CN104064076A - Experimental facility using unbalanced bridge to design electrical resistance thermometer - Google Patents
Experimental facility using unbalanced bridge to design electrical resistance thermometer Download PDFInfo
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- CN104064076A CN104064076A CN201410258214.9A CN201410258214A CN104064076A CN 104064076 A CN104064076 A CN 104064076A CN 201410258214 A CN201410258214 A CN 201410258214A CN 104064076 A CN104064076 A CN 104064076A
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Abstract
The invention provides an experimental facility using an unbalanced bridge to design an electrical resistance thermometer. According to the experimental facility, the bridge is composed of adjustable bridge arm resistors R1, R2 and R2 and a thermistor Rt. An adjustable voltage source is used for supplying power to the bridge. The thermistor is arranged in a glass water tank. A semiconductor refrigeration device, a heating device and a temperature sensor are arranged in the water tank. Output voltage of the bridge is displayed on a digital voltmeter after being amplified through an operational amplifier. The adjustable bridge arm resistors are adjusted appropriately, the temperature t of heat transfer liquid is set through a temperature controller, the output voltage Uo(t) of the bridge is read, the temperature is measured at certain time intervals, a Uo(t)-t curve is drawn, and the temperature t can be measured through the Uo(t). According to the experimental facility, the adjustable bridge arm resistors serve as bridge arms of the unbalanced bridge, as a result, the sensitivity of the designed thermometer can be improved, the measurement range of the designed thermometer can be expanded to below room temperature, the magnitude of the output voltage of the bridge is convenient to adjust, and the numerical value displayed by the designed thermometer is just the centigrade temperature value of an object to be measured easily.
Description
Technical field
The present invention relates to a kind of physics facility, specifically relate to a kind of experimental provision that utilizes nonequilibrium bridge design resistance thermometer.
Background technology
The measurement of temperature be controlled at we daily life and production, scientific research in be widely used, for example, fire alarm annunciator, constant temperature oven, refrigerator etc.In these application apparatus, be usually that electric signal is gone to control topworks's work by " processing " later.But in " processing " before, first the temperature signal being provided by controlled system must be converted to corresponding electric signal, temperature sensor is exactly the device of carrying out this task.Semiconductor thermistor is that a kind of resistance is with the sensitive element of temperature change generation marked change, in operating temperature range, resistance with temperature raise increase be called positive temperature coefficient (PTC) (Positive TemperatureCoefficient is called for short PTC) thermistor, otherwise be called negative temperature coefficient (Negative TemperatureCoefficient is called for short NTC) thermistor.Thermistor have volume little, react the advantage such as fast, easy to use, by thermistor, the variation that temperature and variation thereof can be converted to electrical quantities or electrical quantities is measured.So it is widely used in the temperature survey and control work of the every field such as work, agriculture, doctor, traffic, military affairs, scientific research.
Direct current bridge is a kind of electricity measuring Instrument of precision, can be divided into balanced bridge and nonequilibrium bridge two classes.Balanced bridge is by regulating bridge balance, testing resistance and measuring resistance being compared to the size that obtains testing resistance, if Huygens's electric bridge, Kelvin bridge etc. are all balanced type direct current electric bridges.Due to needs adjustment, so balanced bridge can only be for measuring the physical quantity with metastable state.Along with the development of measuring technique, the application of electric bridge is no longer confined to the scope of balanced bridge, and nonequilibrium bridge is used widely in the measurement of non electrical quantity.In Practical Project and scientific experiment, continually varying often to be measured, as long as can connect the variation of same resistance value to be measured, just can adopt nonequilibrium bridge to measure.By various resistance type sensor access bridge circuits, the output voltage on bridge road just can reflect the subtle change of arm resistance, therefore, just can detect variation to be measured, as temperature, pressure, humidity etc. by measuring the output voltage of nonequilibrium bridge.
Utilizing the experiment of nonequilibrium bridge design resistance thermometer is a common experimental project in Physical Experiment, and it is a more typical nonequilibrium bridge application example, is the blank of all kinds of digital thermometers on market, has certain practical value.
Utilize at present the experimental provision of nonequilibrium bridge design resistance thermometer mainly to have the following disadvantages:
One, the general single-deck rheostat that adopts fixedly stepping amount, certain gear of brachium pontis of nonequilibrium bridge, resistance adjustable extent is smaller, in a lot of situations, can not adapt with thermistor, makes the thermometer remolding sensitivity of design lower, affects experiment effect.
