CN204758700U - Adopt resistance to select separately teaching aid of measuring circuit - Google Patents

Abstract

The utility model discloses a teaching aid using a resistance sorting and measuring circuit, which comprises a power supply and a single-arm bridge circuit; the power supply supplies voltage to the single-arm bridge circuit, and the input end of the single-arm bridge circuit is connected Connected with a switch and a sliding rheostat, one arm of the single-arm bridge circuit is composed of a resistance box to form the first resistance (R1, R2), and the other arm is composed of a resistance bracket and a module resistance to form the second resistance (R3, R4) A galvanometer is connected in parallel between the first resistor (R1, R2) and the second resistor (R3, R4). This teaching aid can stimulate students' interest in learning resistance measurement knowledge, and promote students to continuously seek for resistance measurement. Knowledge innovation effectively guarantees the learning effect of students and increases students' confidence in undertaking challenging learning.

Description

A Teaching Aid Using Resistance Sorting and Measuring Circuit

technical field

The utility model relates to a teaching aid for measuring resistance, in particular to a teaching aid using resistance sorting and measuring circuits.

Background technique

In teaching experiments, multimeters and DC bridges are common teaching tools for students to measure resistance. In particular, the DC single-arm bridge is widely used in teaching because of its simple principle, strong inspiration, and can help students clearly understand the knowledge of resistance measurement. However, the teaching aid is insufficient in stimulating students' enthusiasm for innovation and challenging.

Utility model content

Aiming at the problems existing in the prior art, the utility model provides a teaching aid and a teaching method using a resistance sorting and measuring circuit. The teaching aid and the teaching method can stimulate students' interest in learning resistance measurement knowledge, and promote students to continuously seek the knowledge of resistance. Measuring knowledge innovation effectively guarantees students' learning effects and increases students' confidence in undertaking challenging learning.

In order to solve the technical problems existing in the prior art, the utility model adopts the following technical scheme: a kind of teaching aid adopting the resistance sorting and measuring circuit, including a power supply and a single-arm bridge circuit; To provide voltage, the input end of the single-arm bridge circuit is also connected in series with a switch and a sliding rheostat. One arm of the single-arm bridge circuit is composed of a resistance box to form a first resistor (R1, R2), and the other arm is composed of a resistor The bracket and the module resistors are combined to form a second resistor (R3, R4), and a galvanometer is parallelly connected between the first resistor (R1, R2) and the second resistor (R3, R4).

The second resistors are the module resistors connected in parallel or in series to the resistor support in groups.

The resistance bracket is a 9-well plate.

Intended effects of the utility model: First, the teaching aids and teaching methods provided by the utility model can effectively help students learn about resistance sorting and measurement. Through the demonstration of teaching aids combined with the teaching method, students can quickly understand what they have learned, and achieve twice the result with half the effort. Second, the teaching aids and teaching methods provided by the utility model transmit complex logical judgments to students through ingenious operating procedures, which greatly stimulates students' innovation ability, exercises students' hands-on ability, and enhances their confidence in accepting challenging learning.

Description of drawings

Fig. 1 is a kind of teaching aid of the utility model that adopts the resistance sorting measurement circuit.

Fig. 2 is a kind of operation flowchart of the teaching aid experiment resistor R3=R4 utilizing the resistance sorting measurement circuit of the present invention.

Fig. 3 is a flow chart of the operation of the teaching aid experiment resistance R3>R4 using the resistance sorting and measuring circuit of the present invention.

Fig. 4 is a flow chart of the operation of the teaching aid experiment resistance R3<R4 using the resistance sorting and measuring circuit of the present invention.

reference sign

Detailed ways:

Below in conjunction with accompanying drawing, the utility model is described in further detail:

As shown in Figure 1, the utility model provides a kind of teaching aid that adopts resistance sorting measurement circuit, comprises power supply 21, single-arm bridge circuit; Described power supply 21 provides voltage to described single-arm bridge circuit, and described single-arm bridge circuit The input end of the bridge circuit is also connected in series with a switch 22 and a sliding rheostat 23. One arm of the single-arm bridge circuit is composed of a resistance box 24 to form a first resistance (R1, R2), and the other arm is composed of a resistance bracket 25 and a module. The resistors 26 are combined to form a second resistor (R3, R4), and a galvanometer 27 is parallelly connected between the first resistor (R1, R2) and the second resistor (R3, R4). The second resistors (R1, R2) are the module resistors connected in series or in parallel to the resistor support in groups. The resistance bracket is a 9-well plate.

The utility model can also adopt a kind of teaching method that adopts the resistance sorting measurement teaching aid to solve technical problems: its steps are as follows:

First, first turn on the power supply of the resistance sorting measurement teaching aid, and adjust the sliding rheostat and the galvanometer at the same time to ensure the accuracy of the measurement process of the resistance sorting measurement teaching aid;

Second, adjust the first resistance (R1, R2) in the resistance sorting measurement teaching aid to make R1=R2, and compare the second resistance (R3, R4) simultaneously,

Third, group the second resistors (R3, R4) in step 2 according to 1 to 6; preferably, group the second resistors (R3, R4) in step 2 into groups of 4 Group, according to the balance of the bridge, compare the resistance values of the two groups of resistors in series or in parallel, and compare at least three times to sort out the special resistors and know their values relative to the other two groups. Fourth, the magnitude of the second resistors (R3, R4) can be obtained by observing the deflection direction of the galvanometer.

In the second step, the first resistor ((R1, R2) adopts a resistance box.

In the second step, the two resistor boxes in the first resistor ((R1, R2) are replaced by two resistors with the same resistance value.

