CN1793942A - Direct current potential difference meter having using conversion branch three-range conversion five measuring discs - Google Patents
Direct current potential difference meter having using conversion branch three-range conversion five measuring discs Download PDFInfo
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- CN1793942A CN1793942A CN 200510062233 CN200510062233A CN1793942A CN 1793942 A CN1793942 A CN 1793942A CN 200510062233 CN200510062233 CN 200510062233 CN 200510062233 A CN200510062233 A CN 200510062233A CN 1793942 A CN1793942 A CN 1793942A
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- resistance
- measuring disk
- bracket panel
- dish
- measuring
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Abstract
A DC potential difference meter with five measuring discs and applying conversion branch three-range switch is prepared as using 20 x 40 omega as the first measuring disc, 9 x 8.8 omega as the second and the third measuring discs, 10 x 0.088 omega as the fourth and the fifth measuring discs; using conductive wire to connect resistances on all measuring discs between two measuring end buttons to exclude influence of contact resistance variation and thermo voltage from measuring switch on measuring result; applying integer power of one digit number or two digit number multiplying by ten value of resistance on range switch-over.
Description
Technical field
The present invention relates to measure the instrument of DC voltage.
Background technology
The potential difference meter of current production, when measuring disk has three when above, measure between terminal for two and have switch contact resistance and variation, therefore, even working current is little of 0.1mA, the silver-bearing copper compound substance is not only adopted in the brush of switch and contact, contact area is also done very greatly, variation is brought influence when reducing measuring switch stepping switching, this just makes the instrument volume become big, nonetheless, can not make potential difference meter resolution little to 0.1 μ v, the thermoelectrical potential that also has switch in addition with contact variable thermoelectric potential influence.
Summary of the invention
The problem to be solved in the present invention is, when the step switch that is used for measure portion in the potential difference meter has five, and contact resistance and variation that the measuring switch stepping is switched, the switch thermoelectrical potential does not influence measurement result, makes instrumental resolution reach 0.1 μ v.When range was changed, range conversion was the resistance that one digit number is taken advantage of 10 integral number power with resistance.
Technical scheme of the present invention is such: working current is regulated resistance R P
1, RP
2, RP
3And be used to reduce the fixed resistance R of supply voltage
0, sampling is with setting up resistance and temperature compensation dish RP during to standard
4And five resistor networks of measuring on the step switch are connected in the potential difference meter work loop, and working current is 2.75mA when standardization; It is characterized in that first step dish is made up of I measuring disk and I ' replacement dish, 0～20 indicating value is provided, two resistance above the dish are 20 * 40 Ω, second step disc is by " 0 ", non-resistance between " 1 " two contacts, there is the II measuring disk of 9 * 8.8 Ω resistance 1～10 contact, II ' the replacement dish of 10 * 8.8 Ω reaches and is not connected to resistance, 0 contact is independent, the II that all the other contacts link to each other " the bracket panel composition; the 3rd step disc is by " 9 "; non-resistance between " 10 " two contacts; be the III measuring disk of 9 * 8.8 Ω resistance between 0～9 contact; III ' the replacement dish of 10 * 8.8 Ω and the 10th III that all the other each points of independence connect " the bracket panel composition, the 4th step disc is by all being that the IV measuring disk of 10 * 0.088 Ω resistance and IV ' replacement dish and resistance are the IV of 10 * 0.044 Ω " bracket panel forms; the 5th step disc is the V measuring disk of 10 * 0.088 Ω by resistance; V ' replacement dish and resistance are the V of 10 * 0.044 Ω " bracket panel forms, except that first step disc, the replacement dish of all the other four step discs and the brush of measuring disk are connected to each other; I ' replacement dish brush is connected in the metering circuit positive pole, and I ' replacement is coiled at the 20th and connected 171.116 Ω resistance R
1The back connects IV " bracket panel the 10th point, IV " 0 connection of bracket panel II " bracket panel 0 point; IV " the bracket panel brush connects II " contact of bracket panel except that 0 o'clock, II " the bracket panel brush is divided into two-way, and one the tunnel through 87.12 Ω resistance R
