CN106989847A - Error correcting method in system of Pt-resistance - Google Patents
Error correcting method in system of Pt-resistance Download PDFInfo
- Publication number
- CN106989847A CN106989847A CN201710175753.XA CN201710175753A CN106989847A CN 106989847 A CN106989847 A CN 106989847A CN 201710175753 A CN201710175753 A CN 201710175753A CN 106989847 A CN106989847 A CN 106989847A
- Authority
- CN
- China
- Prior art keywords
- resistance
- rtd
- error
- measuring
- measurement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K15/00—Testing or calibrating of thermometers
- G01K15/005—Calibration
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention discloses the error correcting method in a kind of method system of Pt-resistance based on resistance ratios, the present invention uses excitation current source reverse flow technique, eliminates the influence of parasitic thermo-electromotive force and system drifting in the measuring loops such as RTD connector, analog switch；Analyze the measurement error that gain resistor is mismatched in amplifying circuit and lead resistance is introduced, it is proposed that correction function form, demarcated by amplifying circuit common-mode rejection ratio and lead resistance measures determination correction function parameter in real time.The present invention sets up functional relation and calculates each error coefficient by the analysis to each error in circuit structure, so that the resistance for measuring RTD is modified, test result indicates that：Temp measuring system is after error correction, and the accuracy of temperature survey is significantly improved.
Description
Technical field
The present invention relates to field of temperature measurement, relate more specifically to a kind of be based in resistance ratios method system of Pt-resistance
Error correcting method.
Background technology
Temperature is the important parameter in daily life and production activity, is related to national economy, scientific research and social construction
Etc. each side, temperature information is accurately and efficiently obtained significant.In geologic prospect, environment measuring, industry spot multiple spot
The fields such as data acquisition, do not require nothing more than and realize high precision measuring temperature, also require that instrument is portable, in the wild or scene can be steady for a long time
Fixed work, and it is simple to operate, cost performance is high.With science and technology continuous progress, thermometry just towards high accuracy, it is low into
Originally, small integrated development.RTD is most accurate and most stable of temperature sensor, due to high-precision, preferably linear
The advantages of degree, splendid interchangeability and long-time stability, it is widely used in high-precision field of temperature measurement.
At present, high-precision thermal resistance method measurement temperature mainly uses the RTD of four-wire system to eliminate the measurement that lead is caused
Error.In precise temperature measurement system, resistance signal is converted to voltage signal, then amplified processing and modulus usually through bridge circuit
Converter is changed, and is eventually sent to single-chip microcomputer and is handled.But due to circuit components performance, environment temperature, RTD self-heating
The influence of effect, makes to exist during system testing gain resistor in larger error, and lead resistance and difference amplifier and mismatches
The accuracy of thermometric will be influenceed.
The content of the invention
For the degree of accuracy in the existing portable platinum resistance temperature measuring system mentioned in background technology it is not high the problem of, this
Invention uses four-wire system platinum resistance temperature sensor, devises a kind of portable high-accuracy thermometric electricity based on resistance ratios method
Road, and propose a kind of method of round-off error.
The technical solution adopted by the present invention is：
Contain multinomial error, the main common-mode error including on difference amplifier, lead error, parasitic thermoelectricity in temperature measurement circuit
Gesture error etc., wherein most importantly common-mode error, shadow of its size by difference degree between gain resistor on difference amplifier
Ring.The modification method of the error is：By the influence of each error term in analysis circuit, voltage ratio and RTD, ginseng are set up
The functional relation between resistance, lead resistance and analog switch conducting resistance is examined, the temperature measurement circuit is connected into measuring resistance
Case, regulation resistance box substitutes into above-mentioned function as true value to measure the measuring resistance of different resistances, using standard resistance box indicating value and closed
It is that repeatedly measurement composition multi head linear equation group, which can be solved, obtains each error term coefficient, finally gives the amendment of RTD in formula
Formula, so as to correct the resistance of RTD.