In the second step, the two resistance boxes in the first resistance ((R1, R2) can be replaced by the measured resistance.

As shown in Figure 2, Figure 3, and Figure 4, 12 of the resistors are labeled, A1~A4, B1~B4, C1~C4, each operation is judged according to the relationship between R3 and R4, and subsequent judgments also use the previous The relationship between the size of R3 and R4 and the position of each resistor. When measuring, let R3=A1+A2+A3+A4, R4=B1+B2+B3+B4, close the switch S, and judge the three situations of R3=R4, R3>R4, R3<R4 according to the indication of the galvanometer .

Now, we utilize the teaching aid of the present utility model, adopt the method of the present utility model to carry out the experimental teaching of electric bridge principle sorting resistance to the student. Organize students to select one of the 12 resistors as a defective resistor. The resistance value is too large or too small. It is required to use the least number of comparisons to find out the defective resistor and measure its resistance. The experimental method is to adjust to make R1=R2, and perform the comparison operation of R3 and R4.

The easiest way is to exhaustively make R3 and R4 just one resistor, so that the two resistors are compared each time. If the bridge is balanced, it means that the two resistors are genuine products. If the bridge is unbalanced, it means that there are defective products in the two resistors. The judged genuine resistors are compared separately, and at most 8 times, you can know which is the defective resistor and know whether the resistance value is too large or too small.

The challenging experimental method can make the bridge comparison 3 times to find out the defective resistance and know that it is too large or too small.

(1) The 12 resistors are divided into three groups A, B, and C, with 4 resistors in each group. For the first time, each of the four groups of AB is connected in series to R3 and R4 for comparison. If it is unbalanced, it means that the 4 pieces in group C are genuine products, and the defective products are in group AB. If it is balanced, it means that group AB is genuine and there are defective products in group C.

(2) After comparison, if it is balanced, the defective product is in group C, take out two from group C and connect them in series to R3, and then take out one from group C and one from group A and connect them in series to R4 for comparison. If it is balanced, what is left in group C is a defective product, and then compare it with the genuine product, and the problem can be solved after 3 times; if it is unbalanced, take out the two resistors at R3 and connect them to R3 and R4 for comparison. The resistor at R3 is a defective product, otherwise R4 is a defective product, and then judge the size of the defective product according to the size relationship.

(3) If the defective product is in Group A and Group B, remember the size relationship of the current Group AB, and then take out 1 of each of Group ABC and connect them in series to R3, and 2 of Group B and 1 of Group C and connect them in series to R4 for comparison And write down the size relationship. At this time, there are 5 suspicious resistors and 1 genuine resistor on the bridge, and 3 suspicious resistors below. If the bridge is balanced, the 5 resistors on the bridge are genuine, and the 3 below are suspicious; otherwise, there are defective products among the 5 resistors on the bridge.

(4) If the following 3 questions are in doubt, compare the 2 access bridges in group A among the 3 questions. If it is balanced, the remaining group B is a defective product. According to the size relationship recorded earlier, it can be judged whether the defective product is too large or too small; if it is unbalanced, it depends on whether the size relationship changes. If there is no change, it is the one at the R3 position The resistance is a defective product; if it changes, it means that the R4 position is a defective product, and the size of the defective product is judged according to the size relationship recorded at the beginning.

If there are doubts about the 5 resistors, first check whether the size relationship is consistent with the original result. If it is changed, then the resistors of Group B at R3 and Group A at R4 are doubtful. You can compare one of these two with the original product. Solve the problem. If the size relationship remains unchanged, the other 3 resistors are doubtful, including 2 in group B and 1 in group A. Remove group A and connect the 2 resistors in group B to R3 and R4 respectively. If they are balanced, remove group A. If it is unbalanced, it depends on whether the size relationship has changed. If it is changed, the R3 is a defective product, and if it does not change, the R4 is a defective product. The size can be judged according to the previous comparison results.

In addition, the varistor can also be used for the comparison. Just change the first comparison:

The 12 resistors are divided into three groups A, B, and C, with 4 resistors in each group. Divide group A into two groups and connect them in series to R1 and R4 respectively, then divide group B into two groups and connect them in series to R2 and R3 respectively, compare and record the results. If it is balanced, it means that the AB group is normal, just take out two and connect them to R1 and R2 to replace the rheostat; The size of is the same as the result of directly comparing the size of group A and group B in series. Therefore, the same effect as the original can still be achieved after the modification, and will not affect the next two comparisons.

Those of ordinary skill in the art should understand that in practical applications, some changes may occur in the arrangement of the components in the present invention, and others may also make similar designs under the inspiration thereof. It should be pointed out that, as long as they do not deviate from the design purpose of the present utility model, all obvious changes and similar designs are included in the protection scope of the present utility model.

Claims (3)

1. a teaching aid that adopts resistance sorting measurement circuit, comprises power supply, single-arm bridge circuit; It is characterized in that, described power supply provides voltage to described single-arm bridge circuit, and described single-arm bridge circuit input terminal also A switch and a sliding rheostat are connected in series. One arm of the single-arm bridge circuit is composed of a resistance box to form a first resistor (R1, R2), and the other arm is composed of a resistor bracket and a module resistor to form a second resistor (R3, R4). ), a galvanometer is connected in parallel between the first resistor (R1, R2) and the second resistor (R3, R4). 2 . A teaching aid using a resistance sorting and measuring circuit according to claim 1 , wherein the second resistor is the module resistor connected in parallel or in series to the resistor support in groups. 3 . 3. A kind of teaching aid that adopts resistance sorting measurement circuit according to claim 1, is characterized in that, described resistance support is 9 hole plates.