CN2104452U - Instrument for measuring low resistance and large current - Google Patents
Instrument for measuring low resistance and large current Download PDFInfo
- Publication number
- CN2104452U CN2104452U CN 91223236 CN91223236U CN2104452U CN 2104452 U CN2104452 U CN 2104452U CN 91223236 CN91223236 CN 91223236 CN 91223236 U CN91223236 U CN 91223236U CN 2104452 U CN2104452 U CN 2104452U
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- low resistance
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- 239000004020 conductor Substances 0.000 claims abstract description 28
- 230000003321 amplification Effects 0.000 claims abstract description 11
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 11
- 238000005259 measurement Methods 0.000 claims description 29
- 230000002401 inhibitory effect Effects 0.000 abstract 1
- 238000003466 welding Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
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Abstract
The utility model relates to a low resistance and heavy current measuring apparatus, which is composed of a constant-current source, a measuring control circuit, an operational amplification circuit, an interface circuit, a four-digit display unit and a housing body. The utility model is an instrument used for measuring the direct current resistance value of a conductive body to be measured, and the conductor can be allowed to pass through the electric current with more than 1 ampere, and the resistance value is from 20 micro ohm to 20 ohm. The utility model has strong inhibiting capacity on the interference of misconnection, an alternate current magnetic field, a distributed capacitance, a distributed inductance, etc. The utility model can stably and quickly measure current, and can truly reflect the direct current resistance value of the conductive body to be measured. The utility model is suitable for measuring medium and small-sized switches and contact points of a relay, and is suitable for measuring the existence of the misconnection or the resistance value in various welded interfaces.
Description
Low resistance Super-Current Measurement instrument of the present utility model be used to measure allow by electric current more than 1 ampere, resistance value is at the instrument of the dc resistance of the measured conductor of 20 micro-ohms to 20 ohm.As measure the contact point of middle-size and small-size switch and relay, various welding junctions etc., be particularly useful for measuring the direct current resistance of inductive load, as big-and-middle-sized transformer, generator and motor etc.
During usually with the dc resistance of the above-mentioned measured conductor of apparatus measures such as electric bridge or micro-ohm table, measured conductor is passed to a milliampere level electric current.Because electric current is too small, make the input signal of asking for very weak, be easy to be subjected to the interference of factors such as virtual connection, AC magnetic field, distributed capacitance and distributed inductance, and make measuring current instability or the stabilization time of flowing through measured conductor long, influence measurement result even, can not truly reflect the dc resistance of measured conductor.
The task of low resistance Super-Current Measurement instrument of the present utility model is, when measuring the measured conductor of dc resistance in 20 micro-ohms to 20 ohm, raising is to the antijamming capability of factors such as virtual connection, AC magnetic field, distributed capacitance and distributed inductance, make measuring current very fast stable, truly reflect the dc resistance of measured conductor.
Theoretical analysis and practice show, measure whether virtual connection such as middle-size and small-size switch and the contact point of relay, various welding junctions etc., as passing to milliampere little electric current of level, and be to be difficult to accurately judge whether virtual connection.But as pass to big electric current more than 1 ampere, then the contact of virtual connection place is blown because of overheated, so can judge the whether virtual connection of this contact at once.
To the conductor that disturbed by factors such as AC magnetic field, distributed capacitance and distributed inductance, pass to the big electric current more than 1 ampere, the input signal of asking for is strengthened, shortened duration of charging to distributed capacitance and distributed inductance, thereby make measuring current very fast stable, reflect the dc resistance of measured conductor truly.
How accompanying drawings task of the present utility model realizes.
Fig. 1 is the front projection figure of low resistance Super-Current Measurement instrument of the present utility model.
Fig. 2 is the side projection figure of low resistance Super-Current Measurement instrument of the present utility model.
Fig. 3 is the electrical principle block diagram of low resistance Super-Current Measurement instrument of the present utility model.
Fig. 4 is the electrical schematic diagram of operational amplification circuit.
Fig. 1 to Fig. 4 is one of embodiment of the present utility model.
Low resistance Super-Current Measurement instrument of the present utility model mainly shows device by constant current source, circuit of measurement and control, operational amplification circuit, interface circuit, 4 1/2 figure places and housing is formed.
Constant current source is made up of sample circuit, major loop and high-low voltage power source.Sample circuit mainly is made up of resistance.Major loop mainly is made up of operational amplifier, large power triode and measured conductor.High-low voltage power source mainly is made up of the power supply module of adjustable voltage and triode etc.
Circuit of measurement and control mainly is made up of fourth gear button and relay.
Operational amplification circuit mainly is made up of the operational amplifier and the resistance of five low drifts.
Low resistance Super-Current Measurement instrument of the present utility model is feeding the constant big electric current more than 1 ampere on the measured conductor.
Measured conductor is serially connected in the constant current source.Sample circuit is asked for signal and is fed back to the input end that hangs down the operational amplifier that drifts about from the major loop of constant current source.Operational amplifier compares feedback signal on the sample circuit and reference voltage, in time adjusts the electric current on the major loop automatically, and is constant thereby the current constant of measured conductor is flow through in assurance.Because the resistance change scope of measured conductor is bigger,, supplies with constant current source by rectification high pressure and low pressure two-way power supply and select to use in order to guarantee constant current source good operation point.
Big electric current by constant current source provides flows through measured conductor, and produces voltage drop, i.e. input signal at the measured conductor two ends.The size of this input signal is directly proportional with the resistance value of measured conductor.Input signal enters circuit of measurement and control by contact P1, P2.
The branch multiplying power of the fourth gear button of circuit of measurement and control is respectively * 1, * 0.1, * 0.01 and * 0.001.Measure the highest resistance scope and be respectively 19999 milliohms, 1999.9 milliohms, 199.99 milliohms and 19.999 milliohms.When exceeding every grade of maximum resistance scope, digital display device shows " 0000 " and flicker automatically.Every grade of input signal enters operational amplification circuit respectively.
Acting as of the operational amplifier of five low drifts of operational amplification circuit: operational amplifier 1 suppresses the direct current common-mode signal and participates in computing with operational amplifier 3 to amplify, operational amplifier 2 suppresses to exchange common-mode signal, and operational amplifier 4 and 5 is an emitter follower.The resistance value that changes the resistance on the button then obtains different enlargement factors, and this amplifying circuit then obtains four kinds of enlargement factors with compositions such as circuit of measurement and control, is 1/10,1,10 and 100 times.
Input signal through operational amplification circuit passes through interface circuit, enters into 4 1/2 figure places and shows device, and demonstrate the real dc resistance of measured conductor.
Zeroing knob and " releasing " button are arranged on the case panel of low resistance Super-Current Measurement instrument of the present utility model.
Because low resistance Super-Current Measurement instrument of the present utility model has zeroing knob and corresponding operational amplification circuit, so at normal temperatures, can guarantee that measuring accuracy is in 0.2% scope.
Circuit of measurement and control and operational amplification circuit, 4 1/2 figure places show device makes the resistance value of reading value and measured conductor set up corresponding relation.Its corresponding relation is:
The branch multiplying power of the resistance value of measured conductor=demonstration reading value * measurement shelves.The unit of resistance value is a milliohm.
At operation low resistance Super-Current Measurement instrument of the present utility model, when when not considering the resistance of external lead wire, at first press " disengage button ", the outermost two ends of measured conductor are connected on C1, the C2 binding post with thick lead-in wire, and the two ends in addition of measured conductor are connected on P1, the P2 binding post with general lead-in wire.Select suitable class, with " zeroing knob " school zero.And then make it to lift by " disengage button ", 4 1/2 figure places show the device numeral and show and get final product reading after stable after 5～20 seconds.Numeral runs through, and by " disengage button ", makes this button closure again, makes the measured conductor discharge automatically.
At operation low resistance Super-Current Measurement instrument of the present utility model, in the time will considering the resistance of external lead wire, as long as the terminal short circuit that makes four lead-in wires is together, repeat the resistance that above-mentioned steps can be measured lead-in wire, also just extrapolate the resistance of measured conductor.
The contact point of centering switchette and relay and various welding junction, detect its whether virtual connection with low resistance Super-Current Measurement instrument of the present utility model, because the big electric current by 1 ampere makes the contact of virtual connection place be blown because of overheated, resistance becomes greatly suddenly, and then judging this point is virtual connection.
