characteristics of each diode can be analyzed, such as the on-state voltage, forward current capacity, etc.

[0069] Circuit parameter adjustment: By changing the circuit parameters (such as the type of diode, frequency and amplitude of the power supply, etc.), the influence of these parameters on the rectification effect can be studied.

[0070] In other embodiments, this design can also be used for teaching demonstrations to help students understand the working principle and design method of the rectifier circuit. The design of the first connection area provides flexible circuit construction options, making the experimental operation more convenient, and also facilitates the tester to perform experimental operation and understanding.

[0071] In summary, the design of the first connection area provides users with a flexible rectifier circuit test platform, allowing users to observe and analyze the performance of different rectifier circuits, and can also be used for teaching demonstrations and experimental operations.

[0072] In the present invention, the second connection area at least includes a preset capacitor group and an analog switch SW1; one end of the preset capacitor group is connected to one end of the analog switch SW1, and the other end of the preset capacitor group is grounded; wherein the preset capacitor includes a plurality of capacitors connected in parallel to each other; the other end of the analog switch SW1 is connected to the third connection area.

[0073] Preferably, in the drawings of this embodiment, there may be three capacitors, capacitor C11: 1uF, capacitor C12: 10uF, capacitor C13: 100uF, but this is not limited to this.

[0074] In the design of the second connection area, the combination of the preset capacitor group and the analog switch SW1 provides the function of filtering and tuning the rectifier circuit. It should be noted that the capacitance values ​​of the multiple capacitors connected in parallel are different, and these capacitors can be fixed capacitors or adjustable capacitors, which are not limited thereto.

[0075] In this embodiment, the filtering effect is observed to be:

[0076] By controlling the preset capacitor group and analog switch SW1, the effect of different capacitance values ​​on the rectified waveform can be observed. A larger capacitance value will produce a smoother waveform, which is suitable for filtering low-frequency signals; a smaller capacitance value will produce a sharper waveform, which is suitable for filtering high-frequency signals.

[0077] The circuit parameters are adjusted as follows:

[0078] By changing the capacitance value of the preset capacitor group, the influence of these parameters on the filtering effect can be studied. The control of analog switch SW1 allows the user to quickly switch between different capacitor combinations for comparison and analysis.

[0079] In addition, in this embodiment, the analog switch SW1 controls the connection and disconnection of each capacitor of the preset capacitor group. Through the control of the analog switch SW1, the tester can select different capacitor combinations to change the filtering characteristics of the rectified output signal. For example, different time constants can be obtained by selecting different capacitor values ​​or combinations, which in turn affects the cutoff frequency of the filter. The analog switch SW1 allows the user to quickly switch different capacitor combinations, so that the effects of different filters can be quickly compared, which is convenient for experiments and teaching demonstrations.

[0080] The analog switch SW1 can be used to prevent the circuit from being damaged when it is not ready. For example, before the power supply is stable, the capacitor bank can be disconnected to prevent the voltage on the capacitor bank from being too high. In other embodiments, the analog switch SW1 can also be used as an isolation element to protect the analog signal from interference while allowing switching under different test conditions.

[0081] In summary, controlling the connection of the capacitor bank by analog switch SW1 can help users diagnose faults in the circuit. For example, if the filter performance does not meet expectations, you can quickly check whether the capacitor bank is connected correctly. Analog switch SW1 provides flexible operability, making experiments more convenient, and you can quickly change experimental conditions and conduct different experimental tests.

[0082] The design of the second connection area provides flexible filter circuit construction options, making the experimental operation more convenient and easy for students to operate and understand the experiment. By observing the changes in the rectified waveform, the performance of the circuit can be analyzed, such as response speed, stability, etc.

[0083] The third connection region at least includes a resistor R1, a resistor R2, a resistor R3, a voltage regulator tube D1 and a voltage regulator tube D2.

