CN102707149A - Integrating contact resistance measuring system and method - Google Patents

Integrating contact resistance measuring system and method Download PDF

Info

Publication number
CN102707149A
CN102707149A CN2012102183629A CN201210218362A CN102707149A CN 102707149 A CN102707149 A CN 102707149A CN 2012102183629 A CN2012102183629 A CN 2012102183629A CN 201210218362 A CN201210218362 A CN 201210218362A CN 102707149 A CN102707149 A CN 102707149A
Authority
CN
China
Prior art keywords
voltage
uut
contact resistance
resistance
integration
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
Application number
CN2012102183629A
Other languages
Chinese (zh)
Other versions
CN102707149B (en
Inventor
任万滨
曹晟
周志凯
陈宇
武剑
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harbin Institute of Technology
Original Assignee
Harbin Institute of Technology
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Harbin Institute of Technology filed Critical Harbin Institute of Technology
Priority to CN201210218362.9A priority Critical patent/CN102707149B/en
Publication of CN102707149A publication Critical patent/CN102707149A/en
Application granted granted Critical
Publication of CN102707149B publication Critical patent/CN102707149B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Measurement Of Resistance Or Impedance (AREA)

Abstract

The invention discloses an integrating contact resistance measuring system and method, which relate to a resistance measuring system and method and are used for solving the problems of poor data stability and low accuracy existing in a contact resistance measuring method. The method comprises the following steps of: acquiring voltages across a component to be measured by adopting a high-resistance low-power voltage amplifier, and amplifying the acquired voltages; acquiring a voltage between the component to be measured and a standard current detection resistor by adopting a voltage follower, isolating to obtain a low-impedance output voltage, and inputting the low-impedance output voltage to a multipath AD (Analog to Digital) converter; setting the integral constant of an analog integrator by adopting a measuring range switching switch, and performing analog integration on the amplified voltage by adopting the analog integrator; computing voltages across a component to be measured and exciting current passing through the component to be measured by adopting a singlechip to obtain the resistance value of the component to be measured; and measuring integral contact resistance. The system and the method are suitable for measuring contact resistance.

Description

Integration type contact resistance measuring system and measuring method
Technical field
The present invention relates to a kind of resistance measurement system and measuring method.
Background technology
Measuring contact resistance belongs to microresistivity survey.The ultimate principle of such measuring system is a voltammetry, can be subdivided into DC-method, AC method and impulse method etc. again.
In the DC-method, right with the tested contact of known constant current excitation, through amplifying and measuring contact voltage is calculated tested resistance.In order to reach higher resolution, just must improve the enlargement factor that voltage is put amplifier, perhaps improve exciting current, brought problems such as noise increase, poor stability and energy consumption increase thus.
In the AC method, adopting alternating current to encourage tested contact right, and use passive device---transformer has reduced the amplification noise greatly as the voltage amplification element.But introduced new problem: the low-frequency transformer volume and weight is bigger, and the high frequency lower conductor can receive the influence of skin effect, makes the actual measurement resistance become big (relevant with test frequency).
In the impulse method, right with the current impulse excitation contact of certain peak value, can reduce energy consumption greatly, weak point is that this method paired pulses peak value ten minutes is responsive, and the difficult standard of surveying of peak value (especially narrow peak), so accuracy is difficult to improve.
Summary of the invention
The present invention is the problem poor for the data stability that solves the measuring contact resistance method, that accuracy is low, thereby a kind of integration type contact resistance measuring system and measuring method are provided.
The integration type contact resistance measuring system, it comprises controlled constant current source, standard inspection leakage resistance, high resistant low range voltage amplifier, analogue integrator, range shift switch, voltage follower, multi-channel A converter and single-chip microcomputer;
The power output end of controllable current source is connected with an end of UUT; The other end of said UUT is connected with an end of standard inspection leakage resistance; The other end of said standard inspection leakage resistance connects power supply ground;
High resistant low range voltage amplifier is gathered the voltage at UUT two ends; The voltage signal output end of said high resistant low range voltage amplifier is connected with the voltage signal input end of analogue integrator; The integration data output terminal of said analogue integrator is connected with one road input end of analog signal of multi-channel A converter; The adjustment signal input part of analogue integrator is connected with range shift switch;
Voltage between voltage follower collection standard inspection leakage resistance and the power supply ground; The voltage signal output end of said voltage follower is connected with one road input end of analog signal of multi-channel A converter;
The AD switching signal output terminal of multi-channel A converter is connected with the AD switching signal input end of single-chip microcomputer; The current controling signal output terminal of said single-chip microcomputer is connected with the current controling signal input end of controlled constant current source; The integrator control signal output ends of said single-chip microcomputer is connected with the reset signal input end of analogue integrator.
Based on the integration type measuring contact resistance method of said apparatus, it is realized by following steps:
Step 1, impose on UUT, adopt high resistant low range voltage amplifier to gather the terminal voltage at UUT two ends, and export to analogue integrator after the voltage signal of gathering amplified through Single-chip Controlling controllable current source output constant current signal;
Adopt the voltage between voltage follower collection standard inspection leakage resistance and the power supply ground to obtain the Low ESR output voltage U I, and with this voltage U IInput to the multi-channel A converter;
Step 2, employing range shift switch are set the integration constant of analogue integrator, adopt analogue integrator to carry out analog integration to amplifying back voltage in the step 1, and integral result is sent to the multi-channel A converter;
Step 3, employing single-chip microcomputer receive the Low ESR output voltage U in the multi-channel A converter IWith analog integration value U T, and according to formula:
U x = U T Aτ n T
Calculate the voltage U of UUT x
In the formula: τ nIt is the integration constant of analogue integrator; A is the gain multiple of high resistant low range voltage amplifier; T is integral time;
And according to formula:
I = U I R ref
Calculate exciting current I through UUT;
In the formula: R RefIt is the resistance of standard inspection leakage resistance;
The voltage U of step 4, UUT that step 3 is obtained xBe divided by with exciting current I through UUT, thus the resistance value of acquisition UUT; Thereby realize the measurement of integration type contact resistance.Adopt LCD MODULE that the resistance of the UUT of acquisition is shown.
Adopt keyboard that the exciting current I through UUT is set.
Single-chip microcomputer is implemented reset operation through an IO mouth to analogue integrator.
Analogue integrator output analog integration value U TAmplitude be 1/4 ~ 3/4 of multi-channel A converter reference voltage.
The data stability of measuring contact resistance method of the present invention is strong, accuracy is high.
Description of drawings
Fig. 1 is a structural representation of the present invention.
Embodiment
Embodiment one, combination Fig. 1 explain this embodiment; The integration type contact resistance measuring system, it comprises controlled constant current source 1, standard inspection leakage resistance 3, high resistant low range voltage amplifier 4, analogue integrator 5, range shift switch 6, voltage follower 7, multi-channel A converter 8 and single-chip microcomputer 9;
The power output end of controllable current source 1 is connected with an end of UUT 2; The other end of said UUT 2 is connected with an end of standard inspection leakage resistance 3; The other end of said standard inspection leakage resistance 3 connects power supply ground;
High resistant low range voltage amplifier 4 is gathered the voltage at UUT 2 two ends; The voltage signal output end of said high resistant low range voltage amplifier 4 is connected with the voltage signal input end of analogue integrator 5; The integration data output terminal of said analogue integrator 5 is connected with one road input end of analog signal of multi-channel A converter 8; The adjustment signal input part of analogue integrator 5 is connected with range shift switch 6;
Voltage between voltage follower 7 collection standards inspection leakage resistance 3 and the power supply ground; The voltage signal output end of said voltage follower 7 is connected with one road input end of analog signal of multi-channel A converter 8;
The AD switching signal output terminal of multi-channel A converter 8 is connected with the AD switching signal input end of single-chip microcomputer 9; The current controling signal output terminal of said single-chip microcomputer 9 is connected with the current controling signal input end of controlled constant current source 1; The integrator control signal output ends of said single-chip microcomputer 9 is connected with the reset signal input end of analogue integrator 5.
Effect of the present invention:
1, analogue integrator has the low characteristic of noise sensitivity, can provide than the better data stability of contact resistance measuring system in the past.
2, from the principle of at present existing contact resistance measuring system, tested contact is to voltage U xBe the most difficult accurate parameter of surveying, its reason is under different exciting currents, U xDynamic range too big, can reach from the 1nV magnitude until the 1V magnitude.Therefore forward voltage Amplifier Gain multiple needs to switch according to measurement range, brings the problem of offset voltage compensation difficulty thus, the inconsistent bad phenomenon of the measurement result of same resistance under different gears occurs.And this integration type contact resistance measuring system involved in the present invention; The enlargement ratio of its voltage amplifier is fixed and less (being no more than 100 times); Its benefit is that the compensation of offset voltage is simple; Overcome above-mentioned inconsistent problem fully, and be easy to the noise figure of step-down amplifier, the signal to noise ratio (S/N ratio) of measuring system guarantees easily.
3, through changing the integration constant switching range, only need a single pole multiple throw just can realize, simple in structure, be easy to safeguard.
4, measuring system is dynamically adjusted T integral time of analogue integrator 5 with software mode, makes the amplitude of analogue integrator output voltage U T be positioned at 1/4 ~ 3/4 scope of multi-channel A converter 8 reference voltages, can make full use of this section optimum linear scope.
The difference of embodiment two, this embodiment and embodiment one described integration type contact resistance measuring system is; It also comprises LCD MODULE 10, and the shows signal input end of said LCD MODULE 10 is connected with the shows signal output terminal of single-chip microcomputer 9.
The difference of embodiment three, this embodiment and embodiment one described integration type contact resistance measuring system is that it also comprises keyboard 11, and the keyboard signal output terminal of said keyboard 11 is connected with the keyboard signal input end of single-chip microcomputer 11.
The difference of embodiment four, this embodiment and embodiment one described integration type contact resistance measuring system is that the resistance of high resistant low range voltage amplifier 4 is greater than 1M Ω; The scope of multiplying power is: 1-100.
Embodiment five, based on the integration type measuring contact resistance method of embodiment one, it is realized by following steps:
Step 1, impose on UUT 2, adopt high resistant low range voltage amplifier 4 to gather the terminal voltage at UUTs 2 two ends, and export to analogue integrator 5 after the voltage signal of gathering amplified through single-chip microcomputer 9 control controllable current sources 1 output constant current signal;
Adopt the voltage between voltage follower 7 collection standards inspection leakage resistance 3 and the power supply ground to obtain the Low ESR output voltage U I, and with this voltage U IInput to multi-channel A converter 8;
Step 2, employing range shift switch 6 are set the integration constant of analogue integrators 5, amplify back voltage in 5 pairs of step 1 of employing analogue integrator and carry out analog integration, and integral result is sent to multi-channel A converter 8;
Step 3, the Low ESR output voltage U that adopts single-chip microcomputer 9 to receive in the multi-channel A converter 8 IWith analog integration value U T, and according to formula:
U x = U T A τ n T
Calculate the voltage U of UUT 2 x
In the formula: τ nIt is the integration constant of analogue integrator 5; A is the gain multiple of high resistant low range voltage amplifier 4; T is integral time;
And according to formula:
I = U I R ref
Calculate exciting current I through UUT 2;
In the formula: R RefIt is the resistance of standard inspection leakage resistance 3;
The voltage U of step 4, UUT 2 that step 3 is obtained xBe divided by with exciting current I through UUT 2, thus the resistance value of acquisition UUT 2; Thereby realize the measurement of integration type contact resistance.
Adopt the resistance of the UUT 2 of 10 pairs of acquisitions of LCD MODULE to show.
Adopt 11 couples of exciting current I of keyboard to set through UUT 2.
Single-chip microcomputer 9 is implemented reset operation through an IO mouth to analogue integrator 5.
Analogue integrator 5 output analog integration value U TAmplitude be 1/4 ~ 3/4 of multi-channel A converter 8 reference voltages.
The present invention is the core of whole integration type contact resistance measuring system with single-chip microcomputer 9; The DA converter output end is being controlled the output current (being exciting current I) of controlled constant current source 1 in its sheet, and has expanded AD converter 8, LCD MODULE 10 and keyboard 11 through the IO mouth.
The tested contact of the series relationship of the exciting current process of controlled constant current source 1 output is examined leakage resistance 3 (selecting accurate high-power wire-wound resistor for use) to 2 with standard.
Tested contact is to 2 voltage U xAfter amplifying by high resistant low range voltage amplifier 4, convert one and U into by analogue integrator 5 xThe magnitude of voltage U that is directly proportional T, the gain multiple A of its scale-up factor and high resistant low range voltage amplifier 4, the integration constant τ of analogue integrator 5 n(n=1,2,3,4 ...) and with integral time T relevant.
Be accurate measuring excitation electric current I, at first be converted into voltage signal, after high resistant voltage follower 7 is isolated, obtain output voltage U by standard inspection leakage resistance 3 I
The output voltage U of analogue integrator 5 TOutput voltage U with voltage follower 7 IGet into the CH0 passage and the CH1 passage of multi-channel A converter 8, and transfer digital quantity to, then under the control of single-chip microcomputer 9, get in the sheet, go out tested contact to 2 voltage U by software mode according to computes again xWith exciting current I:
U x = U T A τ n T - - - ( 1 )
I = U I R ref - - - ( 2 )
At this moment, according to the volt-ampere ratio juris, can calculate tested contact to resistance value R x:
R x=U x/I x (3)
Be about to R subsequently xOn LCD 10, show.
For being ready to the next circulation of measuring, single-chip microcomputer 8 is implemented reset operation through an IO mouth that is connected to analogue integrator 5 reset terminals (RESET end) to it, makes its internal integral electric capacity discharge output voltage U fully TFall after rise to zero fully.So far, complete measurement loop ends.
Single-chip microcomputer 9 extends out keyboard 11 and is used for exciting current I is set; The sheet internal program to integral time T dynamically adjust, thereby make the analogue integrator output voltage U TAmplitude be positioned at 1/4 ~ 3/4 scope of multi-channel A converter 8 reference voltages, make measuring system have better linearity.

Claims (8)

1. integration type contact resistance measuring system is characterized in that: it comprises controlled constant current source (1), standard inspection leakage resistance (3), high resistant low range voltage amplifier (4), analogue integrator (5), range shift switch (6), voltage follower (7), multi-channel A converter (8) and single-chip microcomputer (9);
The power output end of controllable current source (1) is connected with an end of UUT (2); The other end of said UUT (2) is connected with an end of standard inspection leakage resistance (3); The other end of said standard inspection leakage resistance (3) connects power supply ground;
High resistant low range voltage amplifier (4) is gathered the voltage at UUT (2) two ends; The voltage signal output end of said high resistant low range voltage amplifier (4) is connected with the voltage signal input end of analogue integrator (5); The integration data output terminal of said analogue integrator (5) is connected with one road input end of analog signal of multi-channel A converter (8); The adjustment signal input part of analogue integrator (5) is connected with range shift switch (6);
Voltage between voltage follower (7) collection standard inspection leakage resistance (3) and the power supply ground; The voltage signal output end of said voltage follower (7) is connected with one road input end of analog signal of multi-channel A converter (8);
The AD switching signal output terminal of multi-channel A converter (8) is connected with the AD switching signal input end of single-chip microcomputer (9); The current controling signal output terminal of said single-chip microcomputer (9) is connected with the current controling signal input end of controlled constant current source (1); The integrator control signal output ends of said single-chip microcomputer (9) is connected with the reset signal input end of analogue integrator (5).
2. integration type contact resistance measuring system according to claim 1 is characterized in that it also comprises LCD MODULE (10), and the shows signal input end of said LCD MODULE (10) is connected with the shows signal output terminal of single-chip microcomputer (9).
3. integration type contact resistance measuring system according to claim 1 is characterized in that it also comprises keyboard (11), and the keyboard signal output terminal of said keyboard (11) is connected with the keyboard signal input end of single-chip microcomputer (11).
4. integration type contact resistance measuring system according to claim 1, the resistance that it is characterized in that high resistant low range voltage amplifier (4) is greater than 1M Ω; The scope of multiplying power is: 1-100.
5. based on the integration type measuring contact resistance method of claim 1, it is characterized in that: it is realized by following steps:
Step 1, impose on UUT (2) through single-chip microcomputer (9) control controllable current source (1) output constant current signal; Adopt high resistant low range voltage amplifier (4) to gather the terminal voltage at UUT (2) two ends, and with exporting to analogue integrator (5) after the voltage signal amplification of gathering;
Adopt the voltage between voltage follower (7) collection standard inspection leakage resistance (3) and the power supply ground to obtain the Low ESR output voltage U I, and with this voltage U IInput to multi-channel A converter (8);
Step 2, employing range shift switch (6) are set the integration constant of analogue integrator (5), adopt analogue integrator (5) to carry out analog integration to amplifying back voltage in the step 1, and integral result is sent to multi-channel A converter (8);
Step 3, employing single-chip microcomputer (9) receive the Low ESR output voltage U in the multi-channel A converter (8) IWith analog integration value U T, and according to formula:
U x = U T A τ n T
Calculate the voltage U of UUT (2) x
In the formula: τ nIt is the integration constant of analogue integrator (5); A is the gain multiple of high resistant low range voltage amplifier (4); T is integral time;
And according to formula:
I = U I R ref
Calculate exciting current I through UUT (2);
In the formula: R RefIt is the resistance of standard inspection leakage resistance (3);
The voltage U of step 4, UUT (2) that step 3 is obtained xBe divided by with exciting current I through UUT (2), thus the resistance value of acquisition UUT (2); Thereby realize the measurement of integration type contact resistance.
5, integration type measuring contact resistance method according to claim 4 is characterized in that adopting LCD MODULE (10) that the resistance of the UUT (2) of acquisition is shown.
6. integration type measuring contact resistance method according to claim 4 is characterized in that adopting keyboard (11) that the exciting current I through UUT (2) is set.
7. integration type measuring contact resistance method according to claim 4 is characterized in that single-chip microcomputer (9) passes through an IO mouth analogue integrator (5) is implemented reset operation.
8. integration type measuring contact resistance method according to claim 4 is characterized in that analogue integrator (5) output analog integration value U TAmplitude be 1/4 ~ 3/4 of multi-channel A converter (8) reference voltage.
CN201210218362.9A 2012-06-28 2012-06-28 Integrating contact resistance measuring system and method Expired - Fee Related CN102707149B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201210218362.9A CN102707149B (en) 2012-06-28 2012-06-28 Integrating contact resistance measuring system and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201210218362.9A CN102707149B (en) 2012-06-28 2012-06-28 Integrating contact resistance measuring system and method

