CN113096503B

CN113096503B - Ammeter demonstrating board

Info

Publication number: CN113096503B
Application number: CN202110369967.7A
Authority: CN
Inventors: 李新亚
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2023-05-16
Anticipated expiration: 2041-04-02
Also published as: CN113096503A

Abstract

The invention relates to an ammeter teaching board, which comprises three mutually independent and unstructured multimeter teaching boards (1), a voltmeter teaching board (8) and an ammeter teaching board (14). The front image of the ammeter drawn on the ammeter demonstrating board is far larger than the real image, so that the structure is clear and clear at a glance; the ammeter demonstrating board is light in weight, convenient to carry and labor-saving; the electric meter demonstrating board plays a role in demonstrating, and although the electric meter front image is drawn, the movable components on the electric meter are still movable and vivid on the electric meter demonstrating board; the teaching effect of the ammeter teaching board is superior to that of an ammeter, an ammeter hanging chart and a multimedia teaching aid; the ammeter demonstrating board has low cost, is easy to popularize and has a plurality of beneficiaries; the ammeter demonstrating board can produce strong stimulation to the vision of students, can fully mobilize the study enthusiasm of students, can obtain better teaching effect, can improve teaching efficiency, can alleviate teacher's intensity of labour.

Description

Ammeter demonstrating board

Technical Field

The invention relates to an ammeter demonstrating board, in particular to an ammeter demonstrating board which can generate strong stimulation on vision of students, fully mobilize learning enthusiasm of the students, obtain better teaching effect, improve teaching efficiency and lighten labor intensity of teachers.

Background

Ammeter, some students see, but few students do so. Teachers teach the use of electricity meters, students lack perceptual knowledge, and learning is difficult and heavy.

The teacher takes the electric belt into the classroom, and the students sitting in front can not see the scales and the pointers, and the students sitting in back can only see the outline.

The ammeter is drawn on paper to form a hanging chart. The hanging chart is more clear than the real object, and knows where to be the pointer and where to be the binding post. However, the hanging chart is dead, the teacher speaks that the pointer deflects, and the pointer on the hanging chart is not moving. The teaching effect is greatly reduced when the teaching is not matched with the figure.

With the development of technology, multimedia teaching has been developed. The teacher takes the computers on shoulder and holds the cameras, and after the teacher walks into the classroom, the teacher grasps the time to start, preheats and hangs the curtain.

Multimedia teaching is good but has drawbacks.

Firstly, the middle of the blackboard is covered by the curtain, so that the blackboard writing function of the blackboard is basically lost; the curtain is temporarily retracted to vacate the blackboard, and the curtain is unfolded when needed, so that the blackboard is feasible, but time-consuming; the curtain hangs to the corner of the wall, but is uncomfortable for the diagonal student looking with his head or eyes obliquely.

Secondly, the preparation time is long, students need to be tolerant to waiting, and the teaching time is not fully utilized.

Thirdly, students have more visual enjoyment and less thinking activity.

Fourth, the power consumption is large.

Fifthly, the investment is larger.

Disclosure of Invention

The technical problem to be solved by the invention is to provide the ammeter demonstrating board which can generate strong stimulation to the vision of students, fully mobilize the learning enthusiasm of the students, obtain better teaching effect, improve teaching efficiency and lighten the labor intensity of teachers.

In order to solve the technical problems, the technical scheme of the invention is as follows:

an ammeter demonstrating board is a teaching aid for a physical teacher in junior middle school or high school to teach students an ammeter using method in classroom teaching or extracurricular coaching.

The ammeter demonstrating board comprises three independent and unstructured multimeter demonstrating boards, a voltmeter demonstrating board and an ammeter demonstrating board.

The universal meter teaching board comprises a universal meter teaching base plate, and a universal meter front image and a meter pen which are drawn on the white outer surface of the universal meter teaching base plate.

The universal meter teaching base plate is a rectangular light plate and is made of soft magnetic materials, and the area of the outer surface of the universal meter teaching base plate is far larger than the area of the front surface of the universal meter; the drawn multimeter front image is much larger than the multimeter front image.

The drawn graph of the mechanical zeroing screw on the front image of the universal meter is replaced by a mechanical zeroing circular plate which can rotate around a mechanical zeroing shaft but cannot move along the axial direction, and the mechanical zeroing shaft is fixedly connected to the corresponding position of the teaching baseplate of the universal meter.

On the front image of the drawn multimeter, the graph of the ohm zeroing knob is replaced by an ohm zeroing circular plate which can rotate around an ohm zeroing shaft but cannot move along the axial direction, and the ohm zeroing shaft is fixedly connected to the corresponding position of the multimeter teaching baseplate.

On the drawn front image of the multimeter, the graph of the range selection switch is replaced by a rotary table which can rotate around a range selection shaft but can not move along the axial direction, the shape of the rotary table is the same as the shape of a real object of the range selection switch, and the range selection shaft is fixedly connected to the corresponding position of the multimeter teaching bottom plate.

On the drawn front image of the universal meter, the graph of the pointer of the universal meter is replaced by a movable short straight thin rod with magnetism; the thin rod can be adsorbed on the dial of the drawn front image of the universal meter, so that a teacher can conveniently change the position of the thin rod relative to the dial, and deflection of a pointer of the universal meter is simulated.

On the drawn front image of the multimeter, the figure of the "+" jack is a real round hole penetrating through the teaching baseplate of the multimeter at the corresponding position.

On the drawn front image of the multimeter, the figure of the "-" jack is a real round hole penetrating through the teaching baseplate of the multimeter at the corresponding position.

The meter pen consists of a red meter pen and a black meter pen; the red gauge pen and the black gauge pen can be respectively inserted into a "+" jack and a "-" jack on the universal meter demonstration board.

The voltmeter teaching board comprises voltmeter front images drawn on white outer surfaces of a voltmeter teaching board and a voltmeter teaching board.

The voltmeter represents a teaching bottom plate which is a rectangular light plate, and the area of the outer surface of the teaching bottom plate is far larger than that of the front surface of the voltmeter; the front image of the drawn voltmeter is much larger than the front image of the voltmeter.

The drawing is characterized in that on the front image of the voltmeter, the graph of the voltmeter pointer is replaced by a rotatable voltmeter pointer sheet and voltmeter circular plate combination; the voltmeter pointer sheet is a rigid strip-shaped narrow sheet, and the front end of the voltmeter pointer sheet is pointed; the outer diameter of the voltmeter circular plate is far smaller than the length of the voltmeter pointer sheet, a circular hole is formed in the center of the voltmeter pointer sheet, the circular hole is formed in the rear end of the voltmeter pointer sheet, a screw penetrates through the upper circular hole to install the voltmeter pointer sheet on the voltmeter teaching base plate, and the installation point is located on the center of a scale disc circular arc line on the drawn voltmeter front image; the voltmeter pointer sheet is pushed by hand to rotate around the axis of the screw along the outer surface of the voltmeter pointer board, so that the deflection of the voltmeter pointer is simulated, and the static friction force can keep the voltmeter pointer relatively static when the hand is separated from the voltmeter pointer sheet.

On the front image of the drawn voltmeter, the right binding post of the voltmeter is a circle, and a "-" sign is marked on the circle.

On the front image of the drawn voltmeter, the binding posts in the voltmeter are circles, and the numbers "3" are marked on the circles.

On the front image of the drawn voltmeter, the left binding post of the voltmeter is a circle, and the number "15" is marked on the circle.

The ammeter teaching board comprises an ammeter front image drawn on the white outer surface of the ammeter teaching board and the ammeter teaching board.

The ampere indicating teaching bottom plate is a rectangular light plate, and the area of the outer surface of the teaching bottom plate is far larger than that of the front surface of the ampere meter; the drawn front image of the ammeter is much larger than the front image of the ammeter.

