CN201166682Y - Test circuit special for multimeter adaptive voltage cascade low-resistance - Google Patents
Test circuit special for multimeter adaptive voltage cascade low-resistance Download PDFInfo
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- CN201166682Y CN201166682Y CNU2008201012434U CN200820101243U CN201166682Y CN 201166682 Y CN201166682 Y CN 201166682Y CN U2008201012434 U CNU2008201012434 U CN U2008201012434U CN 200820101243 U CN200820101243 U CN 200820101243U CN 201166682 Y CN201166682 Y CN 201166682Y
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- low
- multimeter
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- test circuit
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- 238000012360 testing method Methods 0.000 title claims abstract description 38
- 230000003044 adaptive effect Effects 0.000 title description 8
- 238000000034 method Methods 0.000 abstract description 12
- 238000010586 diagram Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
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- 230000015572 biosynthetic process Effects 0.000 description 1
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Abstract
The utility model discloses a special test circuit used for testing proper voltage and low series connection resistance of a multimeter. The special test circuit adopts the technical proposal that a low-value standard resistance is connected with a tested resistance in series, so as to form a circuit, then the circuit is connected with a low voltage power supply and the adjustable resistance of a fixed resistor in series, and a low tension battery is adjusted to serve as a power supply, thereby composing a special test circuit used for testing the proper voltage and the low series connection resistance; the special test circuit is separated from the original switching circuit and the shared circuit of the multimeter, thereby enabling the tested voltage to be proper at the potential terminal of the resistance, and realizing the resistance test by adopting the four-terminal method. The special test circuit suits a pointer multimeter, an electronic multimeter and a digital multimeter, and also suits a milivoltmeter (also including an AV milivoltmeter), the input resistance value of which is larger than the low-value standard resistance orders of magnitude, that is, the tested shunt does not influence the testing accuracy. The special test circuit is especially applicable to a digital dual-display multimeter and a dual-channel AV milivoltmeter, and even uses an oscilloscope as a display, thereby having wide application scope, simple circuit, low cost, easy operation and convenient popularization.
Description
Technical field
The utility model belongs to the electrotechnical, electronic instrument, particularly multimeter test low resistance
Background technology
Present multimeter, particularly portable, all can not survey low resistance, i.e. the magnitude of the following m Ω of 1 Ω, it is R * 1 range that pointer gauge adopts adaptive electric current series process measuring resistance minimum, the center resistance is 10 Ω, and 1 Ω scale segments most has only 0.2 Ω, as with R * 0.1 range, used 1.5V battery, power consumption 1.5A can not realize in practicality, thereby still consumes bigger electric current when adopting the so-called table of falling Ω of adaptive current parallel method such as 500-I type owing to measuring resistance not and be eliminated.And adaptive electric current becomes 0 to ∞ the special-purpose scale that all needs reciprocal with resistance.Digital watch adopts the minimum 2k of the having only Ω of constant flow method range in early days, all uses rule of three now instead, and minimum range is 200 Ω.Be subjected to the little restriction of 9V battery current capacity on the one hand, be subjected to the influence of changeover contact, wiring, test pencil constant resistance in addition, looking 2 Ω ranges survey low resistance is the forbidden zone.20 Ω ranges once appearred the nineties, because of above-mentioned reason error greatly also stops production.There are many patents to reach 20 Ω ranges again with resistance meter employing amount ZL86207705, used is two hold-carrying test circuits, make measuring resistance deduct the resistance of above-mentioned wiring etc., make test more accurate, but still because the resistance instability of contact etc., accuracy is affected, portable timepiece has adopted the 1.5V battery in the recent period, desk-top table adopts the power supply that exchanges economize on electricity, may solve and on the low value measuring resistance, produce the big adaptive general reference voltage 100mv of electric current, also can constitute the special-purpose four-end method test circuit of low-resistance test, even possessed the feasibility of test low-resistance, still be minimum range with 200 Ω,, have the low-resistance test function and wasted multimeter so also use the double bridge or the expensive special digital milliohmmeter of complicated operation.Existing pointer multimeter should be defined as adaptive current method with series process and multiple process.Because the relation that electric current and resistance are inversely proportional to, its scale is heterogeneous, needs the special-purpose scale of Ω.And digital multimeter generally can only be by the even reading of numeral, and what have has adopted adaptive electric current series process in order to survey high resistant, superelevation resistance, can only the read current value, can only survey G with current gear
XElectricity is led, and needs to convert, and illustrates that with this adaptive current method adopts the digital reading that not only consumes the neutral gear electric current but also be not suitable for use in digital watch in parallel.