The operation principle of the temperature measurement circuit is：Four-wire system RTD is as temperature transducer, and high stable metal paper tinsel resistance is made
For reference resistance, both connect simultaneously is driven by constant-current source, by analog switch switching channel, analog-digital converter conversion RTD and
Voltage on reference resistance, sends to single-chip microcomputer with the voltage after will changing, single-chip microcomputer data are handled after again by platinum
The temperature that resistance is measured, which is sent to host computer, to be shown.
The beneficial effects of the invention are as follows：Using constant-current source unidirectional driving series connection RTD and reference resistance, effectively reduce
Error caused by parasitic electromotive force in lead resistance and circuit；Using high-resolution analog-digital converter and high stable metal paper tinsel electricity
Resistance improves the precision and stability of temp measuring system；By the analysis to each error in circuit structure, functional relation is set up simultaneously
Each error coefficient is calculated, so that the resistance for measuring RTD is modified, test result indicates that：Temp measuring system passes through error
After amendment, the accuracy of temperature survey is significantly improved.
Brief description of the drawings
Fig. 1 is the structure chart of high precision measuring temperature system；
Fig. 2 is the schematic diagram of constant-current source driving and switching circuit；
Fig. 3 is the schematic diagram of Pt Resistance Temperature Measuring Circuit；
Fig. 4 is error analysis schematic diagram；
Embodiment
The present invention will be described in further detail below in conjunction with the accompanying drawings.
As illustrated, Fig. 1 is the structure chart of high-precision platinum resistor temperature measuring system of the present invention, RTD is used as TEMP
Device, it is to be varied with temperature and changed and to be in the characteristic of certain functional relation carry out thermometric using resistance, by measuring its electricity
Resistance extrapolates testee temperature, here it is the operation principle of platinum resistance temperature sensor.High-precision platinum resistor temperature measuring system
Including：Precision constant current source drive circuit, analog switch switching circuit, voltage follower, the differential amplification electricity of Voltage-current conversion
Road, high stable metal paper tinsel resistance and analog-digital converter and single-chip microcomputer are constituted.
The analog switch switching circuit is low on-resistance, low-power consumption, binary channels DPDT cmos device, plays and cuts
Change the effect of constant-current source direction and selection amplification path；Voltage follower is ultra-low noise operational amplifier, defeated using amplifier
Enter the big characteristic of impedance, realize impedance matching；Differential amplifier circuit be by low noise, low distortion, super low-power consumption differential amplification
Device and gain resistor composition, gain resistor is the precision resistance of 4 0.1%, realizes that differential gain is configured；High stable metal paper tinsel electricity
Resistance is the high-accuracy resistance of 100 Ω that precision is 0.01%, and temperature drift coefficient is 0.05ppm；Analog-digital converter is 32 moulds of sigma-delta type
Number converter, it realizes digital filtering using high frequency multiplication oversampling technique, reduces the requirement filtered to sensor signal, passes through
Oversampling technique is used in combination with noise shaping and digital filtering technique, its effective resolution is improved；Single-chip microcomputer is
STM32 series mini processors, are the centers to thermometric Row control and data processing.
Fig. 2 is the precision constant current source drive circuit of Voltage-current conversion, is put using ultra-low noise, the computing of low imbalance
Large chip ADA4528 stablizes the constant-current source exported to provide, wherein R1=R2=100K, R3=R4=10K, is that precision is
0.1% resistance, R5=330 Ω, the constant-current source I=0.75mA of output.