[0084] Among them, one end of the resistor R1 is connected to the other end of the analog switch SW1, the other end of the resistor R1 is connected to the negative electrode of the Zener diode D1, the other end of the resistor R1 is also connected to one end of the resistor R2, the other end of the resistor R2 is connected to the negative electrode of the Zener diode D2, the other end of the resistor R2 is also connected to one end of the resistor R3, the other end of the resistor R3 is connected to the voltage measurement module, and after the positive electrode of the Zener diode D1 is connected to the positive electrode of the Zener diode D2, it is also connected to the voltage measurement module.

[0085] It should be noted that in the attached Figure 5 In the embodiment, the third connection area may further include two light emitting diodes for displaying a working status, but is not limited thereto.

[0086] In the design of the third connection area, the combination of resistors R1, R2, R3, and voltage regulator tubes D1 and D2 provides the function of further adjusting and protecting the output of the rectifier circuit. Among them, resistors R1, R2, and R3 are used to divide the voltage and adjust the output voltage of the circuit. Voltage regulator tubes D1 and D2 are used to provide overvoltage protection to prevent the output voltage of the rectifier circuit from being too high and damaging the subsequent circuits or components. Through the voltage division effect of resistors R1, R2, and R3, the voltage value of the rectifier circuit output can be adjusted. Different resistor combinations can produce different output voltages, which is convenient for users to conduct experiments and analysis. Voltage regulator tubes D1 and D2 provide overvoltage protection to prevent the output voltage from being too high and protect the subsequent circuits and components. The voltage regulator tube is turned on when the output voltage exceeds its breakdown voltage, thereby limiting the output voltage.

[0087] The third connection area can be used to analyze the performance of the circuit, such as stability, response speed, etc., by observing the changes in the output voltage. It can also help testers understand the output regulation and protection mechanism of the circuit. The design of the third connection area provides flexible output regulation options, making the experimental operation more convenient, and also making it easier for students to operate and understand the experiment.

[0088] In summary, the design of the third connection area provides users with a flexible circuit output adjustment and protection platform, allowing users to observe and analyze the performance of different output adjustment circuits, and can also be used for teaching demonstrations and experimental operations.

[0089] The voltage measurement module at least includes an A / D conversion chip and a voltage measurement calibration circuit; the voltage measurement calibration circuit is at least composed of a reference voltage source, an adjustable potentiometer RV1 and a voltage divider network with a preset voltage divider ratio; wherein one end of the reference voltage source is connected to one end of the adjustable potentiometer RV1, the other end of the adjustable potentiometer RV1 is connected to the A / D conversion chip, and the voltage divider network with a preset voltage divider ratio is connected to the A / D conversion chip.

[0090] As attached Figure 6As shown, the voltage measurement module also includes a timing circuit, a negative voltage generator, a third driver, a fourth driver and a second display; the timing circuit and the negative voltage generator are respectively connected to the A / D conversion chip, and the A / D conversion chip is also connected to the second display through the third driver and the fourth driver.

[0091] It should be noted that the output voltage pin of the negative voltage generator is connected to the V- pin of the A / D conversion chip; Figure 5 As shown, the signal output pin of the time base circuit is connected to the clock input pin of the A / D conversion chip.

[0092] Preferably, in this embodiment, the negative voltage generator may use a chip of model ICL7660, and the time base circuit may use a time base chip of model 555, but the invention is not limited thereto. The clock input pin of the A / D conversion chip is represented by CLKIN.

[0093] It should be noted that the ICL7660 chip is a negative voltage generator that can convert positive voltage into negative voltage and is usually used to provide negative power for analog circuits. The role of the negative voltage generator is to provide a stable negative voltage reference for the A / D conversion chip, which is essential to ensure the accuracy and linearity of the A / D conversion. By connecting the output voltage pin of the negative voltage generator to the V- pin of the A / D conversion chip, the required negative voltage reference can be provided to the A / D conversion chip, thereby improving the measurement accuracy. The ICL7660 chip has a built-in protection circuit that can provide protection in the event of overvoltage or short circuit, ensuring the safety and stability of the circuit.