Publications (2)

Publication Number Publication Date
CN102707149A true CN102707149A (en) 2012-10-03
CN102707149B CN102707149B (en) 2015-03-04

Family

ID=46900082

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201210218362.9A Expired - Fee Related CN102707149B (en) 2012-06-28 2012-06-28 Integrating contact resistance measuring system and method

Country Status (1)

Country Link
CN (1) CN102707149B (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103149442A (en) * 2013-02-08 2013-06-12 哈尔滨工业大学 Automatic testing device for contact resistor made of electrical contact material
CN105717363A (en) * 2016-04-06 2016-06-29 威胜集团有限公司 Current loop impedance testing device of smart meter and impedance calculation method
CN105866545A (en) * 2016-05-18 2016-08-17 武汉精测电子技术股份有限公司 ITO (indium tin oxide) line impedance measurement device and method and analog signal generator
CN109307839A (en) * 2018-11-23 2019-02-05 哈尔滨工业大学 The circuit of contact drop is tested during ac electric apparatus electrical endurance
CN111693779A (en) * 2020-06-19 2020-09-22 珠海市运泰利自动化设备有限公司 High-precision measuring system for ultrahigh impedance of low-voltage device
CN116381347A (en) * 2022-12-05 2023-07-04 哈尔滨理工大学 Method for acquiring alternating-current equivalent resistance of large-section cable conductor based on peak characteristic

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60201266A (en) * 1984-03-27 1985-10-11 Kyowa Dengiyou:Kk Digital resistance meter
CN86103182A (en) * 1985-06-25 1986-12-24 海德罗-魁北克公司 Measure very low-resistance method and ohmmeter
JPS62174664A (en) * 1986-01-28 1987-07-31 Hioki Denki Kk Resistance measuring circuit
CN101236220A (en) * 2008-03-07 2008-08-06 北京邮电大学 System and method for testing jiggle contact resistance