Fig. 3 is Pt Resistance Temperature Measuring Circuit schematic diagram, and RTD is connected with reference resistance, and both threads are led in four-wire system RTD
Constant-current source, two are pressure-wire in addition, and circuit multiplication factor is designated as G；When constant-current source flows to reference resistance from RTD, amplification
The voltage of RTD is designated as Volt afterwards1, the voltage of reference resistance is designated as Volt2；When constant-current source from reference resistance flows to RTD
When, the voltage of RTD is designated as Volt after amplification3, the voltage of reference resistance is designated as Volt4；It is parasitic on RTD path in circuit
Electromotive force is designated as EMF1, offset drift is designated as OFFSET1, parasitic electromotive force is designated as EMF on reference resistance path2, offset drift note
For OFFSET2：
Volt1=G (I × RPT+EMF1)+OFFSET1 (1)
Volt2=G (I × Rref+EMF2)+OFFSET2 (2)
Volt3=G (- I × RPT+EMF1)+OFFSET1 (3)
Volt4=G (- I × Rref+EMF2)+OFFSET2 (4)
It can be obtained according to above formula：Thus formula can be seen that assuming that electricity
Road multiplication factor G is constant and during not by measured influenceing, and can eliminate in circuit parasitic on lead by constant-current source commutation method
The influence of electromotive force and offset drift to measurement RTD resistance, the resistance of RTD and the voltage ratio of measurement and reference electricity
Resistance is relevant.
Fig. 4 be error analysis schematic diagram, RF1=RF2=250 Ω, RG1=RG2=2K Ω, be 0.1% precision electricity
Resistance, constitutes simple external feedback network, realizes that differential gain is configured；Because the resistance of these feedback resistances is not fully matched,
So that circuit multiplication factor G is influenceed by feedback resistance resistance, ifWith reference to above-mentioned analysis
Analysis of the step to circuit differential amplified voltage, if voltage ratio is M, then can obtain formula (5)：
As can be seen here, due on difference amplifier gain resistor mismatch and have error coefficient β's to voltage ratio
Influence, if β is bigger, the deviation of RTD resistance is then bigger, and the degree of accuracy is lower.
However, the error of temp measuring system is not only influenceed by the difference degree between gain resistor, also by lead electricity
Resistance and the influence of analog switch conducting resistance.In order to analyze the influence of each error, the function expression of RTD is re-established.
As shown in figure 4, RPTAnd RrefThe resistance of RTD and reference resistance, LP are represented respectivelyA、LPB、LPCAnd LPDIt is on RTD respectively
Lead resistance, LRA、LRB、LRCAnd LRDIt is the lead resistance on reference resistance respectively.RonA、RonBIt is leading on analog switch
Be powered resistance (relay or CMOS multiplexer), OFFA、OFFB、OFFC、OFFDThe bias voltage of output amplifier, due to putting
The input impedance of big device is big, can ignore in the influence of sampling end wires and conducting resistance.
Similarly, the first step is the voltage that RTD is measured when electric current is flowed on reference resistance from RTD, inputs mould
The RTD voltage of number converter is designated as Vin1, expression formula is as follows：
Vin1=α { (I × RPT+OFFB-OFFA)+β[I(LPD+LRA+Rref+
LRD+RonB)+OFFB]}+OFFC-OFFD (6)
Second step is the voltage that reference resistance is measured when electric current is flowed on reference resistance from RTD, and input modulus turns
The reference resistance voltage of parallel operation is designated as Vin2, expression formula is as follows：
Vin2=α { (I × Rref+OFFB-OFFA)+β[I(LRD+RonA)+
OFFB]}+OFFC-OFFD (7)
3rd step is the voltage that RTD is measured when electric current is flowed on RTD from reference resistance, inputs analog-to-digital conversion
The RTD voltage of device is designated as Vin3, expression formula is as follows：
Vin3=α { (- I × RPT+OFFB-OFFA)+β[I(RPT+LRA+
RonA)+OFFB]}+OFFC-OFFD (8)
4th step is the voltage that reference resistance is measured when electric current is flowed on RTD from reference resistance, and input modulus turns
The reference resistance voltage of parallel operation is designated as Vin4, expression formula is as follows：
Vin4=α { (- I × Rref+OFFB-OFFA)+β[I(Rref+LRA+
LPD+RPT+LPA+RonA)+OFFB]}+OFFC-OFFD(9)
If voltage ratioHad according to formula (6)~(9)：
Wherein：
ΔL1=LPA-LPD-LRA-LRD
ΔL2=LPA+LPD+LRA-LRD
ΔRon=RonA-RonB
According to the physical length of lead in circuit, lead resistance can be measured directly, or by its with β and REF as not
Know error coefficient, substitution formula (10), which sets up equation, can also solve.According to formula (10), release voltage ratio and resistance and
Relational expression comprising error term is as follows：
By analysis, due to every error in circuit, resistance ratio is complicated all the more with voltage ratio relational expression, closes
It is that error term coefficient present in formula is bigger, RPTDeviation it is then bigger, the degree of accuracy is lower, it is therefore desirable to round-off error factor beta,
The value of reference resistance and lead resistance.The method of amendment is：RTD is replaced with calibrated measuring resistance, the system half-mark
Quasi- resistance obtains voltage ratio M, using calibrated measuring resistance as RTD true value RPT, Rref, lead resistance, β are unknown ginseng
Number, measures the measuring resistance of multiple different resistances, substitutes into formula (10) composition multi head linear equation group and solves correlated error
Coefficient, by error term coefficient substitute into formula (11), obtain the correction value of RTD resistance.