Its two, heating source temperature controller is generally power supply heating, fan cooled, using air as heat transfer substance, be heated inhomogeneous, measurement range can only be generally room temperature or higher than room temperature, cannot study the situation lower than room temperature, the thermometer measure scope of design is restricted.
Its three, bridge output voltage size is difficult for regulating, being difficult to make the numerical value that the thermometer of design shows is just in time the celsius temperature scale of object under test.
Summary of the invention
In order to overcome the above-mentioned deficiency of prior art, the present invention proposes a kind of experimental provision that utilizes nonequilibrium bridge design resistance thermometer, this device adopts adjustable arm resistance as the brachium pontis of nonequilibrium bridge, resistance adjustable extent is large, can match with all kinds of thermistors, thus the sensitivity that improves design temperature meter.Using liquid as heat transfer substance, be heated evenly, and the thermometer measure scope of design can extend to below room temperature.Bridge output voltage size adjustment is convenient, and easily making the numerical value of the thermometer demonstration of design is just in time the celsius temperature scale of object under test.
The technical solution adopted for the present invention to solve the technical problems is: by adjustable arm resistance R
1, R
2, R
3and semiconductor thermistor or metal thermo-sensitive resistance R
tas four brachium pontis of electric bridge, form an electric bridge respectively, by variable voltage source, to electric bridge, provide power supply, the size of voltage source output voltage can regulate by knob, and can on voltage source voltage display screen, show.Semiconductor thermistor or metal thermo-sensitive resistance are placed in the glass flume of one end sealing, and bath of glass cell wall adopts double-decker, and centre is evacuated, to play good heat insulation effect.In heat transfer liquids implantation glass tank, highly suitable, in glass flume, in heat transfer liquids, top part arranges semiconductor refrigerating plant, be used for Cooling Heat Transfer liquid, part arranges a heating arrangement on the lower, be used for heating heat transfer liquids, center section arranges a temperature sensor, be used for measuring the temperature of heat transfer liquids, semiconductor cooling device, heating arrangement and temperature sensor are connected with temperature controller by interface respectively, can set the temperature of heat transfer liquids by the button on temperature controller.By the temperature of pressing key assignments heat transfer liquids on temperature controller, utilize the actual temperature of temperature sensor measurement heat transfer liquids, temperature controller inside is controlled by microprocessor, if design temperature is lower than actual temperature, start semiconductor cooling device, Cooling Heat Transfer liquid, until temperature is reduced to setting value; If design temperature, higher than actual temperature, starts heating arrangement, heating heat transfer liquids, until temperature is increased to setting value.The output terminal concatenation operation amplifier one of electric bridge, as a reverse voltage amplifier, voltage amplification factor can be by changing adjustable feedback resistance R
fand adjustable input resistance R
isize regulate, the output voltage of electric bridge is amplified, then through operational amplifier two outputs as output buffer, on the voltage display screen of digital voltmeter, shows.During experimental implementation, the resistance in temperature-measuring range according to semiconductor thermistor or metal thermo-sensitive resistance first, by adjustable arm resistance R
1, R
2and R
3size adjustment suitable, then by the temperature t of pressing key assignments heat transfer liquids on temperature controller, it is the temperature of semiconductor thermistor or metal thermo-sensitive resistance, it is suitable that the voltage amplification factor of operational amplifier one is regulated, and finally by the voltage display screen of digital voltmeter, reads the output voltage U of electric bridge
o(t), every uniform temperature, measure once, be recorded in table, and draw U
o(t)～t curve, so just can pass through U
o(t) measure temperature t.By suitably choosing arm resistance, adjustable feedback resistance R
fand adjustable input resistance R
ivalue, can make the magnitude of voltage that the voltage display screen of digital voltmeter shows is just in time the celsius temperature scale of object under test.
The invention has the beneficial effects as follows, the resistance thermometer measurement range of this experimental provision design can extend to below room temperature, adopt adjustable arm resistance as the brachium pontis of nonequilibrium bridge, can match with all kinds of thermistors, thereby can improve the sensitivity of design temperature meter, bridge output voltage size adjustment is convenient, and easily making the numerical value of the thermometer demonstration of design is just in time the celsius temperature scale of object under test.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the present invention is further described.
Accompanying drawing is structural representation of the present invention.
1. adjustable arm resistance R in figure
1, 2. adjustable arm resistance R
2, 3. adjustable arm resistance R
3, 4. semiconductor thermistor or metal thermo-sensitive resistance R
t, 5. variable voltage source, 6. voltage source voltage display screen, 7. adjustable voltage source output terminal interface, 8. variable voltage source power switch, 9. variable voltage source voltage swing adjusting knob, 10. heating arrangement, 11. temperature sensors, 12. semiconductor cooling devices, interface between 13. heating arrangements and temperature controller, interface between 14. temperature sensors and temperature controller, interface between 15. semiconductor cooling devices and temperature controller, 16. temperature displays, 17. temperature controllers, 18. digital selection keys, 19. raise button, 20. lower button, 21. pilot lamp, 22. reset keys, 23. Temperature Setting buttons, 24. adjustable feedback resistance R
f, 25. adjustable input resistance R
i, 26. operational amplifier one, 27. operational amplifier two, 28. digital voltmeter input end interface, 29. digital voltmeters, 30. digital voltmeter voltage display screens, 31. digital voltmeter power switches, 32. digital voltmeter range gear adjusting knobs, 33,34. common ground ends, 35. glass flumes.
Embodiment
In accompanying drawing, by adjustable arm resistance R
11, adjustable arm resistance R
22, adjustable arm resistance R
33 and semiconductor thermistor or metal thermo-sensitive resistance R
t4 respectively as four brachium pontis of electric bridge, form an electric bridge, by variable voltage source 5, by adjustable voltage source output terminal interface 7, to electric bridge, provide power supply, the size of voltage source output voltage can regulate by variable voltage source voltage swing adjusting knob 9, and can on voltage source voltage display screen 6, show.Semiconductor thermistor or metal thermo-sensitive resistance R
t4 are placed in the glass flume 35 of one end sealing, and bath of glass cell wall adopts double-decker, and centre is evacuated, to play good heat insulation effect.In heat transfer liquids implantation glass tank 35, highly suitable, in the interior heat transfer liquids of glass flume 35, top part arranges semiconductor refrigerating plant 12, be used for Cooling Heat Transfer liquid, part arranges a heating arrangement 10 on the lower, be used for heating heat transfer liquids, center section arranges a temperature sensor 11, be used for measuring the temperature of heat transfer liquids, semiconductor cooling device 12, heating arrangement 10 and temperature sensor 11 are respectively by the interface 15 between semiconductor cooling device and temperature controller, heating arrangement is connected with temperature controller 17 with the interface 14 between temperature controller with interface 13 and temperature sensor between temperature controller.By the Temperature Setting button 23 on temperature controller 17, digital selection key 18, raises button 19, lowers button 20, can set the temperature of heat transfer liquids, and can on temperature display 16, show.Pilot lamp 21 is used to refer to heat transfer liquids temperature and whether reaches design temperature, and heat transfer liquids temperature is not equal to design temperature, and pilot lamp 21 is shown as red light, and heat transfer liquids temperature reaches design temperature, and pilot lamp 21 is shown as green light.The output terminal concatenation operation amplifier 1 of electric bridge, as a reverse voltage amplifier, voltage amplification factor can be by changing adjustable feedback resistance R
f24 and adjustable input resistance R
i25 size regulates, and the output voltage of electric bridge is amplified, then through operational amplifier 2 27 outputs as output buffer, on the digital voltmeter voltage display screen 30 of digital voltmeter 29, show.The range of digital voltmeter 29 can regulate by digital voltmeter range gear adjusting knob 32.
Specific experiment operation steps is:
(1) according to accompanying drawing connection line, according to semiconductor thermistor or metal thermo-sensitive resistance R
t4 resistances in temperature-measuring range, by adjustable arm resistance R
11, adjustable arm resistance R
22 and adjustable arm resistance R
33 size adjustment is suitable.
(2), by the Temperature Setting button 23 on temperature controller 17, digital selection key 18, raises button 19, lowers button 20, sets the temperature t of heat transfer liquids, i.e. semiconductor thermistor or metal thermo-sensitive resistance R
t4 temperature, until pilot lamp 21 becomes green light from red light, heat transfer liquids temperature reaches setting value.
(3) by changing adjustable feedback resistance R
f24 and adjustable input resistance R
iit is suitable that the voltage amplification factor of large young pathbreaker's operational amplifier 1 of 25 regulates, and it is suitable by digital voltmeter range gear adjusting knob 32, the range of digital voltmeter 29 to be regulated.By digital voltmeter voltage display screen 30, read the output voltage U of electric bridge
o(t), every uniform temperature, measure once, by data recording in table.
(4) draw U
o(t)～t curve, so just can pass through U
o(t) measure the temperature t of object under test.
(5) by suitably choosing adjustable arm resistance R
11, adjustable arm resistance R
22, adjustable arm resistance R
33, adjustable feedback resistance R
f24 and adjustable input resistance R
i25 value, the magnitude of voltage that can make digital voltmeter voltage display screen 30 show is just in time the celsius temperature scale of object under test.
Above structure of the present invention is set forth, but the not conditional intention of the embodiment that the present invention introduces, and within not deviating from the scope of purport of the present invention, the present invention can have multiple variation and modification.
Claims (2)
1. utilize an experimental provision for nonequilibrium bridge design resistance thermometer, specifically by adjustable arm resistance R
1, R
2, R
3and semiconductor thermistor or metal thermo-sensitive resistance R
trespectively as four brachium pontis of electric bridge, form an electric bridge, by variable voltage source, to electric bridge, provide power supply, the size of voltage source output voltage can regulate by knob, and can on voltage source voltage display screen, show, semiconductor thermistor or metal thermo-sensitive resistance are placed in the glass flume of one end sealing, it is characterized in that: bath of glass cell wall adopts double-decker, centre is evacuated, to play good heat insulation effect, in glass flume, in heat transfer liquids, top part arranges semiconductor refrigerating plant, be used for Cooling Heat Transfer liquid, part arranges a heating arrangement on the lower, be used for heating heat transfer liquids, center section arranges a temperature sensor, be used for measuring the temperature of heat transfer liquids, semiconductor cooling device, heating arrangement and temperature sensor are connected with temperature controller by interface respectively, by the button on temperature controller, can set the temperature of heat transfer liquids.
2. the experimental provision that utilizes nonequilibrium bridge design resistance thermometer according to claim 1, is characterized in that: the output terminal concatenation operation amplifier one of electric bridge, as a reverse voltage amplifier, voltage amplification factor can be by changing adjustable feedback resistance R
fand adjustable input resistance R
isize regulate, the output voltage of electric bridge is amplified, then through operational amplifier two outputs as output buffer, on the voltage display screen of digital voltmeter, shows, by suitably choosing arm resistance, adjustable feedback resistance R
fand adjustable input resistance R
ivalue, can make the magnitude of voltage that the voltage display screen of digital voltmeter shows is just in time the celsius temperature scale of object under test.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410258214.9A CN104064076A (en) | 2014-06-04 | 2014-06-04 | Experimental facility using unbalanced bridge to design electrical resistance thermometer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410258214.9A CN104064076A (en) | 2014-06-04 | 2014-06-04 | Experimental facility using unbalanced bridge to design electrical resistance thermometer |
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| Publication Number | Publication Date |
|---|---|
| CN104064076A true CN104064076A (en) | 2014-09-24 |
Family
ID=51551760
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|---|---|---|---|
| CN201410258214.9A Pending CN104064076A (en) | 2014-06-04 | 2014-06-04 | Experimental facility using unbalanced bridge to design electrical resistance thermometer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104504974A (en) * | 2014-12-22 | 2015-04-08 | 常州大学 | Experiment instrument for designing and developing single-chip microcomputer |
| CN107504983A (en) * | 2017-09-06 | 2017-12-22 | 湖南航天机电设备与特种材料研究所 | Miniature fiber gyro Y waveguide drive circuit and half-wave voltage drift compensation method |
| CN117269296A (en) * | 2023-11-23 | 2023-12-22 | 南京分析仪器厂有限公司 | Internal convection thermomagnetic oxygen analyzer, magnetic device and detection circuit thereof |
-
2014
- 2014-06-04 CN CN201410258214.9A patent/CN104064076A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104504974A (en) * | 2014-12-22 | 2015-04-08 | 常州大学 | Experiment instrument for designing and developing single-chip microcomputer |
| CN107504983A (en) * | 2017-09-06 | 2017-12-22 | 湖南航天机电设备与特种材料研究所 | Miniature fiber gyro Y waveguide drive circuit and half-wave voltage drift compensation method |
| CN117269296A (en) * | 2023-11-23 | 2023-12-22 | 南京分析仪器厂有限公司 | Internal convection thermomagnetic oxygen analyzer, magnetic device and detection circuit thereof |
| CN117269296B (en) * | 2023-11-23 | 2024-01-30 | 南京分析仪器厂有限公司 | Internal convection thermomagnetic oxygen analyzer, magnetic device and detection circuit thereof |
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| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20140924 |
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| WD01 | Invention patent application deemed withdrawn after publication |