On the drawn ammeter front image, the graph of the ammeter pointer is replaced by a rotatable ammeter pointer sheet and ammeter circular plate combination; the ammeter pointer sheet is a rigid strip-shaped narrow sheet, and the front end of the ammeter pointer sheet is pointed; the outer diameter of the ampere meter circular plate is far smaller than the length of the ampere meter pointer sheet, a circular hole is formed in the center of the ampere meter circular plate, the ampere meter circular plate is positioned at the rear end of the ampere meter pointer sheet, a screw penetrates through the upper circular hole of the ampere meter circular plate to be installed on the ampere meter teaching baseplate, and the installation point is positioned at the center of a circle arc of a scale disc on the drawn ampere meter front image; the ammeter pointer piece is pushed by hand to rotate along the outer surface of the ammeter pointer base plate around the axis of the screw, so that deflection of the ammeter pointer is simulated, and static friction force can keep the ammeter pointer relatively static when the hand is separated from the ammeter pointer piece.

On the drawn ammeter front image, the ammeter right binding post is a circle, and a "-" sign is marked on the circle.

On the drawn ammeter front image, the binding posts in the ammeter are circles, and the number of 0.6 is marked on the circles.

On the drawn ammeter front image, the ammeter left binding post is a circle, and the number "3" is marked on the circle.

The ammeter demonstrating board is visual and vivid, can generate strong stimulation to the vision of students, can fully mobilize the learning enthusiasm of the students, can obtain better teaching effect, can improve teaching efficiency, and can lighten the labor intensity of teachers.

By utilizing the universal meter demonstrating board, the following demonstrating teaching can be performed on high school students:

first, introduce universal meter

(1) The function of a multimeter is described.

(2) The names and roles of the various moving components on the multimeter are taught.

(3) Guiding students to observe the relative positions of the resistor scale and the voltage and current combined scale, wherein the distribution condition of scale marks on the resistor scale and the voltage and current combined scale is that a 0 scale mark on the resistor scale is positioned at the leftmost side (the right side of an observer) of the resistor scale and a 0 scale mark on the voltage and current combined scale is positioned at the rightmost side of the combined scale; and guiding students to compare the uniformity and arrangement sequence of the scale values on the resistor scale, the voltage and current combined scale.

(4) The physical meaning of the following symbols on a multimeter is taught:

second, general use method of universal meter is taught

(5) And rotating the mechanical zeroing circular plate, enabling the thin rod to move to the 0 scale mark of the voltage and current shared scale, and simulating and adjusting the mechanical zeroing screw to enable the pointer of the universal meter to be zeroed.

(6) The red meter pen holder "+" jack and the black meter pen holder "-" jack are simulated.

Third, universal meter measuring resistor

(7) And rotating the turntable, simulating the rotating range selection switch, and placing the rotating range selection switch in a proper range gear of the resistor gear.

(8) The resistance measurement is to be firstly ohm zeroed: the red meter pen and the black meter pen are in short circuit, the ohm zeroing circular plate is rotated, the ohm zeroing knob is simulated to be rotated, the thin rod is moved to the leftmost side of the resistance scale (the right side of an observer), the pointer of the simulated multimeter is deflected to the 0 scale mark, and the operation is ohm zeroing; then the red meter pen and the black meter pen are separated, the thin rod is moved to the rightmost side of the resistance scale, and after the red meter pen and the black meter pen are simulated to be separated, the pointer of the universal meter returns to the rightmost side of the resistance scale.

(9) Measuring resistance: the red meter pen and the black meter pen are respectively overlapped with two ends of the measured resistor, a human body cannot be connected with the measured resistor in parallel, the thin rod is moved to the middle of the resistor scale, the pointer of the analog multimeter deflects when the resistor is measured, then the indication value of the pointer of the analog multimeter is simulated and read, and then the measured value is calculated:

Measured value = instruction value x magnification

(10) And the whole process is coherent to simulate the resistance measurement.

(11) The red meter pen and the black meter pen are respectively overlapped with two ends of the measured resistor, so that the thin rod stays near the rightmost side of the resistor scale or near the 0 scale mark, the deflection angle of the pointer of the analog multimeter is small or large, and in order to reduce measurement errors, how to change the resistor measuring range for retesting is explained.

(12) Emphasis is placed on changing the resistance range and retesting the resistance still requires an early ohmic zeroing.

(13) The multimeter pointer will deflect when measuring the resistance. A battery is arranged in the original universal meter, and the battery is connected into a circuit when the equivalent range selection switch is arranged in a resistance gear; the battery is idle when the range selector switch is placed in other gear positions.

Fourth, universal meter measures DC voltage

(14) The rotary table is rotated to point to the direct-current voltage gear, and the analog rotary range selection switch is arranged in the direct-current voltage gear.

(15) The selection of analog dc voltage ranges is taught while.

(16) The universal meter is connected with the tested circuit in parallel; then simulating the contact of the red meter pen with a high potential point of the tested circuit, the contact of the black meter pen with a low potential point of the tested circuit, moving the thin rod to stay in the middle of the dial, and simulating the pointer deflection of the universal meter when the direct current voltage is tested; the black meter pen can be simulated to be contacted with a high potential point of a tested circuit, the red meter pen is simulated to be contacted with a low potential point of the tested circuit, the thin rod is contacted with the right side of the dial, and the universal meter pointer is simulated to collide with the right side watchcase, so that the universal meter pointer can be caused to collide and bend, and the impression of students is deepened.

(17) Moving the thin rod to stay in the middle of the dial, and simulating deflection of the pointer of the universal meter when DC voltage is tested; the indication of the multimeter pointer is then read in a simulated manner and the measured value is calculated:

(18) The thin rod is kept near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, the deflection angle of the pointer of the analog multimeter is too small or too large, and in order to reduce measurement errors, the method is used for explaining how to change the direct current voltage range and retest.

Fifth, universal meter measures AC voltage

(19) The rotary table is rotated to point to the alternating voltage gear, and the analog rotary range selection switch is arranged in the alternating voltage gear.

(20) The selection of analog ac voltage ranges is taught while.

(21) The universal meter is connected with the tested circuit in parallel to test the alternating voltage: the analog red meter pen and the black meter pen are randomly overlapped with two ends of the tested circuit respectively, and the difference between the analog red meter pen and the black meter pen and the tested direct current voltage is pointed out.

(22) Moving the thin rod to stay in the middle of the dial, and simulating deflection of the pointer of the universal meter when testing alternating voltage; then the indication value of the pointer of the universal meter is simulated and read, and the measured value is calculated:

(23) The thin rod is kept near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, the deflection angle of the pointer of the analog multimeter is too small or too large, and in order to reduce measurement errors, how to change the AC voltage range for retesting is taught.

Six, universal meter measures direct current

(24) The rotary table is rotated to point to the direct current gear, and the analog rotary range selection switch is arranged in the direct current gear.

(25) The selection of analog dc current ranges is taught while.

(26) The universal meter is connected with the tested circuit in series; disconnecting the tested circuit, overlapping the analog red meter pen and the black meter pen with two ends of the disconnected part respectively, focusing on the fact that direct current flows into the universal meter from the red meter pen and flows out from the black meter pen, then moving the thin rod to stay in the middle of the dial, and simulating pointer deflection of the universal meter when the direct current is tested; intentional misconnections may be made if desired: direct current flows into the multimeter from the black meter pen and flows out from the red meter pen, the thin rod is contacted with the right side of the dial, and the pointer of the multimeter is simulated to collide with the watch case on the right side, so that the pointer of the multimeter can be caused to collide and bend, and the impression of students is deepened; even the universal meter can be intentionally simulated to be connected with the tested circuit in parallel, so that the meter head of the universal meter is burnt out, and the students can inscribe the heart.