2Back and IV " replacement coils at the 10th and is connected, and another road connects II ' replacement and coils the 10th point, and II measuring disk the 1st o'clock is through 7.92 Ω resistance R
3Back IV measuring disk the 10th connection, 0 of 0 of II measuring disk and IV measuring disk all with 84.444 Ω resistance R
4Connect at one end resistance R
4The other end is connected with 0 of I measuring disk; 0 on I ' replacement dish connects 10155.5 Ω resistance R
5Back and V " 0 of bracket panel is connected; V " the 10th connection of bracket panel III " bracket panel the 10th point; V " the bracket panel brush connects III ' bracket panel all the other each contacts except that the 10th contact, III " the bracket panel brush is divided into two branch roads, the one tunnel through 87.12 Ω resistance R
6The back connects 0 point of V ' replacement dish, and another road connects III ' replacement and coils 0 point, and the 9th of III measuring disk connects 7.92 Ω resistance R
7The back is connected with 0 of V measuring disk, and the 10th of III measuring disk measured at the 10th with the V dish and all be connected with the 20th of I measuring disk; The I ' replacement dish brush and 100 Ω resistance r
1Be connected in parallel on potential difference meter measure portion positive pole, resistance r
1, 900 Ω resistance r in order connect
2, 9000 Ω resistance r
3, resistance r
1With resistance r
2The junction, weld 810 Ω resistance r
4With range selector K
1-1* 0.1 range contact connects resistance r
2With resistance r
3Tie point be connected resistance r with * 1 range contact
3With the 1st measuring disk brush and range selector K
1-1* 10 range contacts connect range selector K
1-1Normally closed contact be connected potential difference meter and measure partly negative pole; Two terminals of measuring disk are anodal to be connected with the 10th of II measuring disk, and negative pole is by galvanometer change-over switch K
2Be connected with 0 of III measuring disk;
By above technical scheme, the measuring disk that five step discs are used for measure portion connects with lead, contact resistance and variation, not in measuring the loop, the just potential difference meter work loop of influence always hinders, because total resistance resistance is very big, so variation can be ignored, the thermoelectric potential influence of several μ V be supply voltage, supply voltage be the volt, how many μ V are thermoelectrical potential be, both differ 10 the 6 power orders of magnitude, and therefore influence can be ignored, even so, even contact resistance variation and thermoelectrical potential are big to the degree of can not ignore, can be by standard is adjusted RP
3Resistance obtain revising, zero potential can increase between V measuring disk and the I measuring disk lead resistance and revise, Just because of this, reduced requirement to switch, after adopting small-sized measurement step switch, it is many that whole instrument overall dimensions reduce, and this instrumental resolution can obtain good repeatability when being 0.1 μ V.Because the range conversion is that one digit number or double figures are taken advantage of 10 integral number power with resistance, available interim standard resistance is revised with resistance range conversion, has improved the accuracy of potential difference meter range ratio.
Description of drawings
Accompanying drawing is a principle of the invention circuit.
Embodiment
In the drawings, by " U
x" anodal through each measuring disk, pass through change-over switch K again
2To " U
x" negative pole is to measure the loop, by positive source through measuring step switch to setting resistance R N and temperature compensation dish RP
4, arrive resistance R then
0, adjustable resistance RP
3, RP
2And RP
1After, getting back to power cathode is the work loop, anodal through change-over switch K from standard cell EN
2, to setting up resistance R N and temperature compensation dish RP
4, be standard loop to the standard cell negative pole again.When five dishes are all thrown " 0 ", left side resistance equals 1100 Ω between two brushes of first step disc, and the right resistance equals 11000 Ω, and total resistance is 1000 Ω between two brushes of first step disc, therefore 10/11 on the left side of total current flows between two brushes of first dish, and 1/11 flows on the right.When second dish threw at 0, second dish equated that with the 4th dish partly resistance in parallel when the 4th dish was thrown different indicating value, the circuit resistance was constant.When second dish is not thrown 0 the time, the 4th dish is thrown different indicating values, the circuit resistance is not having IV " resistance changes during bracket panel; stepping of the 4th every increase of dish; the circuit resistance can increase half resistance of each stepping resistance; for the total resistance of holding circuit constant; at IV " in the bracket panel each stepping reduce same resistance, when second step disc throws 0, the resistance minimum, at this moment allow IV " bracket panel resistance all seals in circuit, makes the circuit resistance constant, in like manner; the right circuit is provided with III " bracket panel and V " bracket panel is that to switch to the total resistance of any indicating value holding circuit constant for the 3rd step disc and the 5th step disc switch; because first dish is made up of resistance identical measuring disk and replacement dish, so what indicating value no matter five dishes throw, circuit always hinders constant;