Experimental verification：Circuit board measures the precision resistance of different resistances, it is ensured that under same experimental conditions, precision resistance is soaked
Not in small-sized oil bath, and real-time temperature control is carried out to oil bath, by measuring for a long time, test result display is existing without substantially drift
As thermometric precision is better than 1.6mK；After error correcting method, the temperature survey accuracy of temp measuring system is significantly increased,
In 0~500 Ω scopes, the measuring resistance resistance that temp measuring system is measured after amendment differs maximum with true value and only has 0.00295 Ω, temperature
Coefficient is floated in ± below 15ppm, is calculated with the Ω of maximum absolute error 0.00295, and correspondence ITS-90 standard phasing meters use RTD
At 0 DEG C 3850 × 10-6/ DEG C Calculation of Sensitivity, revised maximum temperature detection relative error is 0.007 DEG C.
The system of Pt-resistance based on resistance ratios method and the error correcting method of proposition designed with reference to the present invention, no
High precision measuring temperature can be only realized, and it is low in energy consumption, exquisite portable, area is only 120mm × 77mm, with high-precision, uncertain
The characteristics of degree small, inexpensive, small integrated, meet in the neck such as geologic prospect, environment measuring, industry spot multi-point data acquisition
The thermometric requirement in domain, can long-time stable work, and simple to operate, cost performance is high, it is adaptable to portable high-accuracy temperature measurer,
Digital temperature meter, the development of resistance temperature marking apparatus and intelligent high precision measuring temperature quasi-instrument.
Claims (2)
1. the error correcting method in system of Pt-resistance, the temp measuring system of this method is included based on Voltage-current conversion
Constant current source driving circuit, analog switch, voltage follower, difference amplifier, high stable state reference resistance, sigma-delta type analog-to-digital conversion
Device, microcontroller, it is characterised in that common-mode error, reference resistance, lead resistance and analog switch conducting resistance in analysis circuit
Influence to measurement, the functional relation set up between RTD and every error, with the standard electric of calibrated different resistances
Resistance substitutes RTD, and the true value of RTD is designated as with the measuring resistance resistance of demarcation, true value is substituted into functional relation, repeatedly
Measurement composition multi head linear equation group, which can be solved, obtains each error term coefficient, and error coefficient is substituted into correction function in real time,
The amendment of RTD resistance is realized, the purpose for improving thermometric accuracy is reached.