(27) Moving the thin rod to stay in the middle of the dial, and simulating deflection of the pointer of the universal meter when DC current is tested; then the indication value of the pointer of the universal meter is simulated and read, and the measured value is calculated:

(28) The thin rod is kept near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, the deflection angle of the pointer of the analog multimeter is too small or too large, and in order to reduce measurement errors, the method is used for explaining how to change the direct current measuring range and retest.

(29) When the universal meter is not used for a short time, the rotary table is rotated to point to the maximum range gear of the alternating voltage gear, and the range selection switch is simulated to be placed in the maximum range gear of the alternating voltage gear, so that the reason is explained.

(30) When the multimeter is not used for a long time, the battery in the multimeter is taken out except for the maximum range of the range selection switch to be placed in the alternating-current voltage range, and the reason is described.

By utilizing the voltmeter demonstrating board, the following demonstrating teaching can be performed on junior middle school or high school students:

(1) The meaning of the symbol "-" on the right binding post of the voltmeter; the meaning of the number "3" on the binding post in the voltmeter; the meaning of the number "15" on the left post of the voltmeter.

(2) The full bias voltage on the dial of the voltmeter is 3V and 15V; if a 3V measuring range is selected, the measured value (the indicated value is the measured value) is read according to the scale with the full bias voltage of 3V, and if a 15V measuring range is selected, the measured value is read according to the scale with the full bias voltage of 15V.

(3) The direct current voltage of the tested circuit is estimated to be about 8V, the direct current voltage of the tested circuit is measured, which measuring range is selected by the analysis voltmeter, which two binding posts are selected, and which scale is selected to read the measured value.

(4) The voltage of the dry battery is measured by a voltmeter, which measuring range should be selected by the voltmeter, which two binding posts should be selected, and which scale should be selected to read the measured value.

(5) The voltmeter is connected in parallel with the measured voltage circuit.

(6) If 3V measuring range is selected to test direct-current voltage, two ends of one wire are respectively connected with a binding post in the voltmeter and a high potential point of a tested circuit, and two ends of the other wire are respectively connected with a right binding post of the voltmeter and a low potential point of the tested circuit; if a 15V measuring range is selected, two ends of one wire for simulation are respectively connected with a left binding post of the voltmeter and a high potential point of a tested circuit, and two ends of the other wire are respectively connected with a right binding post of the voltmeter and a low potential point of the tested circuit.

(7) The combination of the voltmeter pointer sheet and the voltmeter circular plate is rotated, the voltmeter pointer deflects when DC voltage is simulated, and then the measured value is simulated and read according to the selected measuring range and the effective digital rule.

(8) When DC voltage is measured by using 15V measuring range, the combination of the voltmeter pointer sheet and the voltmeter circular plate is rotated to make the deflection angle small, the deflection angle of the analog voltmeter pointer is small, and then the 3V measuring range is used for analysis and then the measuring error can be reduced.

(9) The method is characterized in that the measured value is read according to the effective digital rule, and is a key point and a difficult point, the combination of the voltmeter pointer and the voltmeter circular plate is required to be rotated for many times, different deflection angles of the voltmeter pointer are simulated, and the measured value is read by students according to the measuring range and the effective digital rule, so that the students are skilled to master.

By utilizing the ammeter demonstrating board, the following teaching can be performed on junior middle school or high school students:

(1) The meaning of the symbol "-" on the right binding post of the ammeter; the meaning of the number "0.6" on the binding post in the ammeter; the meaning of the number "3" on the left binding post of the ammeter.

(2) The full bias current on the dial of the ammeter is 0.6A and 3A; if a measuring range of 0.6A is selected, the measured value (the indicated value is the measured value) is read according to the scale with the full bias current of 0.6A, and if a measuring range of 3A is selected, the measured value is read according to the scale with the full bias current of 3A.

(3) The direct current of the measured circuit is estimated to be about 0.9A, the direct current of the measured circuit is measured, which measuring range should be selected by the ammeter, which two binding posts should be selected, and which scale should be selected to read the measured value.

(4) The direct current of the measured circuit is estimated to be about 0.2A, the direct current of the measured circuit is measured, which measuring range should be selected by the ammeter is analyzed, which two binding posts should be selected, and which scale should be selected to read the measured value.

(5) The ammeter is connected with the circuit of the measured current in series.

(6) If the direct current is measured in a measuring range of 0.6A, a circuit of the measured current is disconnected, two ends of one wire are simulated to be connected with one end of a disconnection part of a binding post in the ammeter and the measured circuit respectively, two ends of the other wire are simulated to be connected with the other end of the disconnection part of a right binding post of the ammeter and the measured circuit respectively, and the direct current is ensured to flow into the ammeter from the binding post in the ammeter and flow out from the right binding post of the ammeter; if the 3A measuring range is selected to measure direct current, a circuit of the measured current is disconnected, two ends of one wire are simulated to be connected with one end of a disconnection part of the ammeter left binding post and the measured circuit respectively, two ends of the other wire are simulated to be connected with the other end of a disconnection part of the ammeter right binding post and the measured circuit respectively, and direct current is ensured to flow into the ammeter from the ammeter left binding post and flow out from the ammeter right binding post.

(7) And rotating the combination of the ammeter pointer sheet and the ammeter circular plate, simulating the ammeter pointer deflection during DC current test, and then simulating and reading the measured value according to the selected measuring range and the effective numerical rule.

(8) When 3A measuring range is used for measuring direct current, the combined body of the ammeter pointer sheet and the ammeter circular plate is rotated to make the deflection angle small, the deflection angle of the ammeter pointer is simulated to be small, then the analysis is changed to 0.6A measuring range for retesting, and the measuring error can be reduced.

(9) The reading of the measured value according to the effective digital rule is important and difficult, and the combination of the ammeter pointer sheet and the ammeter circular plate is required to be rotated for multiple times to simulate different deflection angles of the ammeter pointer, so that students can read the measured value successively according to the measuring range and the effective digital rule for skilled mastering.

After the structure is adopted, the universal meter demonstrating board or the voltmeter demonstrating board or the ampere meter demonstrating board is a rectangular light board, so that the teacher can conveniently carry without effort, and the labor intensity of the teacher is reduced.

After the structure is adopted, the front image of the universal meter drawn on the universal meter teaching baseplate is far larger than the front image of the universal meter, and the front image of the universal meter is much clearer than the universal meter lifted by a teacher on a platform, and even though the universal meter teaching baseplate is a small component such as a pointer of the universal meter, students behind a sitting classroom can see clearly. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

After the structure is adopted, a teacher teaches the use of the universal meter, students receive both auditory stimulus and visual stimulus by means of the cooperation of the universal meter teaching board, and the two stimulus are mutually cooperated to sense deeply. Vivid image situation, more interest of students, higher learning enthusiasm, more thorough understanding and more firm memory. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

After adopting such structure, teacher's operation universal meter demonstrating board, movable component can be quiet, sound and explanation cooperation just like the hand and foot is cooperated appropriately, and teacher's instruction and operation promote mutually and complement each other, not only student welcome, and the teacher has also alleviateed intensity of labour. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

By adopting the structure, the pointer of the universal meter on the universal meter demonstration board can deflect slowly as required, so that students observe carefully and slightly, thinking is sufficient, and the impression is profound. The pointer deflection of the multimeter on the multimeter is quick and quick, the visual response of the student cannot be kept up, the students cannot observe in detail, and the impression is light. From the sense effect, the universal meter demonstrating board is better than the universal meter. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

By adopting the structure, the multimeter pointer, the mechanical zeroing knob, the ohmic zeroing knob and the range selection switch on the multimeter teaching board can rotate like the multimeter. The red pen and the black pen can be respectively inserted into a "+" jack and a "+" jack on a universal meter teaching board like the universal meter. In the operation process, students can see clearly and have a profound impression. The patterns of the same components on the wall chart of the universal meter are all the time, so that students feel boring and tasteless, and the interest of the students is not stimulated. From the teaching effect, the multimeter demonstrating board is far superior to the multimeter showing wall map. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

By adopting the structure, a teacher hangs the universal meter teaching board on the blackboard, the teaching can be started within 3 seconds, the teaching board does not need to be started, the teaching board does not need to be preheated, computer assistance and curtain hanging, courseware making and shooting, students do not need to wait for urgency, and the blackboard cannot be covered in a large area. Compared with the multimedia teaching aid, the universal meter teaching board is time-saving and trouble-saving, the classroom teaching time can be fully utilized, the teaching efficiency is greatly improved, and the labor intensity of teachers is also reduced. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

After the structure is adopted, the manufacturing cost of the universal meter teaching board is very low, and more media teaching aids of the universal meter teaching board are far superior from the aspects of popularization difficulty, time required by popularization and the number of beneficiaries. The same effect can be produced by teaching using a voltmeter teaching board or an ammeter teaching board.