At * 10 ranges, resistance is by 10 times of resistance r to self resistance between two brushes of first step disc
1, resistance r
2, resistance r
3Series connection back is in parallel, flows through therefore that total current is 10/11 of a potential difference meter electric current between two brushes of first step disc, flows through resistance r
1, r
2, r
3Electric current be 1/11 of potential difference meter working current; When * 1 range, the resistance resistance in series r between two brushes of first step disc
3The back 10 times to the resistance r of mutual series connection
1With resistance r
2Be in parallel, make to flow through the measuring disk electric current and be reduced to * 10 ranges 1/10; When * 0.1 range, total resistance r that connected that hinders between two brushes of first step disc
2With r
3Back and resistance r
1Parallel connection, the resistance after the series connection is r
1109 times, therefore flow through that total current is 1/110 of a potential difference meter working current between two brushes of first step disc, this electric current is * electric current during 10 ranges 1/100.
The potential difference meter working current is 2.75mA, left side electric current 25/11mA between two brushes of first step disc, the right electric current is 2.5/11mA, left side electric current flows through II " is divided into two equal branch roads; when second dish threw at 0, two branch roads that flow through II measuring disk and IV measuring disk separated, when the II measuring disk does not throw 0; flow through II measuring disk branch current and all flow through IV measuring disk resistance, and 10 resistance of IV measuring disk add resistance R behind the bracket panel brush
3Play the effect of the 1st resistance of II measuring disk, when the IV measuring disk is thrown n
4The time, n
4Though～0 ohmically electric current is exactly a left side electric current, can regard two branch currents as and be formed by stacking, can be when therefore calculating with separate computations; In like manner, the right electric current is thrown n at the 5th dish between two brushes of first step disc
5The time, 10～n
5Electric current regard the stack of two branch currents as, take separate computations during calculating.Sampling is 0.04 Ω with setting up resistance R N resistance, when the working current standardization, setting up ohmically pressure drop is 1.018V, the potential difference meter calibrating is carried out in constant temperature enclosure, standard electromotive force of the cell is 1.0186V in the time of 20 ℃, during 20 ℃ of temperature departures, every degree can compensate by-40 μ V, temperature compensation dish RP
4Be 20 * 0.02 Ω, satisfy the national standard of each step value compensation 50 μ V of 0.02 grade of potential difference meter.
Two ends parallel connection after setting up resistance R N series connection temperature compensation dish 10 times of resistance 4076 Ω resistance R, be in order to divide the chief engineer of pouring off to make 1/11 electric current of electric current, can avoid each stepping resistance value of temperature compensation dish is the infinite loop decimal, and this brings convenience resistance measurement.
The minimum calibration of thermometer on the standard cell EN is 0.1 ℃, after according to temperature value the temperature compensation dish being regulated, and K switch
2Point to the right, regulate adjustable resistance RP
1, RP
2And PR
3After, make galvanometer G nulling, potential difference meter working current standardization at this moment, at this moment, the I measuring disk is thrown n
1, the I measuring disk is thrown n
1, the II measuring disk is thrown n
2, the III measuring disk is thrown n
3The IV measuring disk is thrown n
1, the V measuring disk throws n
5
Ux＝25/22×8.8n
2+25/22×0.088n
4+25/11×(80+4.4+0.044)+25/11×40n
1-2.5/11×(20-n
1)×40-2.5/22×(10-n
5)×0.088-2.5/22×(10-n
3)×8.8(mv)
＝10n
2+0.4n
4+2000/11+10+0.1+1000n
1/11-2000/11+100n
1/11-0.1+0.01n
5-10+1n
3(mv)
＝100n
1+10n
2+1n
3+0.1n
4+0.01n
5(mv)
More than be * five measuring disk indicating values of 10 ranges, when * 0.1 range, five measuring disk indicating values are expressed as n
1+ 0.1n
2+ 0.01n
3+ 0.001n
4+ 0.0001n
5(mv).