Summary of the invention
The purpose of this utility model is: the utility model is at the deficiencies in the prior art, and the low resistance test circuit of a kind of multimeter with the adapt voltages series connection is provided.
The utility model adopts the low value measuring resistance to connect with measured resistance, be connected in series low-tension supply again, be serially connected with the adjustable resistance of fixed resistance, turn down the piezoelectricity pond and make power supply, constitute adapt voltages series connection low-resistance test special circuit, separate with the original change-over circuit and the common circuit of multimeter, make the voltage of test can fit in the potential end of resistance, realize the four-end method test of low-resistance; Thereby can by adjustable resistance make on measuring resistance produce adapt to millivolt full scale with and the fixed value voltage of fractional value, but promptly determined the voltage adaptation of measured resistance to become the ohmic value of direct-reading.
The potential end of low value measuring resistance described in the utility model and measured resistance connects reference voltage terminal, test input respectively.
Low-tension supply described in the utility model is the 1.5V battery, and low value measuring resistance resistance is 1 Ω, and the employing resistance in the adjustable resistance is the adjustable potentiometer of low resistance 5-10 Ω.
The utility model another program is connected with measured resistance by measuring resistance, is connected in series low-tension supply and resistance translation circuit again and constitutes.The resistance translation circuit is made of single tube transistor or Darlington, the adjustable resistance that is serially connected with fixed resistance, and adjustable resistance is the transistor base biasing resistor.
Low-tension supply described in the utility model is the 1.5V battery or makes normal power with 1.5V that 9V or 15V make accessory power supply.
Low value measuring resistance resistance described in the utility model is 1 Ω, and the employing resistance in the adjustable resistance is the adjustable potentiometer of low resistance 5-10 Ω.
The utility model is fit to pointer-type, electronic type, digimer, also is fit to input and hinders the milivoltmeter that the shunting of promptly measuring greater than a low value measuring resistance order of magnitude does not influence test accuracy, also comprises ac millivoltmeter.Be specially adapted to two demonstration multimeters of numeral and binary channels ac millivoltmeter, even do display with oscillograph, it is wide to be suitable for the instrument scope, and circuit is simple, and cost is low, and is simple to operate, is convenient to popularization and application.
Description of drawings
Fig. 1 is the utility model embodiment 1 circuit theory diagrams;
Fig. 2 is the utility model embodiment 2 circuit theory diagrams;
Fig. 3 is the utility model embodiment 3 circuit theory diagrams;
Fig. 4 is the utility model embodiment 4 circuit theory diagrams.
Embodiment
Below in conjunction with accompanying drawing the utility model is elaborated.
Embodiment 1
Referring to accompanying drawing 1, present embodiment comprises low value measuring resistance R
S, low-tension supply E, be serially connected with the adjustable resistance R of fixed resistance
A, mV table and insurance F
SAdopt measuring resistance R
SWith measured resistance R
XSeries connection is connected in series low-tension supply E again, is serially connected with the adjustable resistance R of fixed resistance
AMeasuring resistance R
SWith measured resistance R
XBetween serial connection insurance F
SLow-tension supply E adopts the 1.5V direct supply.Transfer adjustable resistance R during use
AMake measuring resistance R
SAdapt to the V of mV table full scale and fractional value thereof
SVoltage is surveyed R
XOn voltage V
XBut, direct-reading R
XValue.If R
SBe 1 Ω, pointer header circuit full scale voltage 100mV transfers adjustable resistance R
AMake V
SFit in full scale value, V
XCan be by full scale direct-reading R
XValue; Digital table adjustment V
SAt 100mV, V
XValue 1mV is 10m Ω; With rule of three and 1.5V battery, R
ACan be fixed as 10 Ω, V
SCan fit in and meet reference voltage terminal V about 100mV
BEF, V
XMeet test input V
INGet final product.