2. error correcting method according to claim 1, it is characterised in that common-mode error, ginseng in analysis analysis circuit
When examining the influence of resistance, lead resistance and analog switch conducting resistance to measurement, RTD excitation electricity is realized using analog switch
Stream commutation, by carrying out the one-shot measurement of RTD both end voltage under being encouraged in forward current, is completed under backward current excitation
The measurement again of RTD both end voltage, measurement result will sum twice, eliminate parasitic thermo-electromotive force and system in measuring loop
The influence of drift.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710175753.XA CN106989847B (en) | 2017-03-22 | 2017-03-22 | Error correcting method in system of Pt-resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710175753.XA CN106989847B (en) | 2017-03-22 | 2017-03-22 | Error correcting method in system of Pt-resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106989847A true CN106989847A (en) | 2017-07-28 |
| CN106989847B CN106989847B (en) | 2019-09-06 |
Family
ID=59412892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710175753.XA Active CN106989847B (en) | 2017-03-22 | 2017-03-22 | Error correcting method in system of Pt-resistance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106989847B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107702822A (en) * | 2017-09-21 | 2018-02-16 | 中国计量大学 | A kind of multichannel quick high accuracy temp measuring system based on intersection polling mechanism |
| CN109870242A (en) * | 2017-12-01 | 2019-06-11 | 爱思开海力士有限公司 | Digital temperature sensing circuit |
| CN109870487A (en) * | 2019-02-18 | 2019-06-11 | 中国石油天然气集团有限公司 | A kind of calibrating conductor resistance compensation method of conductivity sensor and device and system |
| CN110488889A (en) * | 2019-07-11 | 2019-11-22 | 湖南明康中锦医疗科技发展有限公司 | A kind of Breathing Suppotion device temperature collection control method and system |
| CN111380624A (en) * | 2018-12-27 | 2020-07-07 | 瑞昱半导体股份有限公司 | Temperature calculation parameter providing circuit, temperature calculation parameter providing method, and temperature monitoring method |
| CN112798129A (en) * | 2020-12-30 | 2021-05-14 | 浙江启尔机电技术有限公司 | Temperature measuring device |
| CN114720009A (en) * | 2022-06-09 | 2022-07-08 | 中国船舶重工集团公司第七0七研究所 | Digital high-precision temperature measurement system and method for relative gravimeter |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100002747A1 (en) * | 2008-07-03 | 2010-01-07 | Bosch Enrique Company | System and method for n'th order digital piece-wise linear compensation of the variations with temperature of the non-linearities for high accuracy digital temperature sensors in an extended temperature range |
| CN102539925A (en) * | 2010-12-30 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | High-accuracy dynamic testing method for sensor |
| CN102829888A (en) * | 2011-06-15 | 2012-12-19 | 上海电器科学研究院 | Method for eliminating three-wire heating resistor measurement errors |
| CN204085729U (en) * | 2014-09-26 | 2015-01-07 | 江南大学 | A kind of high-precision platinum resistance temperature measurement mechanism |
| CN105784176A (en) * | 2016-05-25 | 2016-07-20 | 北京先驱威锋技术开发公司 | Temperature measuring system and method based on platinum resistor |
| CN106404207A (en) * | 2016-11-08 | 2017-02-15 | 辽宁师范大学 | Platinum resistance-based wide-range high-precision temperature measuring instrument and measuring method thereof |
-
2017
- 2017-03-22 CN CN201710175753.XA patent/CN106989847B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100002747A1 (en) * | 2008-07-03 | 2010-01-07 | Bosch Enrique Company | System and method for n'th order digital piece-wise linear compensation of the variations with temperature of the non-linearities for high accuracy digital temperature sensors in an extended temperature range |
| CN102539925A (en) * | 2010-12-30 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | High-accuracy dynamic testing method for sensor |
| CN102829888A (en) * | 2011-06-15 | 2012-12-19 | 上海电器科学研究院 | Method for eliminating three-wire heating resistor measurement errors |
| CN204085729U (en) * | 2014-09-26 | 2015-01-07 | 江南大学 | A kind of high-precision platinum resistance temperature measurement mechanism |
| CN105784176A (en) * | 2016-05-25 | 2016-07-20 | 北京先驱威锋技术开发公司 | Temperature measuring system and method based on platinum resistor |