The potential difference meter operating voltage is 4.5V, because the every joint stable electrical of dry cell kinetic potential between 1.4V～1.65V, all can be adjusted to standard state to the potential difference meter working current for realizing supply voltage at 4.2V～4.95V, gets fixed resistance R
0=247 Ω, adjustable resistance RP
1=20 * 13 Ω, RP
2Be 20 * 0.7 Ω, RP
3Be 20 * 0.04 Ω.
Double-point double-throw switch K
1-2Right * 10, * 1 range carries out the decay of input signal, enters amplifier at the whole signals of * 0.1 range, is (the R of whole signals at * 1 range input signal
10+ R
9)/(R
8+ R
9+ R
10), when * 10 ranges, input signal is the R of whole signals
10/ (R
8+ R
9+ R
10) the diode D of the positive and negative connection of amp.in
1And D
2Be used for input protection, two integrated amplifier OPA128 carry out the differential output of differential input, feedback resistance R
11With R
12Equate, get 1M Ω here, resistance R
13Get 200 Ω, amplified signal shows with reometer G.
Claims (2)
1, a kind of DC potentiometer that has five measuring disk to adopt the conversion of branch three ranges, working current is regulated resistance R P
1, RP
2, RP
3And be used to reduce the fixed resistance R of supply voltage
0, sampling is with setting up resistance and temperature compensation dish RP during to standard
4And five resistor networks of measuring on the step switch are connected in the potential difference meter work loop, and working current is 2.75mA when standardization; It is characterized in that first step dish is made up of I measuring disk and I ' replacement dish, 0～20 indicating value is provided, two resistance above the dish are 20 * 40 Ω, second step disc is by " 0 ", non-resistance between " 1 " two contacts, there is the II measuring disk of 9 * 8.8 Ω resistance 1～10 contact, II ' the replacement dish of 10 * 8.8 Ω reaches and is not connected to resistance, 0 contact is independent, the II that all the other contacts link to each other " the bracket panel composition; the 3rd step disc is by " 9 "; non-resistance between " 10 " two contacts; be the III measuring disk of 9 * 8.8 Ω resistance between 0～9 contact; III ' the replacement dish of 10 * 8.8 Ω and the 10th III that all the other each points of independence connect " the bracket panel composition, the 4th step disc is by all being that the IV measuring disk of 10 * 0.088 Ω resistance and IV ' replacement dish and resistance are the IV of 10 * 0.044 Ω " bracket panel forms; the 5th step disc is the V measuring disk of 10 * 0.088 Ω by resistance; V ' replacement dish and resistance are the V of 10 * 0.044 Ω " bracket panel forms, except that first step disc, the replacement dish of all the other four step discs and the brush of measuring disk are connected to each other; I ' replacement dish brush is connected in the metering circuit positive pole, and I ' replacement is coiled at the 20th and connected 171.116 Ω resistance R
1The back connects IV " bracket panel the 10th point, IV " 0 connection of bracket panel II " bracket panel 0 point; IV " the bracket panel brush connects II " contact of bracket panel except that 0 o'clock, II " the bracket panel brush is divided into two-way, and one the tunnel through 87.12 Ω resistance R
2Back and IV " replacement coils at the 10th and is connected, and another road connects II ' replacement and coils the 10th point, and II measuring disk the 1st o'clock is through 7.92 Ω resistance R
3Back IV measuring disk the 10th connection, 0 of 0 of II measuring disk and IV measuring disk all with 84.444 Ω resistance R
4Connect at one end resistance R
4The other end is connected with 0 of I measuring disk; 0 on I ' replacement dish connects 10155.5 Ω resistance R
5Back and V " 0 of bracket panel is connected; V " the 10th connection of bracket panel III " bracket panel the 10th point; V " the bracket panel brush connects III ' bracket panel all the other each contacts except that the 10th contact, III " the bracket panel brush is divided into two branch roads, the one tunnel through 87.12 Ω resistance R
6The back connects 0 point of V ' replacement dish, and another road connects III ' replacement and coils 0 point, and the 9th of III measuring disk connects 7.92 Ω resistance R
7The back is connected with 0 of V measuring disk, and the 10th of III measuring disk measured at the 10th with the V dish and all be connected with the 20th of I measuring disk; The I ' replacement dish brush and 100 Ω resistance r
1Be connected in parallel on potential difference meter measure portion positive pole, resistance r
1, 900 Ω resistance r in order connect
29000 Ω resistance r
3, resistance r
1With resistance r
2The junction, weld 810 Ω resistance r
4With range selector K
1-1* 0.1 range contact connects resistance r
2With resistance r
3Tie point be connected resistance r with * 1 range contact
3With the 1st measuring disk brush and range selector K
1-1* 10 range contacts connect range selector K
1-1Normally closed contact be connected potential difference meter and measure partly negative pole; Two terminals of measuring disk are anodal to be connected with the 10th of II measuring disk, and negative pole is by galvanometer change-over switch K
2Be connected with 0 of III measuring disk.