[0094] The 555 time base chip is a multi-purpose integrated circuit that can generate a stable square wave, sine wave or other waveform output according to the input signal. The function of the time base circuit is to provide a clock signal for the A / D conversion chip, which is the basis for analog-to-digital conversion. By connecting the signal output pin of the time base circuit to the clock input pin of the A / D conversion chip, it can ensure that the A / D conversion chip samples and converts at a stable clock frequency. The 555 time base chip has a stable oscillation characteristic and can maintain a stable clock frequency under different power supply voltage and temperature conditions, thereby ensuring the accuracy and repeatability of the A / D conversion.

[0095] In the present invention, the voltage measurement calibration circuit further includes a capacitor C1, a resistor R4 and a voltage stabilizing diode D3.

[0096] As attached Figure 7As shown, the second pin of the reference voltage chip in the reference voltage source is connected to the cathode of the Zener diode D3, and the cathode of the Zener diode D3 is also respectively connected to one end of the capacitor C1, one end of the resistor R4, and one end pin of the adjustable potentiometer RV1, and the moving pin of the adjustable potentiometer RV1 is connected to the REF pin of the A / D conversion chip.

[0097] The anode of the voltage zener diode D3 is respectively connected to the 1st pin of the reference voltage chip, the 3rd pin of the reference voltage chip, the other end of the capacitor C1, and the other end pin of the adjustable potentiometer RV1. The other end pin of the adjustable potentiometer RV1 is connected to the ACOM pin of the A / D conversion chip.

[0098] Among them, a preset value of base regulated voltage is provided at the second pin of the reference voltage chip in the reference voltage source. The preset value of the base regulated voltage is passed through the adjustable potentiometer RV1 to obtain the reference source of the target value, and is input to the A / D conversion chip from the REF pin of the A / D conversion chip.

[0099] Preferably, in this embodiment, the preset base stabilizing voltage may be 1.24V, and after being adjusted by the adjustable potentiometer RV1, an accurate reference source voltage of a target value of 1V is obtained, but the present invention is not limited thereto.

[0100] Preferably, the reference voltage chip may be a LM385 chip, but is not limited thereto.

[0101] As attached Figure 8 As shown, in the present invention, the voltage divider network with a preset voltage divider ratio includes at least: an analog switch SW2, a resistor R5 and a resistor R6; and a resistor R7 and a capacitor C2 are also included between the voltage divider network with a preset voltage divider ratio and the A / D conversion chip.

[0102] Among them, the first connection end of the analog switch SW2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the INLO pin of the A / D conversion chip; the second connection end of the analog switch SW2 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to the INHI pin of the A / D conversion chip; between the other end of the resistor R6 and the other end of the resistor R7, the two ends of the capacitor C2 are respectively connected.

[0103] It should be noted that, in the embodiment of the present application, a reference voltage of a preset value is input to the reference voltage source, and the reference voltage of the preset value is adjusted by the adjustable potentiometer RV1 to obtain a reference source of a target value. The movable pin of the adjustable potentiometer RV1 is connected to the REF pin of the A / D conversion chip, allowing the A / D conversion chip to receive the adjusted reference voltage.

[0104] The voltage divider network with a preset voltage divider ratio includes an analog switch SW2, a resistor R5, and a resistor R6. The analog switch SW2 is used to select the input of the voltage divider network, and the input voltage is divided to different voltage levels according to the voltage divider formed by resistors R5 and R6. Specifically, if the external measurement voltage is less than 2V, it will be directly input to resistor R7. This is because when the voltage is lower than 2V, the analog switch will directly flow the current to resistor R7 without passing through the voltage divider network of resistors R5 and R6.

[0105] If the external measured voltage is greater than 2V, it will be connected to the voltage divider network of resistors R5 and R6 through the analog switch SW2. Preferably, the preset voltage divider ratio can be 9:1, which means that the voltage will be input at a ratio of one tenth after passing through the voltage divider network to achieve the voltage adjustment purpose of the present application. The output of the voltage divider network is connected to the INLO and INHI pins of the A / D conversion chip, which are used to receive signals of different voltage levels.

[0106] Furthermore, the analog switch SW2 may be an electronic switch, such as a transistor or a field effect transistor, which receives a control signal to determine whether to connect the voltage path to the voltage divider network of the resistors R5 and R6. If the control signal is at a high level, the first connection terminal of the analog switch SW2 is turned on, and the voltage will pass through the voltage divider network; if the control signal is at a low level, the second connection terminal of the analog switch SW2 is turned on, and the voltage will flow directly to the resistor R7.