After the structure is adopted, as the teacher prevents the possible errors of using the universal meter, the voltmeter or the ammeter by virtue of the ammeter demonstrating board in advance, the experiment errors of the students are greatly reduced, the teacher does not worry about burning the ammeter, worry about crashing the ammeter pointer, worry about using the wrong measuring range of the students, and worry about coping with the wrong measuring range of the students, the experiment process of the students is well ordered, the experiment progress is rapid, the obtained experiment data is accurate, and the labor intensity of the teacher is greatly reduced.

Drawings

The following describes the embodiments of the present invention in further detail with reference to the drawings.

FIG. 1 is a schematic front view of a multimeter teach pendant.

Fig. 2 is a schematic front view of a voltmeter teach pendant.

Fig. 3 is a schematic front view of an ammeter demonstrating board.

Detailed Description

As shown in fig. 1 to 3, the ammeter teaching board includes three independent and unstructured multimeter teaching boards 1, a voltmeter teaching board 8 and an ammeter teaching board 14.

As shown in fig. 1, the multimeter teaching board 1 includes a multimeter teaching board 1a, and a multimeter front image and a pen drawn on a white outer surface of the multimeter teaching board 1 a.

The universal meter teaching base plate 1a is a rectangular light plate and is made of soft magnetic materials, and the area of the outer surface of the universal meter teaching base plate is far larger than that of the front surface of the universal meter; the drawn multimeter front image is much larger than the multimeter front image.

On the drawn front image of the multimeter, the pattern of the mechanical zeroing screw 2 is replaced by a mechanical zeroing circular plate 2b which can rotate around a mechanical zeroing shaft 2a but cannot move along the axial direction, and the mechanical zeroing shaft 2a is fixedly connected to the corresponding position of the multimeter teaching baseplate 1 a.

On the drawn front image of the multimeter, the graph of the ohmic zeroing knob 3 is replaced by an ohmic zeroing circular plate 3b which can rotate around an ohmic zeroing shaft 3a but cannot move along the axial direction, and the ohmic zeroing shaft 3a is fixedly connected to a corresponding position of the multimeter teaching baseplate 1 a.

On the drawn front image of the multimeter, the graph of the range selection switch 4 is replaced by a rotary disk 4b which can rotate around a range selection shaft 4a but can not move along the axial direction, the shape of the rotary disk 4b is the same as the shape of the real object of the range selection switch 4, and the range selection shaft 4a is fixedly connected to the corresponding position of the multimeter teaching baseplate 1 a.

The drawn multimeter front image is replaced by a movable short straight thin rod 5a with magnetism on the graph of the multimeter pointer 5. The thin rod 5a can be adsorbed on a dial of the drawn front image of the multimeter, so that a teacher can conveniently change the position of the thin rod 5a relative to the dial, and deflection of the pointer 5 of the multimeter is simulated.

On the drawn front image of the multimeter, the figure of the "+" jack 6 is a real round hole penetrating through the multimeter teaching baseplate 1a in the corresponding position.

On the drawn front image of the multimeter, the figure of the "-" jack 7 is a true circular hole penetrating the multimeter teaching baseplate 1a in the corresponding position.

The meter pen consists of a red meter pen and a black meter pen. The red gauge pen and the black gauge pen can be respectively inserted into a "+" jack 6 and a "-" jack 7 on the universal meter teaching board 1.

As shown in fig. 2, the voltmeter teach pendant 8 comprises a voltmeter teach pendant 8a and a voltmeter front image drawn on the white outer surface of the voltmeter teach pendant 8 a.

The voltmeter teaches that the base plate 8a is a rectangular lightweight plate with an outer surface having an area substantially larger than the area of the front surface of the voltmeter. The front image of the drawn voltmeter is much larger than the front image of the voltmeter.

The graphic of the voltmeter pointer 9 on the drawn voltmeter front image is replaced with a combination of a rotatable voltmeter pointer piece 9a and a voltmeter circular plate 9 b. The voltmeter pointer 9a is a rigid strip-shaped narrow piece, and the front end of the piece is pointed. The outer diameter of the voltmeter circular plate 9b is far smaller than the length of the voltmeter pointer sheet 9a, a circular hole is formed in the center of the voltmeter pointer sheet 9a and is positioned at the rear end of the voltmeter pointer sheet 9a, a screw 10 penetrates through the upper circular hole to install the voltmeter pointer sheet on the voltmeter teaching baseplate 8a, and the installation point is positioned on the circle center of the scale disc circular arc on the drawn voltmeter front image. The voltmeter pointer 9a is pushed by hand to rotate around the axis of the screw 10 along the outer surface of the voltmeter pointer plate 8a, thereby simulating the deflection of the voltmeter pointer 9, and the static friction force can keep the voltmeter pointer 9 relatively static when the hand is separated from the voltmeter pointer.

On the front image of the depicted voltmeter, the right binding post 11 of the voltmeter is a circle, and the "-" sign is marked on the circle.

On the front image of the depicted voltmeter, the posts 12 in the voltmeter are circles, on which the number "3" is marked.

On the front image of the depicted voltmeter, the left binding post 13 of the voltmeter is a circle, on which the number "15" is marked.

As shown in fig. 3, the ammeter teaching panel 14 includes an ammeter teaching substrate 14a and an ammeter front image drawn on the white outer surface of the ammeter teaching substrate 14 a.

The ammeter teaching base plate 14a is a rectangular light plate, and the area of the outer surface of the ammeter teaching base plate is far larger than that of the front surface of the ammeter; the drawn front image of the ammeter is much larger than the front image of the ammeter.

The graphic of the ammeter pointer 15 on the drawn ammeter front image is replaced with a combination of rotatable ammeter pointer piece 15a and ammeter circular plate 15 b. The ammeter indicating piece 15a is a rigid strip-shaped narrow piece, and the front end thereof is pointed. The outer diameter of the ammeter circular plate 15b is far smaller than the length of the ammeter pointer piece 15a, a round hole is formed in the center of the ammeter pointer piece 15a and is positioned at the rear end of the ammeter pointer piece 15a, a screw 10 penetrates through the round hole to mount the ammeter pointer piece on the ammeter teaching baseplate 15a, and the mounting point is positioned on the circle center of the scale disc arc line on the ammeter front image. The ammeter pointer piece 15a is pushed by hand to rotate about the axis of the screw 10 along the outer surface of the ammeter pointer plate 14a, thereby simulating deflection of the ammeter pointer 15, and static friction force can keep it relatively stationary when the hand is disengaged therefrom.

On the drawn ammeter front image, the ammeter right terminal 16 is a circle, and the "-" sign is marked on the circle.

On the drawn ammeter front image, the binding post 17 in the ammeter is a circle, and the numeral "0.6" is marked on the circle.

On the drawn ammeter front image, the ammeter left terminal 18 is a circle, and the numeral "3" is marked on the circle.

As shown in fig. 1, with this multimeter demonstrating board 1, the following teaching can be performed for high school students:

first, introduce universal meter

(1) The function of a multimeter is described.

(3) The student is guided to observe the relative positions of the resistor scale and the voltage and current sharing scale, the distribution condition of scale marks on the resistor scale and the voltage and current sharing scale is that the 0 scale mark on the resistor scale is positioned at the leftmost side (the right side of an observer) of the resistor scale, and the 0 scale mark on the voltage and current sharing scale is positioned at the rightmost side of the sharing scale. And guiding students to compare the uniformity and arrangement sequence of the scale values on the resistor scale, the voltage and current combined scale.

(4) The physical meaning of the following symbols on a multimeter is taught:

second, general use method of universal meter is taught

(5) The mechanical zeroing circular plate 2b is rotated, the thin rod 5a is moved to the 0 scale mark of the voltage and current combined scale, and the mechanical zeroing screw 2 is adjusted in a simulation mode, so that the pointer 5 of the universal meter is zeroed.

(6) Analog red gauge jack "+" jack 6, black gauge jack "-" jack 7.

Third, universal meter measuring resistor

(7) The rotary disk 4b is rotated to simulate the rotary range selection switch 4 and put it in a proper range of the resistance gear.

(8) The resistance measurement is to be firstly ohm zeroed: the red meter pen and the black meter pen are in short circuit, the ohm zeroing circular plate 3b is rotated, the ohm zeroing knob 3 is simulated to be rotated, the thin rod 5a is moved to the leftmost side (the right side of an observer) of the resistor scale, the pointer 5 of the simulated multimeter is deflected to the scale line 0, and the operation is ohm zeroing; then the red meter pen and the black meter pen are separated, the thin rod 5a is moved to the rightmost side of the resistance scale, and after the red meter pen and the black meter pen are simulated to be separated, the pointer 5 of the universal meter returns to the rightmost side of the resistance scale.

(9) Measuring resistance: the red meter pen and the black meter pen are respectively overlapped with two ends of the measured resistor, a human body cannot be connected with the measured resistor in parallel, the thin rod 5a is moved to the middle of the resistor scale, the pointer 5 of the analog multimeter deflects when the resistor is measured, then the indicated value of the pointer 5 of the analog multimeter is simulated and read, and then the measured value is calculated:

Measured value = instruction value x magnification

(10) And the whole process is coherent to simulate the resistance measurement.

(11) The red meter pen and the black meter pen are respectively overlapped with the two ends of the measured resistor, so that the thin rod 5a stays near the rightmost side of the resistor scale or near the 0 scale mark, the deflection angle of the analog multimeter pointer 5 is small or large, and in order to reduce measurement errors, how to change the resistor measuring range for retesting is taught.

(13) The reason why multimeter pointer 5 will deflect when measuring the resistance. A battery is arranged in the original universal meter, and the battery is connected into a circuit when the equivalent range selection switch 4 is placed in a resistance gear. The battery is idle when the range selector switch 4 is placed in other gear positions.

Fourth, universal meter measures DC voltage

(14) The rotary disk 4b is rotated to direct the rotary disk to the direct-current voltage gear, and the analog rotary range selection switch 4 is placed in the direct-current voltage gear.

(15) The selection of analog dc voltage ranges is taught while.

(16) The universal meter is connected with the tested circuit in parallel for measuring the direct current voltage. Then the analog red pointer contacts with the high potential point of the tested circuit, the black pointer contacts with the low potential point of the tested circuit, the thin rod 5a is moved to stay in the middle of the dial, and the deflection of the multimeter pointer 5 during the direct current voltage measurement is simulated. The black pointer can be simulated to be contacted with a high potential point of a measured circuit, the red pointer is simulated to be contacted with a low potential point of the measured circuit, the thin rod 5a is contacted with the right side of the dial, and the universal meter pointer 5 is simulated to collide with a right side watch case, so that the universal meter pointer 5 can be caused to collide and bend, and the impression of students is deepened.

(17) Moving the thin rod 5a to stay in the middle of the dial, and deflecting the pointer 5 of the universal meter when the direct-current voltage is simulated and tested; the indication of multimeter pointer 5 is then read in a simulated manner and the measured value is calculated:

(18) The thin rod 5a is stopped near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, the deflection angle of the analog multimeter pointer 5 is too small or too large, and in order to reduce measurement errors, the method is used for explaining how to change the direct current voltage range and retest.

Fifth, universal meter measures AC voltage

(19) The rotary disk 4b is rotated to be directed to the ac voltage gear, and the analog rotary range selection switch 4 is placed in the ac voltage gear.

(20) The selection of analog ac voltage ranges is taught while.

(21) The universal meter is connected with the tested circuit in parallel for testing the alternating voltage. The analog red meter pen and the black meter pen are randomly overlapped with two ends of the tested circuit respectively, and the difference between the analog red meter pen and the black meter pen and the tested direct current voltage is pointed out.

(22) The thin rod 5a is moved to stay in the middle of the dial, and the multimeter pointer 5 deflects when the alternating voltage is simulated and tested. The indication of the multimeter pointer 5 is then read in a simulation and the measured value is calculated:

(23) The thin rod 5a is stopped near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, and the deflection angle of the analog multimeter pointer 5 is too small or too large, so that the measurement error is reduced, and how to change the AC voltage range for retesting is taught.

Six, universal meter measures direct current

(24) The rotary disk 4b is rotated to direct the rotary disk to a direct current gear, and the analog rotary range selection switch 4 is placed in the direct current gear.

(25) The selection of analog dc current ranges is taught while.

(26) The universal meter is connected with the tested circuit in series to measure the direct current. The tested circuit is disconnected, the analog red meter pen and the black meter pen are respectively overlapped with the two ends of the disconnected part, the important point is that direct current flows into the universal meter from the red meter pen and flows out from the black meter pen, then the thin rod 5a is moved to stay in the middle of the dial, and the pointer 5 of the universal meter deflects when the direct current is measured in an analog mode. Intentional misconnections may be made if desired: direct current flows into the multimeter from the black meter pen and flows out from the red meter pen, so that the thin rod 5a contacts with the right side of the dial, and the pointer 5 of the multimeter is simulated to collide with the watch case on the right side, so that the pointer 5 of the multimeter can be caused to collide and bend, and the impression of students is deepened. Even the universal meter can be intentionally simulated to be connected with the tested circuit in parallel, so that the meter head of the universal meter is burnt out, and the students can inscribe the heart.

(27) The thin rod 5a is moved to stay in the middle of the dial, and the multimeter pointer 5 deflects when the direct current is simulated and tested. The indication of the multimeter pointer 5 is then read in a simulation and the measured value is calculated:

(28) The thin rod 5a is stopped near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, the deflection angle of the analog multimeter pointer 5 is too small or too large, and in order to reduce measurement errors, the method is used for explaining how to change the direct current measuring range and retest.

(29) When the multimeter is not in use for a short period, the rotary disk 4b is rotated to point to the maximum range of the alternating voltage gear, and the range selection switch 4 is simulated to be placed in the maximum range of the alternating voltage gear, and the reason is described.

(30) When the multimeter is not in use for a long time, the battery in the multimeter is taken out in addition to the maximum range of the alternating voltage range of the range selection switch 4, and the reason is described.

As shown in fig. 2, with the voltmeter teaching board 8, the following teaching can be performed for junior middle school or high school students:

(1) The meaning of the symbol "-" on the right post 11 of the voltmeter. The meaning of the number "3" on the terminal 12 in the voltmeter. The meaning of the number "15" on the left post 13 of the voltmeter.

(2) The full bias voltage on the scale of the voltmeter is 3V and 15V. If a 3V measuring range is selected, the measured value (the indicated value is the measured value) is read according to the scale with the full bias voltage of 3V, and if a 15V measuring range is selected, the measured value is read according to the scale with the full bias voltage of 15V.

(5) The voltmeter is connected in parallel with the measured voltage circuit.

(6) If 3V measuring range is selected to test direct current voltage, two ends of one wire are respectively connected with a binding post 12 in the voltmeter and a high potential point of a tested circuit, and two ends of the other wire are respectively connected with a right binding post 11 of the voltmeter and a low potential point of the tested circuit. If a 15V measuring range is selected, two ends of one wire for simulation are respectively connected with the left binding post 13 of the voltmeter and a high potential point of a tested circuit, and two ends of the other wire are respectively connected with the right binding post 11 of the voltmeter and a low potential point of the tested circuit.

(7) The combination of the voltmeter pointer 9a and the voltmeter circular plate 9b is rotated, the voltmeter pointer 9 deflects when the DC voltage is simulated, and then the measured value is simulated and read according to the selected measuring range and the effective digital rule.

(8) When measuring DC voltage with 15V measuring range, the combination of the voltmeter pointer 9a and the voltmeter circular plate 9b is rotated to make the deflection angle small, the deflection angle of the analog voltmeter pointer 9 is small, and then the 3V measuring range is used for analysis and the measuring error can be reduced.

(9) Reading the measured value according to the effective digital rule is important and difficult, and the combination of the voltmeter pointer 9a and the voltmeter circular plate 9b is required to be rotated for many times to simulate different deflection angles of the voltmeter pointer 9, so that students can read the measured value successively according to the measuring range and the effective digital rule to acquire proficiency.

As shown in fig. 3, with the ammeter teaching board 14, the following teaching can be performed for junior middle school or high school students:

(1) The symbol "-" on the right hand post 16 of the ammeter. The sense of the number "0.6" on the post 17 in the ammeter. The sense of the number "3" on the left post 18 of the ammeter.

(6) If the measuring range of 0.6A is selected to measure direct current, a circuit of the measured current is disconnected, two ends of one wire are simulated to be connected with one end of a disconnection part of the binding post 17 in the ammeter and the measured circuit respectively, two ends of the other wire are simulated to be connected with the other end of the disconnection part of the right binding post 16 in the ammeter and the measured circuit respectively, and direct current is ensured to flow into the ammeter from the binding post 17 in the ammeter and flow out from the right binding post 16 in the ammeter. If the 3A measuring range is selected to measure the direct current, the circuit of the measured current is disconnected, two ends of one wire are simulated to be connected with one end of the broken position of the ammeter left binding post 18 and the measured circuit respectively, two ends of the other wire are simulated to be connected with the other end of the broken position of the ammeter right binding post 16 and the measured circuit respectively, and the direct current is ensured to flow into the ammeter from the ammeter left binding post 18 and flow out from the ammeter right binding post 16.

(7) The combination of ammeter pointer 15a and ammeter circular plate 15b is rotated, the ammeter pointer 15 deflects when the DC current is simulated and the measurement value is then simulated and read according to the selected measuring range and according to the effective digital rule.

(8) When measuring DC current with 3A measuring range, the combined body of the ammeter pointer sheet 15a and the ammeter circular plate 15b is rotated to make the deflection angle small, the deflection angle of the ammeter pointer 15 is simulated to be small, then the analysis is changed to 0.6A measuring range for retesting, and the measuring error can be reduced.

(9) Reading the measured value according to the effective digital rule is important and difficult, and the combination of the ammeter pointer sheet 15a and the ammeter circular plate 15b is required to be rotated for multiple times to simulate different deflection angles of the ammeter pointer 15, so that students can read the measured value successively according to the measuring range and the effective digital rule for skilled mastering.

The embodiments of the present invention are described in detail above with reference to the drawings. The present invention is not limited to the above-described embodiments, and various changes may be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present invention. Various changes may be made without departing from the spirit of the invention and still fall within the scope of the invention.

Claims

1. An ammeter demonstrating board, its characterized in that:

the ammeter demonstrating board is a teaching aid for a junior middle school or high school physical teacher to teach students an ammeter using method in classroom teaching or extracurricular coaching;

the ammeter demonstrating board comprises three independent and unstructured multimeter demonstrating boards (1), a voltmeter demonstrating board (8) and an ammeter demonstrating board (14);

the universal meter teaching board (1) comprises a universal meter teaching base board (1 a), and a universal meter front image and a meter pen which are drawn on the white outer surface of the universal meter teaching base board (1 a);

the universal meter teaching base plate (1 a) is a rectangular light plate and is made of soft magnetic materials, and the area of the outer surface of the universal meter teaching base plate is far larger than that of the front surface of the universal meter; the drawn front image of the universal meter is far larger than the front image of the universal meter;

on the drawn front image of the universal meter, the graph of the mechanical zeroing screw (2) is replaced by a mechanical zeroing circular plate (2 b) which can rotate around a mechanical zeroing shaft (2 a) but cannot move along the axial direction, and the mechanical zeroing shaft (2 a) is fixedly connected to the corresponding position of the universal meter teaching bottom plate (1 a);

on the drawn front image of the universal meter, the graph of the ohm zeroing knob (3) is replaced by an ohm zeroing circular plate (3 b) which can rotate around an ohm zeroing shaft (3 a) but cannot move along the axial direction, and the ohm zeroing shaft (3 a) is fixedly connected to the corresponding position of the universal meter teaching bottom plate (1 a);

On the drawn front image of the universal meter, a graph of a range selection switch (4) is replaced by a rotary table (4 b) which can rotate around a range selection shaft (4 a) but cannot move along the axial direction, the shape of the rotary table (4 b) is the same as the shape of a real object of the range selection switch (4), and the range selection shaft (4 a) is fixedly connected to a corresponding position of a universal meter teaching baseplate (1 a);

on the drawn front image of the multimeter, the graph of the multimeter pointer (5) is replaced by a movable short straight thin rod (5 a) with magnetism; the thin rod (5 a) can be adsorbed on a dial of the drawn front image of the multimeter, so that a teacher can conveniently change the position of the thin rod (5 a) relative to the dial, and deflection of the pointer (5) of the multimeter is simulated;

on the drawn front image of the universal meter, the figure of the "+" jack (6) is a real round hole penetrating through the universal meter teaching baseplate (1 a) at the corresponding position;

on the drawn front image of the multimeter, the figure of the "-" jack (7) is a real round hole penetrating through the multimeter teaching baseplate (1 a) at the corresponding position;

the meter pen consists of a red meter pen and a black meter pen; the red gauge pen and the black gauge pen can be respectively inserted into a "+" jack (6) and a "-" jack (7) on the universal meter teaching board (1);

The voltmeter teaching board (8) comprises a voltmeter front image drawn on the white outer surface of the voltmeter teaching board (8 a) and the voltmeter teaching board (8 a);

the voltmeter teaching base plate (8 a) is a rectangular light plate, and the area of the outer surface of the base plate is far larger than that of the front surface of the voltmeter; the front image of the drawn voltmeter is far larger than the front image of the voltmeter;

the figure of the voltmeter pointer (9) is replaced by a rotatable voltmeter pointer sheet (9 a) and voltmeter circular plate (9 b) combination on the drawn voltmeter front image; the voltmeter pointer sheet (9 a) is a rigid strip-shaped narrow sheet, and the front end of the voltmeter pointer sheet is pointed; the outer diameter of the voltmeter circular plate (9 b) is far smaller than the length of the voltmeter pointer sheet (9 a), a circular hole is formed in the center of the voltmeter pointer sheet (9 a), the circular hole is formed in the rear end of the voltmeter pointer sheet, a screw (10) penetrates through the upper circular hole of the circular hole to install the circular hole on the voltmeter pointer sheet on the voltmeter teaching base plate (8 a), and the installation point is located on the center of a scale arc line on the drawn voltmeter front image; pushing the voltmeter pointer sheet (9 a) by hand to rotate around the axis of the screw (10) along the outer surface of the voltmeter pointer base plate (8 a), so as to simulate the deflection of the voltmeter pointer (9), and keeping the voltmeter pointer relatively static by static friction force when the hand is separated from the voltmeter pointer sheet;