2, a kind of DC potentiometer that has five measuring disk to adopt the conversion of branch three ranges according to claim 1, it is characterized in that 407.2 Ω set up connected two ends behind 20 * 0.02 Ω temperature compensation dishes of resistance R N, its 10 times of resistances 407.2 Ω additional resistance R in parallel shunt, and the resistance of having avoided the small step of 0.02 grade of potential difference meter temperature compensation to be worth the stepping resistance of 50 μ V is the infinite loop decimal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510062233 CN1793942A (en) | 2005-12-27 | 2005-12-27 | Direct current potential difference meter having using conversion branch three-range conversion five measuring discs |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200510062233 CN1793942A (en) | 2005-12-27 | 2005-12-27 | Direct current potential difference meter having using conversion branch three-range conversion five measuring discs |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1793942A true CN1793942A (en) | 2006-06-28 |
Family
ID=36805505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510062233 Withdrawn CN1793942A (en) | 2005-12-27 | 2005-12-27 | Direct current potential difference meter having using conversion branch three-range conversion five measuring discs |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1793942A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104101755A (en) * | 2014-07-24 | 2014-10-15 | 富阳兴远仪器仪表经营部 | Direct current potentiometer with five stepping plates |
| CN104111363A (en) * | 2014-07-24 | 2014-10-22 | 富阳兴远仪器仪表经营部 | Potentiometer with temperature compensation table |
| CN104111364A (en) * | 2014-07-24 | 2014-10-22 | 富阳兴远仪器仪表经营部 | Voltage measuring device with five step panels |
| CN104122429A (en) * | 2014-07-24 | 2014-10-29 | 富阳兴远仪器仪表经营部 | Micro-voltage measuring device |
| CN104133102A (en) * | 2014-07-24 | 2014-11-05 | 富阳兴远仪器仪表经营部 | Voltage measurement instrument capable of increasing measurement range by changing work current |
-
2005
- 2005-12-27 CN CN 200510062233 patent/CN1793942A/en not_active Withdrawn
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104101755A (en) * | 2014-07-24 | 2014-10-15 | 富阳兴远仪器仪表经营部 | Direct current potentiometer with five stepping plates |
| CN104111363A (en) * | 2014-07-24 | 2014-10-22 | 富阳兴远仪器仪表经营部 | Potentiometer with temperature compensation table |
| CN104111364A (en) * | 2014-07-24 | 2014-10-22 | 富阳兴远仪器仪表经营部 | Voltage measuring device with five step panels |
| CN104122429A (en) * | 2014-07-24 | 2014-10-29 | 富阳兴远仪器仪表经营部 | Micro-voltage measuring device |
| CN104133102A (en) * | 2014-07-24 | 2014-11-05 | 富阳兴远仪器仪表经营部 | Voltage measurement instrument capable of increasing measurement range by changing work current |
| CN104122429B (en) * | 2014-07-24 | 2016-09-21 | 富阳兴远仪器仪表经营部 | Small voltage measurement apparatus |
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| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C04 | Withdrawal of patent application after publication (patent law 2001) | ||
| WW01 | Invention patent application withdrawn after publication |