[0107] In summary, the analog switch SW2 can identify and control the switch state by receiving the control signal, thereby determining whether the voltage passes through the resistor divider network.

[0108] The A / D conversion chip converts the received analog signal into a digital signal. The converted digital signal can be used for voltage measurement and calibration. Capacitor C1 and resistor R4 together with Zener diode D3 can be used to filter out noise or stabilize the reference voltage source. Zener diode D3 provides overvoltage protection to ensure that the reference voltage source and voltage divider network will not be damaged due to excessive external voltage.

[0109] In this embodiment, by adjusting the reference voltage source through the adjustable potentiometer RV1, an accurate reference voltage can be obtained, thereby improving the accuracy of voltage measurement. By selecting different voltage divider network inputs through the analog switch SW2, it can adapt to the measurement requirements of different voltage levels. The voltage zener diode D3 provides overvoltage protection to protect the circuit from external voltage fluctuations. The A / D conversion chip converts the analog signal into a digital signal for digital processing and analysis. The implementation process of the voltage measurement calibration circuit is to achieve high-precision and flexible voltage measurement by adjusting the reference voltage source and the voltage divider network, and using the A / D conversion chip for digital processing.

[0110] In summary, the embodiments of the present application improve the teaching quality of experiments and reduce the failure rate and maintenance time in experiments by designing a nonlinear element characteristic measurement experimental instrument with a simple structure, convenient operation and accurate measurement.

[0111] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0112] In the description of the present invention, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0113] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0114] Although the utility model is described in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes based on the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. A nonlinear element characteristic measurement test instrument, comprising a test instrument panel, on which at least a state display module, a nonlinear element test area, an AC / DC conversion power supply board and a voltage measurement module are arranged; wherein: The state display module at least comprises a plurality of running lights, and any of the running lights is connected to a nonlinear test element in the nonlinear element to be tested area in a one-to-one correspondence; it is characterized in that: The AC / DC conversion power supply board at least includes a power module and a circuit construction module, one end of the power module is connected to the nonlinear test element, the other end of the power module is connected to one end of the circuit construction module, the other end of the circuit construction module is connected to one end of the voltage measurement module, and the other end of the voltage measurement module is connected to an external oscilloscope; Wherein, the circuit building module includes a first connection area, a second connection area and a third connection area; The voltage measurement module at least includes an A / D conversion chip and a voltage measurement calibration circuit; the voltage measurement calibration circuit is at least composed of a reference voltage source, an adjustable potentiometer RV1 and a voltage divider network with a preset voltage divider ratio; wherein one end of the reference voltage source is connected to one end of the adjustable potentiometer RV1, the other end of the adjustable potentiometer RV1 is connected to the A / D conversion chip, and the voltage divider network with a preset voltage divider ratio is connected to the A / D conversion chip.

2. A nonlinear element characteristic measurement test instrument according to claim 1, characterized in that: The status display module also includes a first display screen, a register, a first driver, a display module main controller and a second driver.

3. A nonlinear element characteristic measurement test instrument according to claim 2, characterized in that: One end of the register is connected to the first display screen, and the other end of the register is connected to the display module main controller; the display module main controller is connected in parallel with the multiple running lights through the first driver and the second driver respectively; wherein any of the running lights is also connected in series with a resistor.

4. A nonlinear element characteristic measurement test instrument according to claim 3, characterized in that: The nonlinear element to be tested area is composed of a forward volt-ampere characteristic test area and a reverse volt-ampere characteristic test area; the nonlinear element to be tested area also includes a current measurement module; In the forward volt-ampere characteristic test area, the negative terminal of the nonlinear test element is connected to the current measurement module; in the reverse volt-ampere characteristic test area, the positive terminal of the nonlinear test element is connected to the current measurement module.