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60201266A (en) * 1984-03-27 1985-10-11 Kyowa Dengiyou:Kk Digital resistance meter
CN86103182A (en) * 1985-06-25 1986-12-24 海德罗-魁北克公司 Measure very low-resistance method and ohmmeter
JPS62174664A (en) * 1986-01-28 1987-07-31 Hioki Denki Kk Resistance measuring circuit
CN101236220A (en) * 2008-03-07 2008-08-06 北京邮电大学 System and method for testing jiggle contact resistance

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
吴文全等: "μΩ级小电阻测量方法研究", 《电测与仪表》 *
朱琴跃等: "基于单片机控制的接触电阻自动检测仪的研究", 《交通与计算机》 *
石颉等: "一种跟踪接触电阻变化趋势的测量装置", 《微型机与应用》 *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103149442A (en) * 2013-02-08 2013-06-12 哈尔滨工业大学 Automatic testing device for contact resistor made of electrical contact material
CN103149442B (en) * 2013-02-08 2015-04-29 哈尔滨工业大学 Automatic testing device for contact resistor made of electrical contact material
CN105717363A (en) * 2016-04-06 2016-06-29 威胜集团有限公司 Current loop impedance testing device of smart meter and impedance calculation method
CN105866545A (en) * 2016-05-18 2016-08-17 武汉精测电子技术股份有限公司 ITO (indium tin oxide) line impedance measurement device and method and analog signal generator
CN109307839A (en) * 2018-11-23 2019-02-05 哈尔滨工业大学 The circuit of contact drop is tested during ac electric apparatus electrical endurance
CN109307839B (en) * 2018-11-23 2020-08-11 哈尔滨工业大学 Circuit for testing contact voltage drop in alternating current electrical appliance electrical life experimental process
CN111693779A (en) * 2020-06-19 2020-09-22 珠海市运泰利自动化设备有限公司 High-precision measuring system for ultrahigh impedance of low-voltage device
CN116381347A (en) * 2022-12-05 2023-07-04 哈尔滨理工大学 Method for acquiring alternating-current equivalent resistance of large-section cable conductor based on peak characteristic
CN116381347B (en) * 2022-12-05 2023-10-24 哈尔滨理工大学 Method for acquiring alternating-current equivalent resistance of large-section cable conductor based on peak characteristic

Also Published As

Publication number Publication date
CN102707149B (en) 2015-03-04

Similar Documents

Publication Publication Date Title
CN101865986B (en) System and method for checking error of high-voltage electric energy measurement device
CN102707149B (en) Integrating contact resistance measuring system and method
CN102841260A (en) DC microresistivity measuring system
CN101295188B (en) DC small current constant-current source and calibration method thereof
CN201425621Y (en) Error checking system of high-voltage electric energy metering device
CN101315362B (en) Fabric specific resistance instrument, fabric resistor and fabric specific resistance measurement method
CN105334487A (en) Direct-current watt-hour meter calibrating device
CN205157761U (en) Detection device for direct current electric energy meter
CN102323474A (en) Digital readout ampere meter for detecting pulse current
CN102707153A (en) Contact resistance measuring system and method based on voltage-frequency conversion method
CN204347229U (en) The calibrating installation of active leakage current tester
CN104535954B (en) Calibration device and method of active leakage current tester
CN207366731U (en) A kind of intelligent electric energy meter detection device
CN114200381B (en) Intelligent ammeter reliability detection system and method
CN105372614A (en) Electronic type automatic zero-setting method and device
CN112557732B (en) Magnitude tracing method and system of impulse current measuring device based on induction coil
CN104267262B (en) A kind of high-precision loop resistance intelligent tester
JPH0394178A (en) Measuring device for high frequency signal
CN113866661A (en) Power supply dynamic response test method, system and related components
CN103000361A (en) Current transformer
CN1022203C (en) Electric quantity transducer and check meter of watt-hour meter
CN116991197A (en) Accurate simulation device and method for weak electrophysiological signals
CN215494086U (en) Error calibration device of differential voltage transformer
CN204988943U (en) High accuracy metal material fatigue damage test instrument
CN210005595U (en) thermal resistance four-wire system real-time measuring circuit

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20150304

Termination date: 20150628

EXPY Termination of patent right or utility model