To such as inductive loads such as big-and-middle-sized transformer, generator and motor, when measuring its dc resistance, be vulnerable to most the interference of factors such as AC magnetic field, distributed capacitance and distributed inductance, use low resistance Super-Current Measurement instrument of the present utility model, pass to 1 ampere big electric current, the input signal of asking for is strengthened, improved antijamming capability above-mentioned disturbing factor, make measuring current very fast stable, reflect the dc resistance of measured conductor truly.
Obviously, low resistance Super-Current Measurement instrument of the present utility model has been finished the task of regulation of the present utility model.
Claims (4)
1, a kind of low resistance Super-Current Measurement instrument of forming by interface circuit, the apparent device of 4 1/2 figure places and housing etc., it is characterized in that being made up of constant current source, circuit of measurement and control and operational amplification circuit, described low resistance Super-Current Measurement instrument is feeding the constant big electric current more than 1 ampere on the measured conductor.
2, according to the described low resistance Super-Current Measurement of claim 1 instrument, it is characterized in that constant current source is made up of sample circuit, major loop and high-low voltage power source, the sample circuit of constant current source mainly is made up of resistance, the major loop of constant current source mainly is made up of operational amplifier, large power triode and measured conductor, and the high-low voltage power source of constant current source mainly is made up of the power supply module and the triode of adjustable voltage.
3,, it is characterized in that circuit of measurement and control mainly is made up of fourth gear button and relay according to the described low resistance Super-Current Measurement of claim 1 instrument.
4,, it is characterized in that operational amplification circuit mainly is made up of the operational amplifier and the resistance of five low drifts according to the described low resistance Super-Current Measurement of claim 1 instrument.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91223236 CN2104452U (en) | 1991-08-19 | 1991-08-19 | Instrument for measuring low resistance and large current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91223236 CN2104452U (en) | 1991-08-19 | 1991-08-19 | Instrument for measuring low resistance and large current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2104452U true CN2104452U (en) | 1992-05-13 |
Family
ID=50441137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 91223236 Pending CN2104452U (en) | 1991-08-19 | 1991-08-19 | Instrument for measuring low resistance and large current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2104452U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101718812B (en) * | 2009-12-11 | 2011-07-27 | 力柏时代锂动力科技（北京）有限公司 | DC current measurement circuit |
| CN102955070A (en) * | 2011-08-17 | 2013-03-06 | 鸿富锦精密工业（深圳）有限公司 | Resistance measuring circuit |
| CN105823927A (en) * | 2016-03-16 | 2016-08-03 | 昆山软龙格自动化技术有限公司 | Resistance measuring method for low-resistance object integrated in test card |
| US10209286B2 (en) | 2016-02-15 | 2019-02-19 | Ford Global Technologies, Llc | Resistance measurement tool |
| CN110108945A (en) * | 2019-05-20 | 2019-08-09 | 深圳市新威尔电子有限公司 | Two-wire system resistance measurement method |
-
1991
- 1991-08-19 CN CN 91223236 patent/CN2104452U/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101718812B (en) * | 2009-12-11 | 2011-07-27 | 力柏时代锂动力科技（北京）有限公司 | DC current measurement circuit |
| CN102955070A (en) * | 2011-08-17 | 2013-03-06 | 鸿富锦精密工业（深圳）有限公司 | Resistance measuring circuit |
| US10209286B2 (en) | 2016-02-15 | 2019-02-19 | Ford Global Technologies, Llc | Resistance measurement tool |
| CN105823927A (en) * | 2016-03-16 | 2016-08-03 | 昆山软龙格自动化技术有限公司 | Resistance measuring method for low-resistance object integrated in test card |
| CN105823927B (en) * | 2016-03-16 | 2018-11-20 | 昆山软龙格自动化技术有限公司 | A kind of resistance value measurement method for the small resistance value object being integrated in test card |
| CN110108945A (en) * | 2019-05-20 | 2019-08-09 | 深圳市新威尔电子有限公司 | Two-wire system resistance measurement method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| AD01 | Patent right deemed abandoned | ||
| C20 | Patent right or utility model deemed to be abandoned or is abandoned |