5. A nonlinear element characteristic measurement test instrument according to claim 4, characterized in that: The first connection region at least includes a nonlinear element 1, a nonlinear element 2, a nonlinear element 3 and a nonlinear element 4; the positive electrode of the nonlinear element 1 is connected to the negative electrode of the nonlinear element 3, the positive electrode of the nonlinear element 2 is connected to the negative electrode of the nonlinear element 4, the negative electrode of the nonlinear element 1 is connected to the negative electrode of the nonlinear element 2, and the positive electrode of the nonlinear element 3 is connected to the positive electrode of the nonlinear element 4; One end of the power module is connected between the positive electrode of the nonlinear element one and the negative electrode of the nonlinear element three, and the other end of the power module is connected between the positive electrode of the nonlinear element two and the negative electrode of the nonlinear element four.

6. A nonlinear element characteristic measurement test instrument according to claim 5, characterized in that: The second connection area at least includes a preset capacitor group and an analog switch SW1; one end of the preset capacitor group is connected to one end of the analog switch SW1, and the other end of the preset capacitor group is grounded; wherein the preset capacitor includes a plurality of capacitors connected in parallel to each other; The other end of the analog switch SW1 is connected to the third connection region.

7. A nonlinear element characteristic measurement test instrument according to claim 6, characterized in that: The third connection area at least includes a resistor R1, a resistor R2, a resistor R3, a voltage regulator tube D1 and a voltage regulator tube D2; One end of the resistor R1 is connected to the other end of the analog switch SW1, the other end of the resistor R1 is connected to the negative electrode of the voltage-regulating tube D1, the other end of the resistor R1 is also connected to one end of the resistor R2, the other end of the resistor R2 is connected to the negative electrode of the voltage-regulating tube D2, the other end of the resistor R2 is also connected to one end of the resistor R3, the other end of the resistor R3 is connected to the voltage measurement module, and after the positive electrode of the voltage-regulating tube D1 is connected to the positive electrode of the voltage-regulating tube D2, it is also connected to the voltage measurement module.

8. The nonlinear element characteristic measuring test instrument according to claim 7, characterized in that: The voltage measurement module further includes a time base circuit, a negative voltage generator, a third driver, a fourth driver, and a second display; The time base circuit and the negative voltage generator are respectively connected to the A / D conversion chip, and the A / D conversion chip is also connected to the second display through the third driver and the fourth driver.

9. The nonlinear element characteristic measurement test instrument according to claim 8, characterized in that: The voltage measurement calibration circuit also includes a capacitor C1, a resistor R4 and a voltage stabilizing diode D3; The second pin of the reference voltage chip in the reference voltage source is connected to the cathode of the voltage zener diode D3, and the cathode of the voltage zener diode D3 is also connected to one end of the capacitor C1, one end of the resistor R4, and one end pin of the adjustable potentiometer RV1, and the moving pin of the adjustable potentiometer RV1 is connected to the REF pin of the A / D conversion chip; The positive electrode of the voltage zener diode D3 is respectively connected to the first pin of the reference voltage chip, the third pin of the reference voltage chip, the other end of the capacitor C1, and the other end pin of the adjustable potentiometer RV1, and the other end pin of the adjustable potentiometer RV1 is connected to the ACOM pin of the A / D conversion chip; Among them, a preset value of base regulated voltage is provided at the second pin of the reference voltage chip in the reference voltage source. The preset value of the base regulated voltage is passed through the adjustable potentiometer RV1 to obtain the reference source of the target value, and is input to the A / D conversion chip from the REF pin of the A / D conversion chip.

10. The nonlinear element characteristic measuring test instrument according to claim 9, characterized in that: The voltage-dividing network with a preset voltage-dividing ratio at least includes: an analog switch SW2, a resistor R5 and a resistor R6; and a resistor R7 and a capacitor C2 are further included between the voltage-dividing network with a preset voltage-dividing ratio and the A / D conversion chip; A first connection end of the analog switch SW2 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the resistor R6, and the other end of the resistor R6 is connected to the INLO pin of the A / D conversion chip; The second connection end of the analog switch SW2 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to the INHI pin of the A / D conversion chip; the other ends of the resistor R6 and the other ends of the resistor R7 are respectively connected to the two ends of the capacitor C2.

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