| CN106404207A (en) * | 2016-11-08 | 2017-02-15 | 辽宁师范大学 | Platinum resistance-based wide-range high-precision temperature measuring instrument and measuring method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 胡鹏程等: "高精度铂电阻测温系统", 《光学精密工程》 * |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107702822A (en) * | 2017-09-21 | 2018-02-16 | 中国计量大学 | A kind of multichannel quick high accuracy temp measuring system based on intersection polling mechanism |
| CN107702822B (en) * | 2017-09-21 | 2019-05-10 | 中国计量大学 | A kind of multichannel quick high accuracy temp measuring system based on intersection polling mechanism |
| CN109870242A (en) * | 2017-12-01 | 2019-06-11 | 爱思开海力士有限公司 | Digital temperature sensing circuit |
| US11099080B2 (en) | 2017-12-01 | 2021-08-24 | SK Hynix Inc. | Digital temperature sensing circuit |
| CN109870242B (en) * | 2017-12-01 | 2022-01-07 | 爱思开海力士有限公司 | Digital temperature sensing circuit |
| CN111380624A (en) * | 2018-12-27 | 2020-07-07 | 瑞昱半导体股份有限公司 | Temperature calculation parameter providing circuit, temperature calculation parameter providing method, and temperature monitoring method |
| CN111380624B (en) * | 2018-12-27 | 2021-12-21 | 瑞昱半导体股份有限公司 | Temperature calculation parameter providing circuit, temperature calculation parameter providing method, and temperature monitoring method |
| CN109870487A (en) * | 2019-02-18 | 2019-06-11 | 中国石油天然气集团有限公司 | A kind of calibrating conductor resistance compensation method of conductivity sensor and device and system |
| CN110488889A (en) * | 2019-07-11 | 2019-11-22 | 湖南明康中锦医疗科技发展有限公司 | A kind of Breathing Suppotion device temperature collection control method and system |
| CN112798129A (en) * | 2020-12-30 | 2021-05-14 | 浙江启尔机电技术有限公司 | Temperature measuring device |
| CN114720009A (en) * | 2022-06-09 | 2022-07-08 | 中国船舶重工集团公司第七0七研究所 | Digital high-precision temperature measurement system and method for relative gravimeter |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106989847B (en) | 2019-09-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106989847B (en) | Error correcting method in system of Pt-resistance | |
| CN105651412B (en) | A kind of measurement method and measuring circuit for PT1000 temperature sensors | |
| CN103837253B (en) | A kind of CMOS temperature transmitter | |
| CN202928716U (en) | High precision intelligent temperature measurement circuit | |
| CN109489853A (en) | High-precision multi-path platinum resistor temperature measuring module and method based on constant-current source | |
| CN104344908B (en) | A kind of three-wire system thermal resistance measuring circuit | |
| CN101915869A (en) | Method for reducing measuring error introduced by excitation signal amplitude fluctuations and implementation device | |
| CN106344039A (en) | Weak signal precision measurement device and method of bio-sensors | |
| CN109375291A (en) | A kind of temperature and air pressure suitable for sonde and humidity measuring instrument and method | |
| CN108151903A (en) | High Precision Low Temperature drift temp measuring system and its measuring method based on three-wire system PT100 | |
| CN102645582A (en) | High-accuracy frequency measurement system | |
| CN104483033B (en) | A kind of CMOS temperature transmitter circuit of wide temperature range | |
| CN108680616A (en) | A kind of humidity sensing device and method of digitized processing | |
| Fasoli et al. | A general circuit for resistive bridge sensors with bitstream output | |
| CN101887092A (en) | Resistance measurement method with wide temperature range, wide measurement range, high precision and low cost | |
| CN208902293U (en) | A kind of PT100 temperature measurement circuit | |
| CN214041538U (en) | Current and voltage detection circuit based on single chip microcomputer | |
| CN205748693U (en) | A kind of high accuracy number thermometer | |
| CN206339316U (en) | Multi-channel temperature measurement device | |
| CN111208346B (en) | Small signal voltage measuring device and method | |
| CN110440945B (en) | High-precision low-temperature drift discrete type double-matching constant current source temperature measuring circuit | |
| CN211206616U (en) | Hall current sensor with temperature compensation | |
| CN210005595U (en) | thermal resistance four-wire system real-time measuring circuit | |
| CN211013290U (en) | High-precision low-temperature-drift discrete double-matching constant-current source temperature measurement circuit | |
| CN103217570A (en) | Tunneling magneto resistive (TMR) self-temperature-compensation digital current sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |