Digital integrated Joule law quantitative experiment instrument

Abstract

The embodiment of the utility model discloses a digitalized integrated Joule law quantitative experiment instrument, comprising a pedestal which is provided with an adjustable power supply, a loop total current ammeter, a timing switch, a timing controller and a Joule law quantitative experiment unit. The Joule law quantitative experiment unit comprises a digital thermometer, a knife-shaped switch, a heating resistor, a vacuum interlayer cup, a slide wire resistor, a digital ammeter and two conductive rods, two ends of the heating resistor are respectively connected with the two conductive rods, the knife-shaped switch is connected in series with the heating resistor through the two conductive rods, two upper wiring ends of the knife-shaped switch are connected with two ends of the slide wire resistor, and two lower wiring ends of the knife-shaped switch are connected with the digital ammeter. The output end of the adjustable power supply and the knife-shaped switch form a loop for heating the heating resistor, the timing switch and the loop total current ammeter are connected in series in the loop, and the timing controller is used for timing and controlling the on and off of the timing switch. The quantitative experiment can be completed, the complicated experiment operation is simpler, the effect is intuitive, and the experiment success rate is high.

Description

Technical Field

[0001] The utility model relates to the field of teaching equipment, in particular to a digital integrated joule's law quantitative experiment instrument. Background Art

[0002] Joule's law is a very important experiment in junior high school electricity. The requirement of the curriculum standard is to "understand Joule's law through experiments". The teaching materials of the People's Education Edition design experimental equipment through the circuit shown in Figure 1. The electric heating wire heats the air, and the height difference generated by the rise of the liquid level in the U-shaped tube due to the difference in the degree of air expansion is used to judge which resistor generates more heat. During the experiment, the heat generation differences are studied from the following two points: ① Keep the current and the energization time the same, and the connected resistors are different; ② Keep the connected resistor and the energization time the same, and connect a same resistor in parallel with one of the resistors to make the current passing through the connected resistor different. In the experiment, the heat generated by the resistor is not directly measured, but the amount of electric heat is characterized by the size of the liquid level height difference generated on both sides of the U-shaped tube connected to the sealed container. The larger the height difference, the greater the heat generated by the resistor.

[0003] In addition, there is another kind of experimental equipment for "exploring Joule's law" as Figure 2 shown, which uses a common battery pack or a student power supply to supply power, and allows a fixed resistor to heat the kerosene in two containers. The temperature rise of the kerosene is measured by a traditional thermometer or an electronic thermometer to reflect the amount of heat released by the fixed resistor.

[0004] At present, these two common experimental equipment for "exploring Joule's law" in physics teaching can only perform qualitative experiments and cannot perform quantitative experiments, that is, the accurate quantitative relationship between electric heat Q, current and resistance cannot be obtained.

[0005] The disadvantages of the existing Joule's law experiment instrument are as follows:

[0006] (1) Qualitative measurement cannot be achieved. By heating the gas to make it expand (the temperature rises and the air pressure increases), the amount of heat released by the fixed resistor is reflected by the amount of the liquid column rise in the U-shaped tube connected to it, or the heat release is roughly measured by heating the liquid to increase the temperature, and only qualitative experiments can be performed.

[0007] (2) The operation is difficult and the experimental success rate is low. For the equipment that heats the gas to expand, the air tightness of the equipment should be fully considered. Any air leakage in the rubber tube, U-shaped tube, closed box and other equipment components will greatly reduce the experimental effect, and it is rather troublesome to check the air tightness before the experiment.

[0008] (3) It takes too long to collect data. The common Joule's law demonstrator for heating kerosene can only conduct single-group experiments. If quantitative measurements are to be made, at least 4 experiments need to be completed separately for the relationships between electric heat and resistance and between electric heat and current. These 8 experiments in total require at least half an hour. Therefore, it is basically impossible to conduct on-site demonstrations in class.

[0009] (4) The heat generated by the resistor is easily transferred to the surrounding environment, resulting in large errors. Ordinary glass beakers or conical flasks have very weak heat insulation ability from the outside air. The heat generated by the fixed-value resistor is quickly transferred to the surrounding air, especially in a cold environment, where the resulting errors are very large.

[0010] (5) When controlling the resistance R to be constant and studying the relationship between electric heat Q and current, the current can only be shunted by connecting a fixed-value resistor in parallel. The operation is complex and affected by the generally single resistance values of the fixed-value resistors in the laboratory. The current shunting ratio is monotonous, making it difficult to conduct universal experiments.

[0011] (6) The errors in temperature recording and measurement are large. Traditional alcohol and mercury thermometers have low accuracy. At the same time, manual reading requires looking straight at the scale corresponding to the bottom of the thermometer liquid surface. Therefore, during the rapid temperature rise process, the reading errors are often large.

[0012] (7) The measurement of time is complex. Each measurement requires manual pressing of the start, stop, and reset keys on the keyboard. When making multiple groups of data measurements during the temperature rise process, frequent manual timing not only increases the difficulty of the experimental operation but also brings more human errors. Utility Model Content

[0013] The technical problem to be solved by the embodiments of the present utility model is to provide a digital integrated Joule's law quantitative experiment instrument to realize the quantitative experiment of Joule's law and make the experimental operation simpler and the effect more intuitive.

[0014] To solve the above technical problems, an embodiment of the present utility model provides a digital integrated Joule's law quantitative experiment instrument, which includes a base. An adjustable power supply, a total circuit current ammeter, a timing switch, a timing controller, and a Joule's law quantitative experiment unit are provided on the base. The Joule's law quantitative experiment unit includes a digital thermometer, a knife switch, a heating resistor, a vacuum-insulated cup, a slide wire resistor, a digital ammeter, and two conducting rods. The two ends of the heating resistor are respectively connected to the two conducting rods. The heating resistor is used to heat the liquid in the vacuum-insulated cup. The knife switch is a double-headed switch. The knife switch is connected in series with the heating resistor through the two conducting rods. The two upper connection terminals of the knife switch are connected to the two ends of the slide wire resistor. The digital ammeter detects the current passing through the heating resistor. The digital thermometer includes a thermometer and a temperature sensor head for detecting the temperature of the liquid in the vacuum-insulated cup. The output terminal of the adjustable power supply and the knife switch form a circuit for heating the heating resistor. The timing switch and the total circuit current ammeter are connected in series in the circuit. The timing controller is used for timing and controlling the opening and closing of the timing switch.

[0015] Further, there are multiple groups of the Joule's law quantitative experiment units, and the multiple groups of Joule's law quantitative experiment units are connected in series with each other.

[0016] Further, a power on button for starting heating, a power off button for stopping heating, and a timing switch button for timing heating are provided on the base.

[0017] Further, an upper cover for sealing the vacuum-insulated cup is provided on the base.

[0018] Further, a card slot is provided on the base, and a card pin corresponding to the card slot is provided on the vacuum-insulated cup; the card pin and the card slot cooperate to fix the vacuum-insulated cup, so that the cup mouth of the vacuum-insulated cup is aligned with the upper cover for sealing and heat insulation.

[0019] Further, an air pipe joint for evacuating is provided on the vacuum-insulated cup.

[0020] Further, the heating resistor adopts a resistance wire.

[0021] Further, scales are correspondingly provided on the vacuum-insulated cup.

[0022] Further, a bracket is provided at the bottom of the base.

[0023] The beneficial effects of the present utility model are as follows: (1) The current experimental equipment for Joule's law can only conduct qualitative experiments, while the present utility model can complete quantitative experiments; (2) The integrated multi-group data measurement of the present utility model shortens the time required to complete quantitative experiments compared with the current technology; (3) The vacuum interlayer cup of the present utility model greatly reduces the heat exchange between the heated liquid and the outside world compared with the current technology; (4) The resistors used for current shunting in the present utility model are adjustable, increasing the universality of experimental data and making the conclusions drawn more credible compared with existing equipment; (5) The digital temperature sensors, ammeters, timing controllers, etc. of the present utility model make complex experimental operations simpler, with intuitive effects and a high experimental success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the first experimental circuit in the prior art.

[0025] Figure 2 is a schematic diagram of the second experimental circuit in the prior art.

[0026] Figure 3 is a three-dimensional structure diagram of the digital integrated Joule's law quantitative experiment instrument according to an embodiment of the present utility model.

[0027] Figure 4 is a rear view of the digital integrated Joule's law quantitative experiment instrument according to an embodiment of the present utility model.

[0028] Figure 5 is a side view of the digital integrated Joule's law quantitative experiment instrument according to an embodiment of the present utility model.