This circuit separates with original range conversion of multimeter and circuit, tests low-resistance special circuit to realize four-end method, makes R
SOn V
SAnd R
XOn voltage V
XCan fit in potential end, the influence of having avoided contact lead, an examination resistance to produce voltage by electric current.
Wherein low-tension supply E adopts the 1.5V battery or constitutes and resistance R according to the existing power supply of multimeter
A, R
S, R
XSeries circuit.Resistance R
AAdopt the potentiometer of low resistance 5-10 Ω to add fixedly resistor group one-tenth, the potentiometer of available metal piece type and conductive plastics type also can be connected in series fuse F
sB is a basic circuit among the figure, shows conversion testing with mV, and A is for to test with rule of three.
Because R
XAt series circuit, during measuring resistance, the loop does not disconnect, not current sinking.
This circuit not only is fit to pointer-type, electronic type, and digimer also is fit to input and hinders the milivoltmeter that the shunting of promptly measuring greater than a low value measuring resistance order of magnitude does not influence accuracy of test, also comprises ac millivoltmeter.Be specially adapted to two demonstration multimeters of numeral and binary channels ac millivoltmeter.
Embodiment 2
Referring to Fig. 2, present embodiment is by measuring resistance R
S, fuse F
SWith measured resistance R
XSeries connection is connected in series the resistance translation circuit again and constitutes, the resistance translation circuit by power supply E, be serially connected with the adjustable resistance R of fixed resistance
AAnd the single tube transistor T constitutes.Be serially connected with the adjustable resistance R of fixed resistance
ABe the base biasing resistor of single tube transistor T, single tube transistor T emitter connects power supply E, measuring resistance R
SFuse F
SWith measured resistance R
XSeries arm.
Adjustable resistance R
ABe carbon film potentioneter, can regulate continuously, can regulate the transistor base electric current and make the collection emitter-base bandgap grading amplified current resistive that electrifies change effect.
Embodiment 3
Referring to Fig. 3, present embodiment measuring resistance R
S, fuse F
SWith measured resistance R
XSeries connection is connected in series the resistance translation circuit again and constitutes, the resistance translation circuit by power supply E, be serially connected with the adjustable resistance R of fixed resistance
AReach Darlington T, be serially connected with the adjustable resistance R of fixed resistance
ABe the base biasing resistor of Darlington T, power supply E goes here and there in Darlington T and measuring resistance R
S, fuse F
SWith measured resistance R
XOn the series arm, it comprises the first power supply E and the second source E that is in series, and the common port of two power supplys links to each other with Darlington T collector.
The resistance translation circuit can reduce base current except playing the resistance conversion effect, help reducing the current sinking of accessory power supply such as 9V laminated cell.Pointer table is highly sensitive all adorns two kinds of batteries, and 1.5V can make normal power, and 9V or 15V can make accessory power supply.Normal power is to produce the electric current of adapt voltages about 100mV greatly about 100mA on the measuring resistance of basic circuit.It is very big because of enlargement factor that 9V, 15V supply with base supply, and electric current is little of 10 μ A.
Embodiment 4
Present embodiment measuring resistance R
S, fuse F
SWith measured resistance R
XSeries connection is connected in series the resistance translation circuit again and constitutes, and the resistance translation circuit is by power supply E, accessory power supply E
FBe serially connected with the adjustable resistance R of fixed resistance
AReach Darlington T, be serially connected with the adjustable resistance R of fixed resistance
ABe the base biasing resistor of Darlington T, power supply E goes here and there in Darlington T and measuring resistance R
S, fuse F
SWith measured resistance R
XOn the series arm, it comprises the first power supply E and the second source E that is in series, cross-over connection voltage stabilizing diode CW between the common port of two power supplys and Darlington T base stage, and the common port of two power supplys and Darlington T emitter span are connected to resistance R e.
At pointer multimeter, no matter general highly sensitive gauge outfit circuit uses gauge outfit circuit or mV range in the standard value of 100mV, all can be at R
SOn voltage adjustment be fitted on full scale value 1/2,1/2.5, etc.As R
SBe 1 Ω, corresponding R
XBe 1 Ω or 2 Ω, 2.5 Ω etc., be fit to 1,2,2.5 full scale values of reading.