On the drawn front image of the voltmeter, a right binding post (11) of the voltmeter is a circle, and a "-" sign is marked on the circle;

on the drawn front image of the voltmeter, the binding posts (12) in the voltmeter are circles, and the numbers '3' are marked on the circles;

on the drawn front image of the voltmeter, the left binding post (13) of the voltmeter is a circle, and the number '15' is marked on the circle;

the ammeter teaching board (14) comprises an ammeter front image drawn on the white outer surface of the ammeter teaching board (14 a) and the ammeter teaching board (14 a);

the ammeter teaching base plate (14 a) is a rectangular light plate, and the area of the outer surface of the ammeter teaching base plate is far larger than that of the front surface of the ammeter; the drawn ammeter front image is far larger than the ammeter front image;

the graphic of the ammeter pointer (15) is replaced by a rotatable ammeter pointer sheet (15 a) and ammeter circular plate (15 b) combination on the drawn ammeter front image; the ammeter pointer sheet (15 a) is a rigid strip-shaped narrow sheet, and the front end of the ammeter pointer sheet is pointed; the ammeter circular plate (15 b) is far smaller than the length of the ammeter pointer sheet (15 a) in outer diameter, a circular hole is formed in the center of the ammeter pointer sheet (15 a), the ammeter pointer sheet is positioned at the rear end of the ammeter pointer sheet (15 a), a screw (10) penetrates through the circular hole to install the ammeter pointer sheet on the ammeter teaching baseplate (14 a), and the installation point is positioned at the center of a scale disc circular arc on the ammeter front image; pushing the ammeter pointer piece (15 a) by hand to rotate around the axis of the screw (10) along the outer surface of the ammeter pointer base plate (14 a), so as to simulate deflection of the ammeter pointer (15), and keeping the ammeter pointer piece relatively static by static friction force when the hand is separated from the ammeter pointer piece;

On the drawn ammeter front image, an ammeter right binding post (16) is a circle, and a "-" sign is marked on the circle;

on the drawn ammeter front image, a binding post (17) in the ammeter is a circle, and the circle is marked with a number of 0.6;

on the drawn ammeter front image, the ammeter left binding post (18) is a circle, and the number '3' is marked on the circle;

2. An electricity meter demonstrating board according to claim 1, wherein:

by utilizing the universal meter demonstrating board (1), the following teaching can be performed on high school students:

first, introduce universal meter

(1) Introducing the function of the universal meter;

(2) The names and the functions of all movable components on the universal meter are taught;

(3) Guiding students to observe the relative positions of the resistor scale and the voltage and current combined scale, wherein the distribution condition of scale marks on the resistor scale and the voltage and current combined scale is that a 0 scale mark on the resistor scale is positioned at the leftmost side (the right side of an observer) of the resistor scale and a 0 scale mark on the voltage and current combined scale is positioned at the rightmost side of the combined scale; guiding students to compare the uniformity and arrangement sequence of scale values on the resistor scale and the voltage and current combined scale;

(4) The physical meaning of the following symbols on a multimeter is taught:

second, general use method of universal meter is taught

(5) Rotating a mechanical zeroing circular plate (2 b), moving a thin rod (5 a) to a 0 scale mark of a voltage and current shared scale, and simulating and adjusting a mechanical zeroing screw (2) to zero a pointer (5) of the universal meter;

(6) Simulating a red meter pen holder "+" jack (6), and a black meter pen holder "-" jack (7);

third, universal meter measuring resistor

(7) A rotary turntable (4 b) for simulating the rotary range selection switch (4) and placing the rotary range selection switch in a proper range of the resistance gear;

(8) The resistance measurement is to be firstly ohm zeroed: the red meter pen and the black meter pen are in short circuit, the ohm zeroing circular plate (3 b) is rotated, the ohm zeroing knob (3) is simulated to be rotated, the thin rod (5 a) is moved to the leftmost side of the resistance scale (the right side of an observer), the pointer (5) of the simulated multimeter is deflected to the scale mark of 0, and the operation is ohm zeroing; then the red meter pen and the black meter pen are separated, the thin rod (5 a) is moved to the rightmost side of the resistance scale, and after the red meter pen and the black meter pen are simulated to be separated, the pointer (5) of the universal meter returns to the rightmost side of the resistance scale;

(9) Measuring resistance: the red meter pen and the black meter pen are respectively overlapped with two ends of a measured resistor, a human body cannot be connected with the measured resistor in parallel, a thin rod (5 a) is moved to the middle of a resistor scale, a pointer (5) of a multimeter is simulated to deflect when the resistor is measured, then an indication value of the pointer (5) of the multimeter is simulated to be read, and then a measured value is calculated:

Measured value = instruction value x magnification

(10) The whole course is coherent to simulate the resistance measurement;

(11) The red meter pen and the black meter pen are respectively overlapped with two ends of a measured resistor, so that the thin rod (5 a) stays near the rightmost side of a resistor scale or near a 0 scale mark, the deflection angle of the analog multimeter pointer (5) is small or large, and in order to reduce measurement errors, how to change the resistor measuring range for retesting is explained;

(12) Emphasis is placed on the fact that ohmic zero setting is still needed first for changing the resistance range and then measuring the resistance;

(13) The reason why the multimeter pointer (5) will deflect when measuring the resistance; a battery is arranged in the original universal meter, and the battery is connected into a circuit when a range selection switch (4) is arranged in a resistance gear; when the range selection switch (4) is placed in other gears, the battery is idle and not used;

fourth, universal meter measures DC voltage

(14) Rotating the rotary table (4 b) to enable the rotary table to point to a direct-current voltage gear, and arranging the analog rotating range selection switch (4) in the direct-current voltage gear;

(15) Teaching selection of analog DC voltage range;

(16) The universal meter is connected with the tested circuit in parallel; then simulating the contact of a red meter pen with a high potential point of a tested circuit, the contact of the black meter pen with a low potential point of the tested circuit, moving a thin rod (5 a) to stay in the middle of a dial, and simulating the deflection of a universal meter pointer (5) during the direct current voltage measurement; the black meter pen can be simulated to be contacted with a high potential point of a tested circuit, the red meter pen is simulated to be contacted with a low potential point of the tested circuit, the thin rod (5 a) is contacted with the right side of the dial, and the universal meter pointer (5) is simulated to collide with a right side watchcase, so that the universal meter pointer (5) can be caused to collide and bend, and the impression of students is deepened;

(17) Moving the thin rod (5 a) to stay in the middle of the dial, and deflecting the pointer (5) of the universal meter when the direct-current voltage is simulated and tested; then the indication value of the multimeter pointer (5) is read in a simulation manner, and the measured value is calculated:

(18) The thin rod (5 a) is kept near the rightmost side (left side of an observer) or the leftmost side of the voltage and current sharing scale, the deflection angle of the analog multimeter pointer (5) is too small or too large, and in order to reduce measurement errors, how to change the direct-current voltage range for retesting is taught;

fifth, universal meter measures AC voltage

(19) Rotating the rotary table (4 b) to enable the rotary table to point to the alternating voltage gear, and arranging the analog rotating range selection switch (4) in the alternating voltage gear;

(20) Teaching selection of analog ac voltage range;

(21) The universal meter is connected with the tested circuit in parallel; the analog red meter pen and the black meter pen are overlapped with two ends of the tested circuit at will, and the difference between the analog red meter pen and the black meter pen and the tested direct current voltage is pointed out;

(22) Moving the thin rod (5 a) to stay in the middle of the dial, and deflecting the pointer (5) of the universal meter when the alternating voltage is simulated and tested; then the indication value of the multimeter pointer (5) is simulated and the measured value is calculated:

(23) The thin rod (5 a) is kept near the rightmost side (left side of an observer) or the leftmost side of the voltage and current combined scale, the deflection angle of the analog multimeter pointer (5) is too small or too large, and in order to reduce measurement errors, how to change the AC voltage range for retesting is taught;

Six, universal meter measures direct current

(24) Rotating the rotary table (4 b) to lead the rotary table to point to a direct current gear, and arranging the analog rotating range selection switch (4) in the direct current gear;

(25) Teaching the selection of analog DC current range;

(26) The universal meter is connected with the tested circuit in series; disconnecting the tested circuit, overlapping the analog red meter pen and the black meter pen with two ends of the disconnected part respectively, focusing on the fact that direct current flows into the universal meter from the red meter pen and flows out from the black meter pen, then moving the thin rod (5 a) to stay in the middle of the dial, and simulating deflection of the pointer (5) of the universal meter when the direct current is tested; intentional misconnections may be made if desired: direct current flows into the multimeter from the black meter pen and flows out from the red meter pen, the thin rod (5 a) is contacted with the right side of the dial, and the pointer (5) of the multimeter is simulated to collide with the watch case on the right side, so that the pointer (5) of the multimeter can be caused to collide and bend, and the impression of students is deepened; even the universal meter can be intentionally simulated to be connected with the tested circuit in parallel, so that the meter head of the universal meter is burnt out, and the students can inscribe the bone and the heart;

(27) Moving the thin rod (5 a) to stay in the middle of the dial, and simulating deflection of the pointer (5) of the universal meter when testing direct current; then the indication value of the multimeter pointer (5) is simulated and the measured value is calculated:

(28) The thin rod (5 a) is kept near the rightmost side (left side of an observer) or the leftmost side of the voltage and current sharing scale, the deflection angle of the analog multimeter pointer (5) is too small or too large, and in order to reduce measurement errors, how to change the direct current measuring range for retesting is explained;

(29) When the universal meter is not used for a short time, the rotary table (4 b) is rotated to point to the maximum range gear of the alternating voltage gear, and the range selection switch (4) is simulated to be arranged at the maximum range gear of the alternating voltage gear, so that the reason is explained;

(30) When the multimeter is not used for a long time, the range selection switch (4) is arranged at the maximum range of the alternating voltage range, and the battery in the multimeter is taken out, so that the reason is described.

3. An electricity meter demonstrating board according to claim 1, wherein:

by utilizing the voltmeter teaching board (8), the following teaching can be performed on junior middle school or high school students:

(1) The meaning of the symbol "-" on the right binding post (11) of the voltmeter; the meaning of the number "3" on the binding post (12) in the voltmeter; the meaning of the number 15 on the left binding post 13 of the voltmeter;

(2) The full bias voltage on the dial of the voltmeter is 3V and 15V; if a 3V measuring range is selected, a measured value (an indicated value is a measured value) is read according to a scale with the full bias voltage of 3V, and if a 15V measuring range is selected, the measured value is read according to the scale with the full bias voltage of 15V;

(3) Estimating the direct current voltage of the tested circuit to be about 8V, measuring the direct current voltage of the tested circuit, analyzing which measuring range should be selected by the voltmeter, which two binding posts should be selected, and which scale should be selected to read the measured value;

(4) Measuring the voltage of the dry battery by using a voltmeter, analyzing which measuring range should be selected by the voltmeter, which two binding posts should be selected, and which scale should be selected to read the measured value;

(5) The voltmeter is connected with the tested voltage circuit in parallel;

(6) If 3V measuring range is selected to test direct current voltage, two ends of one wire are respectively connected with a binding post (12) in the voltmeter and a high potential point of a tested circuit, and two ends of the other wire are respectively connected with a right binding post (11) of the voltmeter and a low potential point of the tested circuit; if a 15V measuring range is selected, two ends of one wire for simulation are respectively connected with a left binding post (13) of the voltmeter and a high potential point of a tested circuit, and two ends of the other wire are respectively connected with a right binding post (11) of the voltmeter and a low potential point of the tested circuit;

(7) Rotating the combination of the voltmeter pointer sheet (9 a) and the voltmeter circular plate (9 b), simulating the deflection of the voltmeter pointer (9) when measuring direct current voltage, and then simulating and reading the measured value according to the selected measuring range and the effective digital rule;

(8) When the DC voltage is measured by using 15V measuring range, the combined body of the voltmeter pointer sheet (9 a) and the voltmeter circular plate (9 b) is rotated to make the deflection angle small, the deflection angle of the analog voltmeter pointer (9) is small, then the 3V measuring range is used for analysis, and the measuring error can be reduced;

(9) The reading of the measured value according to the effective digital rule is important and difficult, and the combination of the voltmeter pointer sheet (9 a) and the voltmeter circular plate (9 b) needs to be rotated for many times to simulate different deflection angles of the voltmeter pointer (9), so that students can read the measured value successively according to the measuring range and the effective digital rule to acquire proficiency.

4. An electricity meter demonstrating board according to claim 1, wherein:

by using the ammeter teaching board (14), the following teaching can be performed for junior middle school or high school students:

(1) The meaning of the symbol "-" on the right binding post (16) of the ammeter; the meaning of the number 0.6 on the binding post (17) in the ammeter; the meaning of the number 3 on the ammeter left binding post 18;

(2) The full bias current on the dial of the ammeter is 0.6A and 3A; if a measuring range of 0.6A is selected, a measured value (the indicated value is the measured value) is read according to a scale with the full bias current of 0.6A, and if a measuring range of 3A is selected, the measured value is read according to a scale with the full bias current of 3A;

(3) Estimating the direct current of the tested circuit to be about 0.9A, testing the direct current of the tested circuit, analyzing which measuring range should be selected by the ammeter, which two binding posts should be selected, and which scale should be selected to read the measured value;

(4) Estimating the direct current of the tested circuit to be about 0.2A, testing the direct current of the tested circuit, analyzing which measuring range should be selected by the ammeter, which two binding posts should be selected, and which scale should be selected to read the measured value;

(5) The ammeter is connected with the circuit of the tested current in series;

(6) If a 0.6A measuring range is selected to measure direct current, a circuit of the measured current is disconnected, two ends of one wire are simulated to be connected with a binding post (17) in an ammeter and one end of a disconnected part of the measured circuit respectively, two ends of the other wire are simulated to be connected with a right binding post (16) of the ammeter and the other end of the disconnected part of the measured circuit respectively, and direct current is ensured to flow into the ammeter from the binding post (17) in the ammeter and flow out from the right binding post (16) of the ammeter; if 3A measuring range is selected to measure direct current, a circuit of the measured current is disconnected, two ends of one wire are simulated to be connected with one end of a disconnection part of an ammeter left binding post (18) and the measured circuit respectively, two ends of the other wire are simulated to be connected with the other end of a disconnection part of an ammeter right binding post (16) and the measured circuit respectively, and direct current is ensured to flow into the ammeter from the ammeter left binding post (18) and flow out from the ammeter right binding post (16);

(7) Rotating the combination of the ammeter pointer sheet (15 a) and the ammeter circular plate (15 b), simulating deflection of the ammeter pointer (15) during DC test, and then simulating and reading measured values according to the selected measuring range and the effective digital rule;

(8) When the 3A measuring range is used for measuring direct current, the combined body of the ammeter pointer sheet (15 a) and the ammeter circular plate (15 b) is rotated to enable the deflection angle to be small, the deflection angle of the ammeter pointer (15) is simulated to be small, then the 0.6A measuring range is used for measuring again, and the measuring error can be reduced;

(9) The reading of the measured value according to the effective digital rule is important and difficult, and the combination of the ammeter pointer sheet (15 a) and the ammeter circular plate (15 b) needs to be rotated for multiple times to simulate different deflection angles of the ammeter pointer (15), so that students can read the measured value successively according to the measuring range and the effective digital rule to acquire proficiency.