[0029] Figure 6 is Figure 5 a sectional view taken along line A-A in

[0030] Figure 7 is a schematic diagram of the circuit structure of the digital integrated Joule's law quantitative experiment instrument according to an embodiment of the present utility model.

[0031] REFERENCE NUMERAL DESCRIPTION OF THE DRAWINGS

[0032] Base 1, adjustable power supply 2, total loop current ammeter 3, timing switch 4, timing controller 5, thermometer 6, temperature sensor 7, knife switch 8, heating resistor 9, vacuum interlayer cup 10, slide wire resistor 11, digital ammeter 12, power on button 13, power off button 14, timing switch button 15, upper cover 16, card slot 17, retaining pin 18, bracket 19, air pipe joint 20, conducting rod 21. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following further describes the present utility model in detail with reference to the drawings and specific embodiments.

[0034] In the embodiments of the present utility model, if there are directional indications (such as up, down, left, right, front, back...), they are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture (as shown in the drawings). If this specific posture changes, the directional indications will also change accordingly.

[0035] In addition, in the present utility model, the descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0036] Please refer to Figures 3 to 7 , the digital integrated Joule's law quantitative experiment instrument of the embodiment of the present utility model includes a base.

[0037] An adjustable power supply, a loop total current ammeter, a timing switch, a timing controller, and a Joule's law quantitative experiment unit are provided on the base. The Joule's law quantitative experiment unit includes a digital thermometer, a knife switch, a heating resistor, a vacuum interlayer cup, a slide wire resistor, a digital ammeter, and two conductive rods. The adjustable power supply can adopt an existing adjustable DC regulated teaching power supply.

[0038] The present utility model insulates the heated liquid through the vacuum interlayer cup, greatly reducing the heat exchange between the heated liquid and the external environment. Preferably, an air pipe joint for vacuum pumping is provided on the vacuum interlayer cup. The vacuum interlayer cup is formed by two layers of glass to form a middle interlayer. The gas in the interlayer is extracted by a vacuum pump to form a vacuum environment, so that the heat loss of the heated liquid is very low within the experimental time, greatly improving the accuracy of the experiment.

[0039] Both ends of the heating resistor are respectively connected to two conductive rods. The heating resistor is used to heat the liquid to be heated in the vacuum interlayer cup. Preferably, the two conductive rods are suspended below the base. The digital thermometer includes a temperature gauge and a temperature sensing head for detecting the temperature of the liquid in the vacuum interlayer cup. Preferably, the temperature sensing head is suspended below the base. The temperature gauge real-time displays the temperature measured by the temperature sensing head. The present utility model measures the temperature of the liquid to be heated through the digital thermometer, with quick and convenient reading, and can quickly record the changing temperature.

[0040] The knife switch is a double-headed switch. The knife switch is connected in series with the heating resistor through two conductive rods. The two upper terminals of the knife switch are connected to both ends of the slide wire resistor. That is, the double-headed switch has six pins. The two upper pins are respectively connected to both ends of the slide wire resistor, and the two middle pins are respectively connected to the two conductive rods. Closing the knife switch by turning it upward can connect the slide wire resistor. The utility model shunts the current of the heating resistor through the slide wire resistor. The operation is simple. Compared with shunting with a fixed-value resistor, the slide wire resistor only needs to rotate the knob to achieve various sizes of shunting, which is more accurate, has a wider adjustment range, and can easily complete multiple experiments.

[0041] The digital ammeter is connected in series between the knife switch and the conductive rod to detect the current passing through the heating resistor. The utility model quickly measures the real-time current of the heating resistor through the digital ammeter, which is convenient for measuring and adjusting the current magnitude.

[0042] The knife switches of multiple Joule's law quantitative experiment units are connected in series, that is, the two middle pins of multiple knife switches are connected in series in sequence. The previous middle pin of the first knife switch and the latter middle pin of the last knife switch are respectively connected to one pole of the input end of the adjustable power supply and the other pole of the input end of the adjustable power supply through the series-connected timing switch and connected to the loop total current ammeter.

[0043] The output end of the adjustable power supply and the knife switch form a loop for heating the heating resistor. The timing switch and the loop total current ammeter are connected in series in the loop. The timing controller is used for timing and controlling the opening and closing of the timing switch. The utility model can achieve accurate measurement for a long time through the timing switch and the timing controller. The timing switch can set the heating time. Since it takes a certain time for the heat of the heating resistor to be transferred to the liquid to be heated to achieve stable temperature rise, the utility model can accurately set the total measurement time according to the needs of the user's experiment through the timing switch, and can record relevant experimental data according to each time node by observing the time display on the timing controller, making the entire long-time measurement easier and more accurate.