The utility model also is applicable to the direct current milivoltmeter of internal resistance greater than low value measuring resistance several magnitude applicable to pointer multimeter and digimer.Seniority numeral multimeter can replace DC potentiometer fully now, the particularly the most accurate current comparator formula potential difference meter and the electric bridge of formation thereof, and the impedance instrument of intelligent digital table replaced surveying the alternating current bridge of component parameters, makes the electric bridge of complicated operation to become history.
Claims (6)
1, a kind of multimeter adapt voltages series connection low-resistance dedicated test circuit is characterized in that: by low value measuring resistance (R
S) and measured resistance (R
X) series connection, being connected in series low-tension supply (E) and resistance translation circuit again and constituting, the resistance translation circuit is the adjustable resistance (R that is serially connected with fixed resistance
A).
2, multimeter adapt voltages series connection low-resistance dedicated test circuit according to claim 1 is characterized in that: low value measuring resistance (R
S) and measured resistance (R
X) potential end (V
S, V
X) meet reference voltage terminal (V respectively
BEF), test input (V
IN).
3, multimeter adapt voltages series connection low-resistance dedicated test circuit according to claim 1, it is characterized in that: low-tension supply (E) is 1.5V battery, low value measuring resistance (R
S) resistance is 1 Ω, adjustable resistance (R
A) in the employing resistance be the adjustable potentiometer of low resistance 5-10 Ω.
4, a kind of multimeter adapt voltages series connection low-resistance dedicated test circuit is characterized in that: by measuring resistance (R
S) and measured resistance (R
X) series connection, be connected in series low-tension supply (E) and resistance translation circuit again and constitute, the resistance translation circuit by single tube transistor or Darlington, be serially connected with the adjustable resistance (R of fixed resistance
A) constitute adjustable resistance (R
A) be the transistor base biasing resistor.
5, multimeter adapt voltages series connection low-resistance dedicated test circuit according to claim 4, it is characterized in that: low-tension supply (E) is made normal power for the 1.5V battery or with 1.5V, and 9V or 15V make accessory power supply.
6, according to claim 4 or 5 described multimeter adapt voltages series connection low-resistance dedicated test circuits, it is characterized in that: low value measuring resistance (R
S) resistance is 1 Ω, adjustable resistance (R
A) in the employing resistance be the adjustable potentiometer of low resistance 5-10 Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201012434U CN201166682Y (en) | 2008-01-18 | 2008-01-18 | Test circuit special for multimeter adaptive voltage cascade low-resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201012434U CN201166682Y (en) | 2008-01-18 | 2008-01-18 | Test circuit special for multimeter adaptive voltage cascade low-resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201166682Y true CN201166682Y (en) | 2008-12-17 |
Family
ID=40192072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201012434U Expired - Fee Related CN201166682Y (en) | 2008-01-18 | 2008-01-18 | Test circuit special for multimeter adaptive voltage cascade low-resistance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201166682Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102955070A (en) * | 2011-08-17 | 2013-03-06 | 鸿富锦精密工业（深圳）有限公司 | Resistance measuring circuit |
| CN103439579A (en) * | 2013-08-30 | 2013-12-11 | 昆山奥德鲁自动化技术有限公司 | Economical impedance measurement circuit |
| CN106249049A (en) * | 2016-08-25 | 2016-12-21 | 华东光电集成器件研究所 | A kind of device improving extreme value thick-film resistor laser trimming precision |
-
2008
- 2008-01-18 CN CNU2008201012434U patent/CN201166682Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102955070A (en) * | 2011-08-17 | 2013-03-06 | 鸿富锦精密工业（深圳）有限公司 | Resistance measuring circuit |
| CN103439579A (en) * | 2013-08-30 | 2013-12-11 | 昆山奥德鲁自动化技术有限公司 | Economical impedance measurement circuit |
| CN106249049A (en) * | 2016-08-25 | 2016-12-21 | 华东光电集成器件研究所 | A kind of device improving extreme value thick-film resistor laser trimming precision |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20081217 Termination date: 20110118 |