Thermistor experimental instrument for teaching demonstration

Abstract

The utility model relates to the technical field of teaching instruments, and discloses a thermistor experiment instrument for teaching demonstration, which comprises a shell, a transparent observation plate is embedded and fixed on the surface of the front side of the shell, a control module is embedded and fixed on the surface of the transparent observation plate, and a transparent cover plate is hinged above the back of the shell. A DC power interface and a USB data interface are installed on the right side of the shell, an objective table is fixed to the bottom of the inner wall of the shell, a probe placing hole is formed in the center of the objective table, a PTC heating piece is embedded and fixed to the surface of the objective table, a semiconductor chilling plate is fixed to the bottom of the objective table, a thermistor probe is arranged above the objective table, and the thermistor probe is arranged on the surface of the objective table. And four double-bit nixie tubes are fixed at the left upper part of the surface of the transparent observation plate. According to the thermistor experimental instrument for teaching demonstration, through highly integrated design, traditional dispersed heating, refrigerating and measuring modules are integrated into single equipment, and the experimental operation process is greatly simplified.

Description

Technical Field

[0001] This utility model relates to the field of teaching instrument technology, specifically a thermistor experimental instrument for teaching demonstrations. Background Technology

[0002] Thermistor experiments are practical teaching activities that study the temperature characteristics (such as negative temperature coefficient NTC or positive temperature coefficient PTC) of thermistors by measuring the change of their resistance value with temperature. They transform the abstract formula of "resistance changes with temperature" (such as the exponential relationship of NTC) into visual experimental data, and verify parameters such as the thermistor's B value (material constant) through experimental data, thereby enhancing the understanding of semiconductor characteristics.

[0003] The utility model patent with authorization announcement number CN201662914U discloses a thermistor experimental device, including a box. The key structural features are that the upper surface of the box is provided with a thermistor socket, a light bulb, an ammeter, a battery box, and a switch. The inside of the box is provided with a control circuit. The thermistor socket, light bulb, ammeter, battery box, and switch are connected by wires. The control circuit adopts a comparator circuit.

[0004] However, the existing technical solutions described above still have the following shortcomings: Existing teaching thermistor demonstration devices use a simple light bulb and ammeter pointer to display the thermistor characteristics, which suffers from inaccurate temperature control, unintuitive display, and lack of safety protection. Students find it difficult to simultaneously observe the relationship between temperature and resistance changes, and the experimental modes are limited. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a thermistor experimental instrument for teaching demonstration, so as to solve the problems mentioned in the background technology.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a thermistor experimental instrument for teaching demonstration, comprising a housing, a transparent observation plate embedded and fixed on the front surface of the housing, a control module embedded and fixed on the surface of the transparent observation plate, a transparent cover plate hinged to the upper back of the housing, a DC power interface and a USB data interface installed on the right side of the housing, a stage fixed to the bottom of the inner wall of the housing, a probe insertion hole opened in the center of the stage, a PTC heating element embedded and fixed on the surface of the stage, a semiconductor cooling element fixed at the bottom of the stage, a thermistor probe arranged above the stage, four two-digit digital tubes fixed to the upper left of the surface of the transparent observation plate, a mode switching knob, a temperature adjustment knob, a contrast potential adjustment knob and a hold button installed on the front side of the housing, and a temperature sensor fixed on the surface of the stage.

[0007] Preferably, the control module includes a microcontroller, a constant current source module, and an over-temperature protection circuit. The microcontroller is connected to each module slot, the output of the constant current source module is connected to the thermistor probe interface via a gold-plated spring pin, and the over-temperature protection circuit is a bimetallic strip temperature control switch connected in series in the heating circuit.

[0008] Preferably, a support rod is fixed to the bottom of the inner wall of the housing, and a spring clip is slidably connected to the surface of the support rod, with the thermistor probe located inside the spring clip.

[0009] Preferably, heat dissipation fins are fixed to the bottom of the semiconductor cooling chip.

[0010] Preferably, the top of the PTC heating element is covered with a 0.5mm mica insulating layer.

[0011] Preferably, both the transparent cover and the transparent observation plate are made of high-temperature resistant acrylic material.

[0012] Preferably, a heat dissipation mesh is fixed to the left side of the housing, and a fan is fixed to the right side of the inner wall of the housing.

[0013] Compared with the prior art, the beneficial effects achieved by this utility model are:

[0014] This device, through its highly integrated design, consolidates traditionally fragmented heating, cooling, and measurement modules into a single unit, significantly simplifying experimental procedures. A dual-digit digital display simultaneously shows temperature and resistance values, enabling students to intuitively understand the negative temperature coefficient characteristic of thermistors and avoiding the cumbersome switching between multimeters and temperature control instruments required in traditional experiments. The transparent observation panel and closable transparent cover significantly enhance the visualization of experimental phenomena, allowing students to directly observe the physical effects of stage temperature changes on the thermistor, transforming abstract theoretical knowledge into concrete sensory understanding. Diverse adjustment knobs support various experimental modes, including heating, cooling, and manual current adjustment. Teachers can flexibly design experimental content according to the teaching progress, covering everything from basic characteristic verification to application circuit expansion, fully stimulating students' interest in inquiry and innovative thinking. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0016] Figure 2 This is a three-dimensional structural schematic diagram of the present invention from another perspective;

[0017] Figure 3 This is a cross-sectional structural diagram of the present invention;

[0018] Figure 4 This is a partial structural schematic diagram of the present invention.

[0019] The components include: 1. Housing; 2. Transparent observation plate; 3. Control module; 4. Transparent cover; 5. DC power interface; 6. USB data interface; 7. Stage; 8. Probe insertion hole; 9. PTC heating element; 10. Semiconductor cooling element; 11. Thermistor probe; 12. Two-digit digital tube; 13. Mode switching knob; 14. Temperature adjustment knob; 15. Contrast potential adjustment knob; 16. Hold button; 17. Heat dissipation mesh; 18. Fan; 19. Heat dissipation fins; 20. Temperature sensor; 21. Support rod; 22. Spring clip. Detailed Implementation

[0020] The specific embodiments of this utility model will now be described in further detail with reference to the accompanying drawings.

[0021] Please see Figure 1-4 A thermistor experimental instrument for teaching demonstration includes a housing 1, a transparent observation plate 2 embedded and fixed on the front surface of the housing 1, a control module 3 embedded and fixed on the surface of the transparent observation plate 2, a transparent cover plate 4 hinged to the upper back of the housing 1, a DC power interface 5 and a USB data interface 6 installed on the right side of the housing 1, a stage 7 fixed to the bottom of the inner wall of the housing 1, a probe insertion hole 8 opened in the center of the stage 7, a PTC heating element 9 embedded and fixed on the surface of the stage 7, a semiconductor cooling element 10 fixed at the bottom of the stage 7, a thermistor probe 11 set above the stage 7, four two-digit digital tubes 12 fixed to the upper left of the surface of the transparent observation plate 2, a mode switching knob 13, a temperature adjustment knob 14, a contrast potential adjustment knob 15 and a hold button 16 installed on the front side of the housing 1, and a temperature sensor 20 fixed to the surface of the stage 7.

[0022] Through the above technical solution, the housing 1 serves as the main support structure, and its front transparent observation plate 2 allows direct observation of the state changes of the thermistor probe 11 on the stage 7 during the experiment; the control module 3 is integrated on the surface of the transparent observation plate 2, and uses a microcontroller to collect data from the temperature sensor 20 and the thermistor probe 11 in real time, and drives the dual-digit digital tube 12 to display the temperature and resistance values ​​synchronously; the transparent cover 4 is opened and closed through a hinge structure, which facilitates the placement and adjustment of the probe; the DC power interface 5 provides a safe voltage for the PTC heating element 9 and the semiconductor cooling element 10, and the USB data interface 6 supports the export of experimental data; the thermistor probe 11 is placed in the stage 7 through the central probe insertion hole 8, and the PTC heating element embedded in its surface... The stage 9 works in conjunction with the bottom semiconductor cooling chip 10 to achieve bidirectional temperature control; the mode switching knob 13 controls the switching between heating, cooling, and room temperature modes; the temperature adjustment knob 14 sets the target temperature; the comparison potential adjustment knob 15 adjusts the test current to observe the resistance characteristics under different working conditions; the hold button 16 is used to lock the current data; the transparent observation plate 2 and transparent cover plate 4 of the housing 1 make the experimental process visible and enhance the intuitiveness of teaching; the dual-digit digital tube 12 displays the temperature and resistance values ​​simultaneously, which is convenient for students to compare and analyze in real time; multiple adjustment knobs support diverse experimental modes to meet different teaching needs; the stage 7 integrates heating and cooling functions, which can achieve a wide range of temperature changes within a single device, reducing the switching time of experimental equipment.

[0023] Control module 3 includes a microcontroller, a constant current source module, and an over-temperature protection circuit. The microcontroller is connected to each module slot. The output of the constant current source module is connected to the interface of the thermistor probe 11 via a gold-plated spring pin. The over-temperature protection circuit is a bimetallic temperature control switch connected in series in the heating circuit.

[0024] Through the above technical solution, the microcontroller receives the analog signals from the temperature sensor 20 and the thermistor probe 11, calculates the temperature and resistance values ​​after AD conversion, and provides a stable current to the thermistor probe 11 through the constant current source module to ensure measurement accuracy; the over-temperature protection circuit adopts a bimetallic strip temperature control switch, which automatically disconnects the power supply circuit of the PTC heating element 9 when the temperature of the stage 7 exceeds the threshold.

[0025] A support rod 21 is fixed to the bottom of the inner wall of the housing 1. A spring clip 22 is slidably connected to the surface of the support rod 21. The thermistor probe 11 is located inside the spring clip 22.

[0026] Through the above technical solution, the support rod 21 is used to position the spring clip 22. The spring clip 22 can fix the position of the thermistor probe 11 during use, reducing the risk of the probe accidentally falling off during the experiment.

[0027] The bottom of the semiconductor cooling chip 10 is fixed with heat dissipation fins 19.

[0028] Through the above technical solution, the heat generated when the semiconductor cooling chip 10 is working is increased by the bottom heat dissipation fins 19 and the contact area with the air. Combined with natural convection or forced heat dissipation by the fan 18, the heat is dissipated faster to maintain the cooling efficiency.

[0029] The top of the PTC heating element 9 is covered with a 0.5mm mica insulation layer.

[0030] Through the above technical solutions, the mica insulation layer effectively prevents the risk of leakage and ensures the safety of experimental operations.

[0031] Both the transparent cover plate 4 and the transparent observation plate 2 are made of high-temperature resistant acrylic material.

[0032] Through the above technical solution, the transparent cover plate 4 and the transparent observation plate 2 are made of high temperature resistant acrylic material, which maintains transparency and structural strength in high temperature environment, allows observation of the experimental process and withstands the temperature change impact of the stage 7.

[0033] A heat dissipation mesh 17 is fixed on the left side of the housing 1, and a fan 18 is fixed on the right side of the inner wall of the housing 1.

[0034] Through the above technical solution, the heat dissipation mesh 17 on the left side of the housing 1 accelerates air circulation through dense holes, and works with the fan 18 on the right side to actively exhaust air, forming a forced convection heat dissipation system to quickly dissipate the heat accumulated inside the housing 1.

[0035] Working Principle: This device uses an integrated temperature control and data acquisition system to visualize the characteristics of thermistors for teaching demonstration. When the experiment starts, the user selects heating, cooling, or natural temperature change mode using the mode switching knob 13, and sets the target temperature value using the temperature adjustment knob 14. Based on real-time data from the temperature sensor 20, the microcontroller dynamically adjusts the power output of the PTC heating element 9 or the cooling intensity of the semiconductor cooling element 10 using a PID algorithm, enabling the stage 7 to quickly reach the set temperature and maintain stability. The constant current source module provides a constant current to the thermistor probe 11, and the voltage across its terminals is processed by a differential amplifier circuit and input to the microcontroller. Combined with the temperature data, the microcontroller calculates the resistance value and drives the two-digit digital tube 12. The synchronous display and the contrast potential adjustment knob 15 allow manual adjustment of the test current, enabling observation of the resistance-temperature characteristics under different bias conditions. During the experiment, the over-temperature protection circuit monitors the temperature of the stage 7 in real time. If the temperature exceeds the safety threshold, the heating circuit is immediately cut off. The heat dissipation system, consisting of the heat dissipation mesh 17 and the fan 18, continuously dissipates internal heat to maintain stable operation of the equipment. The transparent observation plate 2 and the transparent cover plate 4 allow students to visually observe the physical state changes of the thermistor at different temperatures. The USB data interface 6 supports the export of experimental data for post-class analysis. Compared with traditional devices, this design significantly improves the efficiency and safety of teaching demonstrations through a three-in-one temperature control system, dual-parameter real-time display, and multiple safety protection mechanisms.

[0036] Although specific embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these specific embodiments without departing from the principles and spirit, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A thermistor experimental apparatus for teaching demonstrations, comprising a housing (1), characterized in that: A transparent observation plate (2) is embedded and fixed on the front surface of the housing (1). A control module (3) is embedded and fixed on the surface of the transparent observation plate (2). A transparent cover plate (4) is hinged to the upper back of the housing (1). A DC power interface (5) and a USB data interface (6) are installed on the right side of the housing (1). A stage (7) is fixed to the bottom of the inner wall of the housing (1). A probe insertion hole (8) is opened in the center of the stage (7). A PT is embedded and fixed on the surface of the stage (7). C heating element (9), a semiconductor cooling element (10) is fixed at the bottom of the stage (7), a thermistor probe (11) is set above the stage (7), four dual-digit digital tubes (12) are fixed on the upper left side of the transparent observation plate (2), a mode switching knob (13), a temperature adjustment knob (14), a contrast potential adjustment knob (15) and a hold button (16) are installed on the front side of the housing (1), and a temperature sensor (20) is fixed on the surface of the stage (7).

2. The thermistor experimental apparatus for teaching demonstration according to claim 1, characterized in that: The control module (3) includes a microcontroller, a constant current source module and an over-temperature protection circuit. The microcontroller is connected to each module slot. The output end of the constant current source module is connected to the interface of the thermistor probe (11) via a gold-plated spring pin. The over-temperature protection circuit is a bimetallic strip temperature control switch connected in series in the heating circuit.

3. The thermistor experimental apparatus for teaching demonstration according to claim 1, characterized in that: A support rod (21) is fixed to the bottom of the inner wall of the housing (1), and a spring clip (22) is slidably connected to the surface of the support rod (21). The thermistor probe (11) is located inside the spring clip (22).

4. The thermistor experimental apparatus for teaching demonstration according to claim 1, characterized in that: The bottom of the semiconductor cooling chip (10) is fixed with heat dissipation fins (19).

5. The thermistor experimental apparatus for teaching demonstration according to claim 1, characterized in that: The top of the PTC heating element (9) is covered with a 0.5mm mica insulation layer.

6. The thermistor experimental apparatus for teaching demonstration according to claim 1, characterized in that: Both the transparent cover plate (4) and the transparent observation plate (2) are made of high-temperature resistant acrylic material.

7. The thermistor experimental apparatus for teaching demonstration according to claim 1, characterized in that: A heat dissipation mesh (17) is fixed on the left side of the housing (1), and a fan (18) is fixed on the right side of the inner wall of the housing (1).

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