[0044] As an implementation manner, there are multiple groups of Joule's law quantitative experiment units, and multiple groups of Joule's law quantitative experiment units are connected in series with each other. The heating resistors of multiple groups of Joule's law quantitative experiment units can adopt different resistance values.

[0045] As an implementation manner, a power on button for starting heating, a power off button for stopping heating, and a timing switch button for timing heating are provided on the base. The utility model is convenient for users to operate through the button design.

[0046] As an implementation manner, a top cover for sealing the vacuum-insulated cup is provided on the base. The top cover of the present utility model seals the cup mouth of the vacuum-insulated cup, further reducing the heat loss of the heated liquid during the experiment time and greatly improving the accuracy of the experiment.

[0047] As an implementation manner, a clamping groove is provided on the base, and a clamping pin corresponding to the clamping groove is provided on the vacuum-insulated cup; the clamping pin and the clamping groove cooperate to fix the vacuum-insulated cup, aligning the cup mouth of the vacuum-insulated cup with the top cover for sealing and heat insulation, facilitating the user to disassemble and assemble the vacuum-insulated cup.

[0048] As an implementation manner, the heating resistor uses a resistance wire.

[0049] As an implementation manner, scales are correspondingly provided on the vacuum-insulated cup, facilitating the user to observe the volume of the heated liquid.

[0050] As an implementation manner, a bracket is provided at the bottom of the base.

[0051] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalent scope.

Claims

1. A digital integrated Joule's law quantitative experimental instrument, characterized in that: The invention comprises a base, on which an adjustable power supply, a circuit total current ammeter, a timing switch, a timing controller and a Joule's law quantitative experiment unit are arranged. The Joule's law quantitative experiment unit comprises a digital thermometer, a knife switch, a heating resistor, a vacuum sandwich cup, a sliding wire resistor, a digital ammeter and two conductive rods. Two conductive rods are respectively connected to both ends of the heating resistor. The heating resistor is used to heat the liquid in the vacuum sandwich cup. The knife switch is a double-headed switch. The knife switch is connected in series with the heating resistor through the two conductive rods. Two upper terminals of the knife switch are connected to both ends of the sliding wire resistor. The digital ammeter detects the current passing through the heating resistor. The digital thermometer comprises a thermometer and a temperature sensing head for detecting the temperature of the liquid in the vacuum sandwich cup. The output end of the adjustable power supply and the knife switch form a circuit for heating the heating resistor. The timing switch and the circuit total current ammeter are connected in series in the circuit. The timing controller is used for timing and controlling the opening and closing of the timing switch.

2. The digital integrated Joule's law quantitative experiment instrument as claimed in claim 1, characterized in that: The Joule's law quantitative experimental units have multiple groups, and the multiple groups of Joule's law quantitative experimental units are connected in series.

3. The digital integrated Joule's law quantitative experiment instrument as claimed in claim 1, characterized in that: The base is provided with a power on button for starting heating, a power off button for stopping heating, and a timer switch button for timed heating.

4. The digital integrated Joule's law quantitative experiment instrument as claimed in claim 1, characterized in that: An upper cover for sealing the vacuum sandwich cup is arranged on the base.

5. The digital integrated Joule's law quantitative experiment instrument as claimed in claim 4, characterized in that: The base is provided with a slot, and the vacuum sandwich cup is provided with a latch corresponding to the slot; the latch and the slot cooperate to fix the vacuum sandwich cup so that the cup mouth of the vacuum sandwich cup is aligned with the upper cover for sealing and heat insulation.

6. The digital integrated Joule's law quantitative experiment instrument as claimed in claim 1, characterized in that: The vacuum sandwich cup is provided with an air pipe joint for vacuuming.

7. The digital integrated Joule's law quantitative experiment instrument according to claim 1, characterized in that: The heating resistor adopts resistance wire.

8. The digital integrated Joule's law quantitative experiment instrument according to claim 1, characterized in that: The vacuum sandwich cup is provided with corresponding scales.

9. The digital integrated Joule's law quantitative experiment instrument according to claim 1, characterized in that: A bracket is provided at the bottom of the base.

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