CN108169568A - Milliohm resistance measuring circuit - Google Patents
Milliohm resistance measuring circuit Download PDFInfo
- Publication number
- CN108169568A CN108169568A CN201810095226.2A CN201810095226A CN108169568A CN 108169568 A CN108169568 A CN 108169568A CN 201810095226 A CN201810095226 A CN 201810095226A CN 108169568 A CN108169568 A CN 108169568A
- Authority
- CN
- China
- Prior art keywords
- resistance
- voltage
- circuit
- constant
- measured
- 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.)
- Pending
Links
- 238000005259 measurement Methods 0.000 claims abstract description 23
- 230000003321 amplification Effects 0.000 claims abstract description 11
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 11
- 238000012360 testing method Methods 0.000 claims description 8
- 230000005611 electricity Effects 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000004832 voltammetry Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention discloses Milliohm resistance measuring circuits, it is connected and composed by basic constant-current source circuit, expansion current circuit and amplification with display circuit；Using four-line measurement, then measured resistance terminal voltage is amplified, measured resistance numerical value is shown after A/D is converted by measured resistance with constant current during measurement；Circuit of the present invention is simple, and device used is cheap, and high-precision, high stability is exempted to debug, and body is light in a small amount, and it is convenient to measure, cost-effective, measurement range 0-2000m Ω, 0.1 m Ω of resolution ratio.
Description
Technical field
The present invention relates to a kind of for accurately measuring the measuring circuit of Milliohm resistance, using voltammetry and four-line measurement
The small valued resistor of milliohm grade.
Background technology
In scientific experiment or engineering in practice, it is often necessary to all kinds of low resistances（≤1Ω）It is accurately measured, such as big work(
The resistance that rate motor, transformer are wound is tested, to check that multi cord whether there is strand broking；High-current switch, terminal
Whether the contact resistance of row meets the requirements；Quality supervision department is to factory（Quotient）Family's production or the cable material sold, section
Whether meet national standard and carry out accurate measurement etc..The measuring method of current low resistance is using double bridge, such as Fig. 1 institutes
Show, principle is：The measured resistance Rx and precision resistance R2 of known resistance value is formed into double bridge, by pushing button S observations
Whether galvanometer refers to 0 to judge whether electric bridge balances, and the resistance value of each shelves resistance of R2 is constantly adjusted, until galvanometer refers to 0.Quilt
Measuring resistance Rx is equal to the sum of resistance value of each shelves resistance of R2.I.e. bridge balance when Rx=R2.The drawback is that：Cumbersome, precision takes
Certainly in the precision of known resistance, reading is inconvenient, and equipment is heavy, and power consumption is larger when surveying milliohm grade small valued resistor.
Invention content
The purpose of the present invention is：A kind of Milliohm resistance measuring circuit is designed, circuit is simple, and device used is cheap,
In high precision, high stability is exempted to debug, and body is light in a small amount, and it is convenient to measure, cost-effective.
The principle of the present invention is：Based on voltammetry, foundation is：If the electric current for flowing through measured resistance is I, terminal voltage U,
Then measured resistance Rx=U/I；In order to reduce variable number, from calculating, take and flow through the electric current I of measured resistance for certain value,
Just monodrome linear relationship proportional between resistance terminal voltage U in this way and its resistance value must arrive electricity by measuring resistance terminal voltage
Resistance value；Such as when taking constant current Is=1A, the voltage value measured is equal to resistance value；When taking constant current Is=0.1A, on resistance
10 times of voltage amplification after numerical value be equal to measured resistance value；Obviously, the bigger sensitivity of On The Current Value is higher but more power-consuming,
Sensitivity is higher in order to balance and economizes on electricity（Convenient for battery powered）Two factors, this circuit take Is=0.1A.
The present invention technical solution be：The Milliohm resistance measuring circuit is by basic constant-current source circuit, expansion current circuit
It is connected and composed with amplification with display circuit；Using four-line measurement, during measurement with high precision, high stability constant current pass through by
Then measuring resistance amplifies measured resistance terminal voltage, measured resistance numerical value is shown after A/D is converted；Physical circuit connection is as follows：
Constant pressure source IC0（Model REF3025）Input termination power+Vcc, output terminal V0 series resistances R0 is followed by B points, and GND ends hang
Floating ground, meets amplifier IC1（Model OPA335）Output terminal, amplifier IC1 is connected into voltage follower, inverting input（-）Connect it
Output terminal, in-phase input end（+）B points are connect, B point series resistances Rn is followed by E points；Amplifier IC2（Model OPA335）It is connected into and compares
Device, in-phase input end（+）B points are connect, output terminal series resistance R1 is followed by Darlington triode TR（Model TIP122）Base
Pole, inverting input（-）The emitter of triode TR is connect, the collector of triode TR meets+Vcc, the in addition transmitting of triode TR
Pole series resistance Rs is followed by E points；Measured resistance Rx mono- terminates E points and the in-phase input end of amplifier IC3 is followed by through resistance R2（+）,
The in-phase input end of IC3（+）One end of connecting resistance R5 simultaneously, the other end ground connection of resistance R5, another termination of measured resistance Rx
Ground and the inverting input that amplifier IC3 is followed by through resistance R3（-）, the inverting input of IC3（-）Simultaneously connecting resistance R4 to its export
End, the output of IC3 terminate the analog voltage input Vi, voltmeter head VM of commercially available four and half LED digital display voltage meter heads VM
A/D conversion circuits are included, when inputting 0-2000mV voltages, display 0-1999.9.
Using the four lines measuring method, two testing current line I+, I- and connection amplifying circuit including connection constant-current source output
Two voltage tester lines V+, V- of input；Before measurement, two testing current lines and voltage tester line are coupled on Rx, make I
+, V+ and I-, V- be in the same side of measured resistance respectively, and make every effort to make voltage tester line V+, V- close proximity to measured resistance portion
Point；During measurement, measurement key is pressed, power supply is connected, and 0.1A high-accuracy and constant constant currents are passed through to measured resistance, then will be ohmically
Voltage accurately 10 times of amplification, according to measurement range 0-2000m Ω, then 0-2000mV of amplifying circuit output voltage range, is tested
The resistance value of resistance is just shown (0-1999.9m Ω) by commercially available four and half high-precisions LED digital voltage gauge outfits.
The beneficial effects of the invention are as follows：
1st, Milliohm resistance measuring circuit is small, light-weight, at low cost, can both be battery powered, and can also be powered by power grid, consumption
Electricity saves, and test operation is simple, and precision is high, and test result number shows direct-reading.
2nd, it using four-line measurement, excludes to measure the influence of line resistance and contact resistance, can replace completely with both arms electricity
Bridge measures the conventional method of low resistance, is the renewal product of traditional double bridge.
3rd, 0-2000 m Ω of measurement range of Milliohm resistance measuring circuit, 0.1 m Ω of resolution ratio, better than double bridge
Function and precision, suitable for production scene, laboratory and field work place use.
Description of the drawings
Fig. 1 is existing double bridge schematic diagram；
Fig. 2 is the circuit diagram of the present invention；
Fig. 3 is the four-line measurement wiring diagram of the present invention.
In figure：1 is basic constant-current source circuit；2 is expand current circuit；3 be amplification and display circuit.
Specific embodiment
The technical solution further illustrated the present invention with reference to the accompanying drawings and examples, but be not to be construed as to technical side
The limitation of case.
As shown in Fig. 2, 1 in Fig. 2 is basic constant-current source circuit, the constant current of 10mA is generated；High-accuracy and constant potential source IC0
（Model REF3025）Input termination power+Vcc, output terminal V0 series resistances R0 is followed by B points, and GND ends suspend, and connect amplifier
IC1（Model OPA335）Output terminal, amplifier IC1 is connected into voltage follower, inverting input（-）Its output terminal is connect, together
Phase input terminal（+）B points are connect, B point series resistances Rn is followed by E points.
As shown in Fig. 2, the electric current of basic constant-current source is expanded 9 times 2 to expand current circuit in Fig. 2（90mA）；Wherein amplifier
IC2（Model OPA335）It is connected into comparator, in-phase input end（+）B points are connect, output terminal series resistance R1 is followed by Darlington three
Pole pipe TR（Model TIP122）Base stage, inverting input（-）Connect the emitter of triode TR；The collector of triode TR connects
+ Vcc, in addition the emitter series resistance Rs of triode TR be followed by E points.
As shown in Fig. 2, 3 being amplification and display circuit in Fig. 2, the terminal voltage of measured resistance is amplified 10 times, is converted through A/D
And number display；Measured resistance Rx mono- terminates E points and is followed by amplifier IC3 through resistance R2（Model OPA335）In-phase input end
（+）, the in-phase input end of amplifier IC3（+）One end of connecting resistance R5 simultaneously, the other end ground connection of resistance R5；Measured resistance Rx's
The other end is grounded and the inverting input of amplifier IC3 is followed by through resistance R3（-）, the inverting input of IC3（-）Connecting resistance R4 simultaneously
To its output terminal, the output of IC3 terminates the analog voltage input of commercially available four and half high-precisions LED digital display voltage meter heads VM
Vi, voltmeter head VM include A/D conversion circuits, when inputting 0-2000mV voltages, display 0-1999.9.
1 is basic constant-current source circuit in Fig. 2, and high-accuracy and constant constant current, is produced using high-accuracy and constant potential source IC0 in order to obtain
It is raw, the output terminal V0 output voltages of IC0（Relative to its GND end）For 2.500V, voltage comparator is connected by amplifier IC1-1, by
" empty short " principle of amplifier, A points（That is GND ends）With B point equipotentials, so between V0 and B points voltage be 2.500V, series resistance
Constant current I1, I1=2.5/R0 are obtained after R0；Because the maximum output current of IC0 is 25mA, I1=10 mA are taken here, then
Take R0=250 Ω precision resistances.
2 is expand current circuit in Fig. 2, by the current expansion of constant-current source, make I4=90 mA；IC2 is connected into voltage comparator, drives
The conducting state of dynamic Darlington triode TR flows to expand；By " void is disconnected " principle of amplifier, amplifier IC1, IC2 input terminal is flowed into
Electric current I2 ≈ 0, I3 ≈ 0（All at pA grades）, so I0=I1=10 mA；Again by " empty short " principle of amplifier, C points and D points etc. are electric
Position, so voltage I0 × Rn=I4 × Rs, wherein I0=10 mA, I4=90 mA, then Rn=9Rs；After electric current I0 and I4 confluences
Obtain Is, Is=I0+I4=100mA, i.e. 0.1A.
The 3 terminal voltage amplification and display circuit, amplifier IC3 for measured resistance Rx is connected into in-phase amplification circuit, takes R2 in Fig. 2
=R3, R4=9R3, then Au=1+R4/R3=10 times of voltage amplification factor；100mA constant currents flow through measured resistance Rx in this way
When the pressure drop that generates be 100Rx（Unit mV）, the voltage after 10 times of amplification is 1000Rx（Unit mV）, corresponding to Rx measurement ranges
Voltage change range during 0-2000m Ω is 0-2000mV, selects 0-2000mV of input voltage, indication range for 0-
1999.9 commercially available accurate voltage gauge outfit, the number of display is the m Ω values of measured resistance, and resolution ratio is 0.1m Ω.
As shown in figure 3, for four-line measurement wiring diagram, exclude to measure line resistance and contact resistance using four-line measurement
It influences；Two voltage testers of two testing current line I+, I- and connection amplifying circuit input including connection constant-current source output
Line V+, V-；Before measurement, two testing current lines and voltage tester line are coupled on Rx, I+, V+ and I-, V- is made to locate respectively
In the same side of measured resistance, and make every effort to make voltage tester line V+, V- close proximity to measured resistance part.
As shown in Fig. 2, used resistance R0, Rn, Rs, R2, R3, R4 are precision resistance；High-accuracy and constant potential source IC0 is selected
Model REF3025 is selected, output voltage 2.500V, deviation is 10-4Magnitude, 50ppm/ DEG C of temperature drift；IC1, IC2 and IC3 are selected
The rail-to-rail amplifier OPA335 produced with CMOS technology, input impedance is high, 109Ω magnitudes, offset voltage only 5 μ V, zero drift
Only 0.05 μ V/ DEG C are moved, are suitble to single supply power supply.
Claims (4)
1. Milliohm resistance measuring circuit, the Milliohm resistance measuring circuit is by basic constant-current source circuit, expansion current circuit and amplification
It is connected and composed with display circuit；Using four-line measurement, with constant current by measured resistance during measurement, then by measured resistance
Terminal voltage is amplified, and measured resistance numerical value is shown after A/D is converted；It is characterized in that its physical circuit connection is as follows：Constant pressure source IC0
（Model REF3025）Input termination power+Vcc, output terminal V0 series resistances R0 is followed by B points, and GND ends suspend ground, connect fortune
Put IC1（Model OPA335）Output terminal, amplifier IC1 is connected into voltage follower, inverting input（-）Its output terminal is connect, together
Phase input terminal（+）B points are connect, B point series resistances Rn is followed by E points；Amplifier IC2（Model OPA335）It is connected into comparator, same to phase
Input terminal（+）B points are connect, output terminal series resistance R1 is followed by Darlington triode TR（Model TIP122）Base stage, reverse phase is defeated
Enter end（-）The emitter of triode TR is connect, the collector of triode TR meets+Vcc, in addition the emitter series resistance of triode TR
Rs is followed by E points；Measured resistance Rx mono- terminates E points and the in-phase input end of amplifier IC3 is followed by through resistance R2（+）, IC3's is same mutually defeated
Enter end（+）One end of connecting resistance R5 simultaneously, the other end ground connection of resistance R5, the other end of measured resistance Rx are grounded and through resistance R3
It is followed by the inverting input of amplifier IC3（-）, the inverting input of IC3（-）Connecting resistance R4 is to its output terminal, the output of IC3 simultaneously
The analog voltage input Vi of commercially available four and half LED digital display voltage meter heads VM is terminated, voltmeter head VM includes A/D conversion electricity
Road, when inputting 0-2000mV voltages, display 0-1999.9.
2. Milliohm resistance measuring circuit according to claim 1, it is characterized in that the measuring circuit uses the four lines measuring method,
Two voltage tester line V+ of two testing current line I+, I- and connection amplifying circuit input including connection constant-current source output,
V-；Before measurement, two testing current lines and voltage tester line are coupled on Rx, I+, V+ and I-, V- are made to be in respectively tested
The same side of resistance, and make every effort to make voltage tester line V+, V- close proximity to measured resistance part；During measurement, measurement key is pressed, electricity
Source is connected, and 0.1A high-accuracy and constant constant currents are passed through to measured resistance, ohmically voltage is accurately then amplified 10 times, according to survey
Range 0-2000m Ω are measured, then 0-2000mV of amplifying circuit output voltage range, the resistance value of measured resistance is just by commercially available four and half
LED digital voltage gauge outfits are shown (0-1999.9m Ω).
3. Milliohm resistance measuring circuit according to claim 1, it is characterized in that：Resistance R0, Rn, Rs, R2, R3, R4 are equal
For precision resistance；Constant pressure source IC0 selects model REF3025, and it is OPA335 that amplifier IC1, IC2 and IC3, which select model,.
4. Milliohm resistance measuring circuit according to claim 3, it is characterized in that：Resistance Rn=9Rs, R4=9R3, R4=
R5。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810095226.2A CN108169568A (en) | 2018-01-31 | 2018-01-31 | Milliohm resistance measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810095226.2A CN108169568A (en) | 2018-01-31 | 2018-01-31 | Milliohm resistance measuring circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108169568A true CN108169568A (en) | 2018-06-15 |
Family
ID=62512344
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810095226.2A Pending CN108169568A (en) | 2018-01-31 | 2018-01-31 | Milliohm resistance measuring circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108169568A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110927465A (en) * | 2019-11-26 | 2020-03-27 | 深圳供电局有限公司 | Direct current resistance measuring circuit and device |
| CN110940858A (en) * | 2018-09-21 | 2020-03-31 | 浙江绍兴苏泊尔生活电器有限公司 | Detection circuit and method for contact resistance |
| CN114325114A (en) * | 2021-11-29 | 2022-04-12 | 云南电网有限责任公司昆明供电局 | Double-end grounding loop resistance testing method of disassembly-free grounding wire |
| WO2023040221A1 (en) * | 2021-09-17 | 2023-03-23 | 深圳市中兴微电子技术有限公司 | Apparatus and method for testing change in resistance value of solder joint |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1749763A (en) * | 2005-11-03 | 2006-03-22 | 北京科技大学 | Method and device for detecting resistance |
| CN201378188Y (en) * | 2009-04-23 | 2010-01-06 | 中南林业科技大学 | Numerically-controlled resistance measurement device |
| JP2012168105A (en) * | 2011-02-16 | 2012-09-06 | Azbil Corp | Four wire temperature measuring resistor input circuit |
| CN106383272A (en) * | 2015-07-30 | 2017-02-08 | 北京电子工程总体研究所 | High-precision small resistor resistance measurement circuit |
| CN207992320U (en) * | 2018-01-31 | 2018-10-19 | 淮安信息职业技术学院 | Milliohm resistance measuring circuit |
-
2018
- 2018-01-31 CN CN201810095226.2A patent/CN108169568A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1749763A (en) * | 2005-11-03 | 2006-03-22 | 北京科技大学 | Method and device for detecting resistance |
| CN201378188Y (en) * | 2009-04-23 | 2010-01-06 | 中南林业科技大学 | Numerically-controlled resistance measurement device |
| JP2012168105A (en) * | 2011-02-16 | 2012-09-06 | Azbil Corp | Four wire temperature measuring resistor input circuit |
| CN106383272A (en) * | 2015-07-30 | 2017-02-08 | 北京电子工程总体研究所 | High-precision small resistor resistance measurement circuit |
| CN207992320U (en) * | 2018-01-31 | 2018-10-19 | 淮安信息职业技术学院 | Milliohm resistance measuring circuit |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110940858A (en) * | 2018-09-21 | 2020-03-31 | 浙江绍兴苏泊尔生活电器有限公司 | Detection circuit and method for contact resistance |
| CN110927465A (en) * | 2019-11-26 | 2020-03-27 | 深圳供电局有限公司 | Direct current resistance measuring circuit and device |
| CN110927465B (en) * | 2019-11-26 | 2022-09-02 | 深圳供电局有限公司 | Direct current resistance measuring circuit and device |
| WO2023040221A1 (en) * | 2021-09-17 | 2023-03-23 | 深圳市中兴微电子技术有限公司 | Apparatus and method for testing change in resistance value of solder joint |
| CN114325114A (en) * | 2021-11-29 | 2022-04-12 | 云南电网有限责任公司昆明供电局 | Double-end grounding loop resistance testing method of disassembly-free grounding wire |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108169568A (en) | Milliohm resistance measuring circuit | |
| CN204101635U (en) | A kind of microresistivity survey instrument and electronic product process units | |
| CN107390009B (en) | A kind of micro-current test device and method | |
| CN203164326U (en) | Digital display type detection device of resistor strain sensor | |
| CN204215023U (en) | Terminal charge parameter testing line | |
| CN202758003U (en) | DC resistance tester | |
| CN105785131A (en) | Testing device and method for low ohm chip resistors | |
| CN207992320U (en) | Milliohm resistance measuring circuit | |
| CN102590632A (en) | Insulation resistance test circuit for circuit board | |
| CN208013301U (en) | A kind of circuit board impedance device for fast detecting | |
| CN202582775U (en) | Temperature measuring circuit | |
| CN107505061A (en) | A kind of platinum resistance temperature measuring device in double-current source | |
| CN211652972U (en) | Linear scale ohmmeter based on constant current source | |
| CN210346590U (en) | Wireless static strain tester and wireless static strain test system | |
| CN205665382U (en) | Enlarged circuit that draws of difference mode signal | |
| CN104237642A (en) | Automatic hall resistivity testing method | |
| CN205642725U (en) | Resistance vacuum transmitter | |
| CN202393834U (en) | Precise ohmic internal resistance measurer for battery | |
| CN201166682Y (en) | Test circuit special for multimeter adaptive voltage cascade low-resistance | |
| CN204988943U (en) | High accuracy metal material fatigue damage test instrument | |
| CN106841751A (en) | A kind of voltage up-down quantitative determination circuits/devices | |
| CN202330515U (en) | Multi-measuring range current measurement parallel display unit | |
| CN109239514B (en) | Short circuit and open circuit detection circuit of liquid level meter sensor | |
| CN103837811A (en) | High-resolution test device for transistor characteristic curve tracer | |
| CN208000337U (en) | A kind of balancing circuit |
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 | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20180615 |
|
| WD01 | Invention patent application deemed withdrawn after publication |