Experimental exploration instrument for law of electromagnetic induction

Abstract

The invention discloses an electromagnetic induction law experiment exploration instrument which comprises a base, an electric push rod is installed at one end of the base, and a coil is installed at the other end of the base. The electric push rod comprises an adjustable-speed motor and a telescopic rod; the telescopic speed of the telescopic rod can be changed by adjusting the speed adjusting motor; a magnet is installed at the front end of the telescopic rod, and when the telescopic rod with the magnet stretches out and draws back, the telescopic rod can exactly penetrate into and penetrate out of the coil. A background plate parallel to the telescopic rod is vertically arranged on the base, a speedometer, two groups of light emitting diodes and an oscilloscope are mounted on one side, facing the electric push rod, of the background plate, and the speedometer can measure the movement speed of the magnet; the two groups of light-emitting diodes and the oscilloscope are connected in parallel to two ends of the coil The on-off directions of the two groups of light-emitting diodes are opposite. The electromagnetic induction law experiment exploration instrument can completely realize the whole process from the electromagnetic induction phenomenon to the electromagnetic induction law exploration, and is complete in function and simple to operate.

Description

Technical Field

[0001] The invention relates to a physical experimental device, in particular to an electromagnetic induction law experimental exploration instrument. Background Art

[0002] The law of electromagnetic induction is a difficult part of the electromagnetism part of high school physics, and it is also a basic method for students to understand and obtain physical laws. The law of electromagnetic induction usually includes Faraday's law of electromagnetic induction and Lenz's law. Among them, Faraday's law of electromagnetic induction describes the magnitude of the induced electromotive force, and Lenz's law describes the direction of the induced current.

[0003] At present, when exploring factors related to induced current, textbooks use a closed loop composed of a solenoid coil and an ammeter, as well as an experimental device composed of a bar magnet. By changing the magnetic poles (S pole and N pole), the induced electromotive force generated by four situations is manually inserted and pulled out, and the direction of the induced current is further recorded. This design is greatly affected by human factors and has poor controllability, which is not conducive to the exploration of the law of electromagnetic induction. In addition, the direction of the induced current can only be determined by observing the deflection of the ammeter. It is difficult for all students to intuitively observe the direction and intensity of the induced current at the same time. The teaching demonstration effect is poor, which is not conducive to students' understanding of factors related to the direction of the induced current. In addition, the device has a single function and can only demonstrate the electromagnetic induction phenomenon and cannot quantitatively explore Faraday's law of electromagnetic induction. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an electromagnetic induction law experimental exploration instrument to solve the problems that the existing electromagnetic induction exploration devices are greatly affected by human factors, have poor controllability, poor teaching demonstration effects, single functions, and cannot quantitatively explore Faraday's law of electromagnetic induction.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] An electromagnetic induction law experimental exploration instrument comprises a base, one end of which is equipped with an electric push rod, and the other end of which is equipped with a coil; the electric push rod comprises a speed regulating motor, a swing arm and a telescopic rod, and the rotary motion of the motor is converted into the linear motion of the telescopic rod by the swing arm; the telescopic speed of the telescopic rod can be changed by adjusting the speed regulating motor; a magnet is installed at the front end of the telescopic rod, and the telescopic rod with the magnet can just penetrate into and out of the coil when it is extended and retracted; a background plate is vertically arranged on the base parallel to the telescopic rod, and a speed meter, two groups of light emitting diodes and an oscilloscope are installed on the side of the background plate facing the electric push rod, and the movement speed of the magnet can be measured by the speed meter; the two groups of light emitting diodes and the oscilloscope are connected in parallel to the two ends of the coil; the on and off directions of the two groups of light emitting diodes are opposite.

[0007] Furthermore, each group of light-emitting diodes includes a number of light-emitting lamp beads, thereby forming a diode light strip; the number of light-emitting lamp beads that light up is determined by the current in the closed loop, and the greater the current, the more light-emitting lamp beads that light up.

[0008] Furthermore, the magnet is detachably connected to the telescopic rod.

[0009] Furthermore, the coil housing is provided with a coil box, and through holes are provided at both ends of the coil box, so that the telescopic rod with a magnet can be inserted into or pulled out of the coil through the through holes.

[0010] Furthermore, an on-off switch is provided on the working loop connecting the coil and the light emitting diode.

[0011] Furthermore, the speed meter is a photoelectric speed measuring device.

[0012] Furthermore, the coil box is made of transparent material.

[0013] Furthermore, a circuit diagram reflecting the connection relationship between the light-emitting diode, the on-off switch, the coil and the oscilloscope is provided on the side of the background board facing the electric push rod, and the positions of the symbols representing the light-emitting diode, the on-off switch and the oscilloscope on the circuit diagram correspond to the actual positions of the components on the background board.

[0014] Furthermore, the magnet is a strong magnet.

[0015] Furthermore, the swing arm includes a first swing arm and a second swing arm, one end of the first swing arm is rotatably connected to the output shaft of the speed regulating motor, the other end of the first swing arm is rotatably connected to one end of the second swing arm, and the other end of the second swing arm is rotatably connected to one end of the telescopic rod; a guide block is fixedly provided on the base, a horizontal guide hole is provided in the center of the guide block, and the other end of the telescopic rod passes through the guide hole.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The electromagnetic induction law experimental exploration instrument of the present invention has perfect functions and simple operation, and can completely realize the whole process from electromagnetic induction phenomenon to electromagnetic induction law exploration. It can be used to demonstrate the "electromagnetic induction phenomenon" in classroom teaching. By observing the demonstration experiment, the conditions for generating current using magnetic field can be summarized, and students' observation and generalization ability can be cultivated to help students understand the conditions for the generation of induced current. Students can quantitatively explore the "Faraday's Law of Electromagnetic Induction". The magnetic flux and time are changed respectively by the control variable method to explore the changes in the size of the induced electromotive force. In the process of quantitatively exploring Faraday's law of electromagnetic induction, the instrument drives the magnet on the telescopic rod to move in a straight line by the speed regulating motor, controls the speed of the magnet to insert and pull out the coil, and uses the photoelectric speed measuring device to measure the movement speed of the magnet, so as to ensure the exploration of different magnetic field strengths when the magnetic flux changes are the same, and also ensure the precise control of the magnetic flux change when the magnetic field strength remains unchanged, so as to complete the quantitative exploration of Faraday's law of electromagnetic induction. It can also be used as a demonstration teaching aid for experimental exploration in the teaching process of "Lenz's Law". By using the unidirectional conductivity of light-emitting diodes, the direction and intensity of the induced current can be intuitively displayed through the order and number of two sets of reversely connected LED gradient lights lighting up, thereby achieving an intuitive display of Lenz's Law. The experimental phenomena are obvious and interesting, which is conducive to stimulating students' enthusiasm for scientific exploration.

[0018] 2. The electromagnetic induction law experimental exploration instrument of the present invention adopts an electric push rod to replace the traditional manually movable magnet, which reduces the influence of human factors and increases the controllability of the operation. It has a simple structure, is easy to carry and easy to operate, and brings great convenience to classroom demonstrations and student group experiments.

[0019] 3. The results of the electromagnetic induction law experimental exploration instrument of the present invention are intuitive and reliable. The instrument adopts single-chip microcomputer technology, directly measures the movement speed of the magnet through photoelectric speed measurement, and accurately controls the change of magnetic flux; through a simple oscilloscope, directly measures and displays the size of the induced electromotive force. The measurement results are accurate and reliable. Two sets of reversely connected LEDs are used to display the intensity and direction of the induced current. The combination of the three displays intuitively gives the relationship between the induced electromotive force, the induced current and the change of magnetic flux, thereby intuitively and comprehensively demonstrating the law of electromagnetic induction. In addition, the present invention uses electronic technology to present complex experimental phenomena in the form of light signals and images. The phenomena of the instrument are intuitive and simple to operate, which is more convenient for students to observe and analyze, and is conducive to cultivating observation ability and logical thinking ability; it can also help students understand the law of electromagnetic induction and Lenz's law. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the electromagnetic induction law experimental exploration instrument of the present invention;

[0021] Figure 2A circuit for connecting a coil, a light emitting diode, an on-off switch and an oscilloscope in the experimental exploration instrument of the present invention;

[0022] Figure 3 The figure is a relationship diagram between the moving speed of the magnet and the maximum value of the induced electromotive force measured by the experimental exploration instrument of the present invention;

[0023] Figure 4 The figure is a relationship diagram between the number of magnets and the maximum value of the induced electromotive force measured by the experimental exploration instrument of the present invention.

[0024] In the figure, base 1, electric push rod 2, coil 3, speed regulating motor 4, telescopic rod 5, magnet 6, background plate 7, speed meter 8, light emitting diode 9, oscilloscope 10, coil box 11, on-off switch 12, speed measuring probe 13, display panel 14, swing arm 15, first swing arm 16, second swing arm 17, guide block 18. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention are further described in detail below in conjunction with specific examples.

[0026] The electromagnetic induction law experimental exploration instrument of the present invention is designed and manufactured according to the electromagnetic induction law. When the magnetic flux of a closed coil changes, an induced electromotive force and an induced current will be generated in the closed coil. This phenomenon is called electromagnetic induction. Among them, the magnitude of the induced electromotive force is equal to the time rate of change of the magnetic flux, and the direction of the induced current is determined by Lenz's law, that is, the magnetic field generated by the induced current always hinders the change of the original magnetic field.

[0027] Based on the curriculum standards and considering the needs of inquiry-based teaching, the key lies in the change of magnetic flux, the change of magnetic field strength, the measurement of induced electromotive force, and the intuitive display of induced current strength and direction. To this end, the single-chip microcomputer technology is used to control and measure the movement speed of the magnet in combination with the speed regulating motor and the photoelectric speed measuring device to achieve the control of the rate of change of magnetic flux; the oscilloscope is used to measure the magnitude of the induced electromotive force. The unidirectional conductivity of the LED is used to intuitively display the induced current strength and direction. Such a design can conveniently use the control variable method to explore the law of electromagnetic induction in classroom demonstrations and student group experiments.

[0028] 1. Implementation

[0029] like Figure 1As shown, an electromagnetic induction law experimental exploration instrument comprises a base 1, one end of the base 1 is equipped with an electric push rod 2, and the other end is equipped with a coil 3; the electric push rod 2 comprises a speed regulating motor 4, a swing arm 15 and a telescopic rod 5, and the swing arm 15 converts the rotational motion of the speed regulating motor 4 into the linear motion of the telescopic rod 5; the telescopic speed of the telescopic rod 5 can be changed by adjusting the speed regulating motor 4; a magnet 6 is installed at the front end of the telescopic rod 5, and the telescopic rod 5 with the magnet 6 can just penetrate into and out of the coil 3 when it is extended and retracted; a background plate 7 is vertically arranged on the base 1 parallel to the telescopic rod 5, and a speed meter 8, two groups of light emitting diodes 9 and an oscilloscope 10 are installed on the side of the background plate 7 facing the electric push rod 2, and the movement speed of the magnet 6 can be measured by the speed meter 8; the two groups of light emitting diodes 9 and the oscilloscope 10 are connected in parallel to the two ends of the coil 3; the on and off directions of the two groups of light emitting diodes 9 are opposite.

[0030] In specific implementation, each group of light-emitting diodes 9 includes a number of light-emitting lamp beads, thereby forming a diode light strip; the number of lamp beads that light up is determined by the current in the closed loop. The larger the current, the more lamp beads that light up. During the experiment, the more lamp beads light up, the greater the intensity of the induced current. In this way, the intensity of the induced current can be judged according to the number of lamp beads that light up. All students can intuitively observe the intensity of the induced current, which enhances the fun of experimental exploration. The teaching demonstration effect is good, which is conducive to all students to understand the relationship between the intensity of the induced current and the intensity of the magnetic field, deeply understand the law of electromagnetic induction, and stimulate students' interest in scientific exploration. The diode light strip can be purchased directly from the market.

[0031] In specific implementation, each group of light emitting diodes 9 includes 20 light emitting lamp beads, so that the change of the induced current intensity can be clearly observed and the use cost of the lamp beads can be saved.

[0032] In a specific implementation, the magnet 6 is detachably connected to the telescopic rod 5. In this way, the magnetic field strength can be changed by increasing or decreasing the number of the magnets 6, so as to quantitatively explore the relationship between the magnetic field strength and the induced electromotive force.

[0033] During specific implementation, the magnet 6 is directly adsorbed on the front end of the telescopic rod 5. This makes it convenient to install and remove the magnet 6.

[0034] In specific implementation, the magnet 6 is a strong magnet. The strong magnet has a large suction force, which can ensure that the magnet 6 is firmly adsorbed on the front end of the telescopic rod 5 to prevent it from falling.

[0035] In a specific implementation, the coil 3 is provided with a coil box 11, and through holes are provided at both ends of the coil box 11, so that the telescopic rod 5 with the magnet 6 can be inserted into or pulled out of the coil 3 through the through holes. This can prevent external substances from contaminating the coil 3, protect the wires and connection points from environmental factors, extend the service life of the coil 3, and avoid the risk of electric shock, ensuring the safety of the user.

[0036] In specific implementation, the coil box 11 is made of transparent material, so that it is easy to observe whether the telescopic rod is inserted into the coil 3, thereby avoiding students from misinterpreting the electromagnetic induction phenomenon.

[0037] In specific implementation, an on-off switch 12 is provided on the working loop connecting the coil 3 and the light emitting diode 9. The on-off switch 12 can be provided to facilitate the connection and disconnection of the light emitting diode, thereby facilitating students to understand the conditions for the occurrence of electromagnetic induction phenomenon.

[0038] In specific implementation, the speed meter 8 is a photoelectric speed measuring device based on a 51 single chip microcomputer. The photoelectric speed measuring device utilizes the characteristics of light speed propagation to achieve high-precision and high-resolution speed measurement, thereby achieving precise control of magnetic flux changes.

[0039] In specific implementation, a circuit diagram showing the connection relationship between the light emitting diode 9, the on-off switch 12, the coil 3 and the oscilloscope 10 is provided on one side of the background plate 7 facing the electric push rod 2, and the position of the symbols representing the light emitting diode 9, the on-off switch 12 and the oscilloscope 10 on the circuit diagram corresponds to the actual position of the components on the background plate 7. In this way, it is convenient for students to intuitively grasp the circuit connection relationship of this experiment, understand the direction of the current, and the conditions for the generation of the induced current and the induced electromotive force.

[0040] In specific implementation, the speed meter 8 includes a speed measuring probe 13 and a display panel 14. The speed measuring probe 13 is directly opposite to the telescopic rod 5 to measure the movement speed of the magnet. After the built-in single-chip microcomputer program of the speed meter 8 processes the data collected by the speed measuring probe 13, the movement speed of the magnet 6 can be directly displayed through the display panel 14.

[0041] The present invention converts the rotational motion of the speed regulating motor 4 into the linear motion of the telescopic rod 5 through the swing arm 15. Specifically, the swing arm 15 includes a first swing arm 16 and a second swing arm 17, one end of the first swing arm 16 is rotatably connected to the output shaft of the speed regulating motor 4, the other end of the first swing arm 16 is rotatably connected to one end of the second swing arm 17, and the other end of the second swing arm 17 is rotatably connected to one end of the telescopic rod 5.

[0042] In specific implementation, a guide block 18 is fixedly provided on the base 1, and a horizontal guide hole is provided in the center of the guide block 18, through which the telescopic rod 5 passes. In this way, the guide block 18 not only supports the telescopic rod 5, but also guides the movement of the telescopic rod 5, making the movement of the telescopic rod 5 more stable and reliable, and avoiding the position of the telescopic rod 5 from being offset and failing to accurately extend into the coil 3, which affects the exploration of the law of electromagnetic induction.

[0043] During the specific implementation, the base 1 and the background plate 7 are both acrylic plates; the length and width of the base 1 are 700mm*300mm; the height of the background plate 7 is 620mm; the power supply used is a 12V DC regulated power supply; a 12V JGB37-520 reduction motor is installed in the speed regulating motor 4, and the speed of the speed regulating motor 4 is regulated by regulating the reduction motor.

[0044] The circuit diagram of the light emitting diode, oscilloscope, on-off switch and coil in the experimental instrument of the present invention is as follows: Figure 2 shown.

[0045] Working principle: The electromagnetic induction law experimental exploration instrument of the present invention can completely realize the whole process from electromagnetic induction phenomenon to electromagnetic induction law exploration. First of all, before demonstrating and exploring the electromagnetic induction law, it is necessary to turn on the power of the electric push rod, the tachometer and the oscilloscope. When demonstrating the electromagnetic induction phenomenon, the speed of the speed regulating motor and the number of magnets at the front end of the telescopic rod are fixed, the on-off switch is closed, and when the magnet is inserted into and pulled out of the coil, the light-emitting diode lights up, indicating that an induced current is generated in the circuit, that is, an electromagnetic induction phenomenon is generated. When quantitatively exploring Faraday's law of electromagnetic induction, when the number of magnets remains unchanged, the speed of the speed regulating motor is adjusted to control the speed of the magnet inserting and pulling out of the coil, and the speed of the magnet inserting and pulling out of the coil measured by the tachometer and the size of the electromotive force displayed in the oscilloscope are combined to quantitatively explore the relationship between the size of the electromotive force and the speed of the magnet movement; when the speed of the magnet inserting and pulling out of the coil remains unchanged, the number of magnets at the front end of the telescopic rod is increased or decreased, and the size of the electromotive force displayed in the oscilloscope is combined to quantitatively explore the relationship between the size of the electromotive force and the number of magnets; thereby realizing the quantitative exploration of Faraday's law of electromagnetic induction. When adjusting the telescopic rod to extend or retract, the telescopic rod can be extended or shortened by adjusting the rotation direction of the motor, thereby effectively controlling the order in which the magnets move away from or approach the coil. When demonstrating Lenz's law, the speed of the speed regulating motor and the number of magnets at the front end of the telescopic rod are fixed, and the order in which the light-emitting diodes light up when the magnets are inserted into and pulled out of the coil is observed to intuitively display the direction of the induced current, thereby achieving an intuitive demonstration of Lenz's law.

[0046] 2. Experimental Exploration Process and Conclusion

[0047] (I) Research on “Faraday’s Law of Electromagnetic Induction”

[0048] By changing the speed of magnet movement and the magnetic field strength (i.e. the number of magnets) respectively, we explore the factors that affect the magnitude of the induced electromotive force.

[0049] (1) Keep the magnetic field strength (number of magnets) unchanged, change the speed of the magnets, and quantitatively explore the relationship between the speed of the magnets and the induced electromotive force.

[0050] Change the speed of inserting and removing the magnet, observe the number of light-emitting diode (LED) beads that light up, the changes in the oscilloscope waveform and the recorded voltage value. The specific steps are as follows:

[0051] a. Turn on the tachometer, oscilloscope power supply and on-off switch;

[0052] b. Adjust the coil box to a suitable position to avoid contact with the telescopic rod;

[0053] c. Determine the number of magnets according to the needs of the investigation and attach them vertically to the top of the telescopic rod;

[0054] d. Turn on the power of the speed regulating motor, and then determine the rotation direction of the motor shaft to determine the initial movement direction of the magnet;

[0055] e. Adjust the rotation speed of the speed regulating motor and change the movement speed of the magnets in groups;

[0056] f. Record data.

[0057] Under the condition that the number of magnets remains unchanged, the experimental record table of the magnet movement speed and the magnitude of the induced electromotive force is shown in Table 1.

[0058] Table 1 Experimental record of magnet moving speed and induced electromotive force

[0059] Serial number Magnet moving speed (km / h) Maximum induced electromotive force (v) 1 2.0 0.12 2 3.0 0.18 3 4.0 0.25 4 5.0 0.33 5 6.0 0.42 6 7.0 0.53

[0060] The relationship between the speed of magnet movement and the maximum value of induced electromotive force is as follows Figure 3 As shown. Figure 3 As can be seen from Table 1, under the condition that the number of magnets remains unchanged, the faster the magnets move, the greater the induced electromotive force generated in the circuit, and they are in direct proportion, which is consistent with the law of electromagnetic induction.

[0061] (2) Keep the speed of the magnet unchanged, change the magnetic field strength (number of magnets), and quantitatively explore the relationship between magnetic field strength and induced electromotive force.

[0062] Keep the speed of the magnet moving device unchanged, change the number of magnets, record the maximum voltage displayed by the oscilloscope, and observe the number of corresponding LED lights that light up. The specific steps are as follows:

[0063] a. Turn on the tachometer, oscilloscope power supply and on-off switch;

[0064] b. Adjust the coil box to a suitable position to avoid contact with the telescopic rod;

[0065] c. Determine the speed of the magnet according to the needs of the investigation;

[0066] d. Turn on the power of the speed regulating motor, and then determine the rotation direction of the motor shaft to determine the initial movement direction of the magnet;

[0067] e. Change the number of magnets in groups;

[0068] f. Record data.

[0069] Under the condition that the moving speed of the magnets remains constant, the experimental record table of the number of magnets and the magnitude of the induced electromotive force is shown in Table 2.

[0070] Table 2 Experimental record of the number of magnets and the magnitude of the induced electromotive force

[0071] Serial number Number of magnets Maximum induced electromotive force (v) 1 1 0.28 2 2 0.48 3 3 0.68 4 4 0.91 5 5 1.1 6 6 1.32

[0072] The relationship between the number of magnets and the maximum induced electromotive force is as follows Figure 4 As shown. Figure 4 It can be seen from Table 2 that, under the condition that the moving speed of the magnet remains unchanged, the more magnets there are, the greater the induced electromotive force generated in the circuit, and they are in direct proportion, which is consistent with the law of electromagnetic induction.

[0073] (II) Research on Lenz's Law

[0074] Keep the speed of the strong magnet moving device and the number of strong magnets constant. Insert and remove the magnets, observe the number and direction of the LED gradient lamp beads that light up, and pay attention to the changes in the initial waveform of the oscilloscope and the recorded voltage value. The specific steps are as follows:

[0075] (1) Turn on the power of the tachometer and oscilloscope;

[0076] (2) Adjust the coil box to a suitable position to avoid contact with the telescopic rod;

[0077] (3) Turn on the power of the speed regulating motor, and then determine the rotation direction of the motor shaft, thereby determining the initial movement direction of the magnet;

[0078] (4) Close the on-off switch in the circuit to turn on the LED gradient light;

[0079] (5) Determine the push rod speed;

[0080] (6) Observe the flashing direction and number of LED lights, observe the graph on the oscilloscope, and record the maximum value.

[0081] Through experiments to explore the relationship between the N / S pole magnet and the induced current when it is inserted and pulled out of the coil, keep the moving speed of the strong magnet unchanged. Turn on the power, insert and pull out multiple times (when inserting: the magnetic field strength increases, the magnetic flux increases, hindering its increase, and generating a magnetic field opposite to the original magnetic field, which is further manifested as the direction of the induced current. When pulling out: the magnetic field strength decreases, the magnetic flux decreases, hindering its decrease, and generating a magnetic field consistent with the original magnetic field. Verification formula: "come and go, refuse to stay, increase and decrease are the same"), the spiral coil generates an induced electromotive force, which is further converted into an induced current flowing through the LED lamp and manifested as current in different directions. The direction in which the LED light turns on can verify the concept of Lenz's law: the magnetic field of the induced current always hinders the change in the magnetic flux that causes the induced current.

[0082] In addition, during the experiment, by observing the number of LED lights that light up, the size of the induced current can be determined. The more LEDs that light up, the greater the induced current.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. An electromagnetic induction law experimental exploration instrument, characterized in that: The utility model comprises a base, one end of which is equipped with an electric push rod, and the other end of which is equipped with a coil; the electric push rod comprises a speed regulating motor, a swing arm and a telescopic rod, and the rotary motion of the motor is converted into the linear motion of the telescopic rod through the swing arm; the telescopic speed of the telescopic rod can be changed by adjusting the speed regulating motor; A magnet is installed at the front end of the telescopic rod, and the telescopic rod with the magnet can just penetrate into and out of the coil when it is extended or retracted; a background plate is vertically arranged on the base parallel to the telescopic rod, and a speed meter, two groups of light emitting diodes and an oscilloscope are installed on the side of the background plate facing the electric push rod, and the movement speed of the magnet can be measured by the speed meter; the two groups of light emitting diodes and the oscilloscope are connected in parallel to the two ends of the coil; the on and off directions of the two groups of light emitting diodes are opposite.

2. The electromagnetic induction law experimental exploration instrument according to claim 1 is characterized in that: Each group of light-emitting diodes includes a number of light-emitting lamp beads, thus forming a diode light strip; the number of light-emitting lamp beads that light up is determined by the current in the closed loop. The larger the current, the more light-emitting lamp beads that light up.

3. The electromagnetic induction law experimental exploration instrument according to claim 1 is characterized in that: The magnet is detachably connected to the telescopic rod.

4. The electromagnetic induction law experimental exploration instrument according to claim 1 is characterized in that: The coil outer shell is provided with a coil box, and through holes are opened at both ends of the coil box, so that the telescopic rod with a magnet can be inserted into or pulled out of the coil through the through holes.

5. The electromagnetic induction law experimental exploration instrument according to claim 4 is characterized in that: The coil box is made of transparent material.

6. The electromagnetic induction law experimental exploration instrument according to claim 1, characterized in that: An on-off switch is arranged on the working loop connecting the coil and the light emitting diode.

7. The electromagnetic induction law experimental exploration instrument according to claim 6, characterized in that: A circuit diagram reflecting the connection relationship between the light-emitting diode, the on-off switch, the coil and the oscilloscope is provided on one side of the background plate facing the electric push rod. The positions of the symbols representing the light-emitting diode, the on-off switch and the oscilloscope on the circuit diagram correspond to the actual positions of the components on the background plate.

8. The electromagnetic induction law experimental exploration instrument according to claim 1, characterized in that: The speed meter is a photoelectric speed measuring device.

9. The electromagnetic induction law experimental exploration instrument according to claim 1, characterized in that: The magnet is a strong magnet.

10. The electromagnetic induction law experimental exploration instrument according to claim 1, characterized in that: The swing arm includes a first swing arm and a second swing arm, one end of the first swing arm is rotatably connected to the output shaft of the speed regulating motor, the other end of the first swing arm is rotatably connected to one end of the second swing arm, and the other end of the second swing arm is rotatably connected to one end of the telescopic rod; a guide block is fixedly provided on the base, a horizontal guide hole is provided in the center of the guide block, and the other end of the telescopic rod passes through the guide hole.

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