CN201576041U

CN201576041U - DC potentiometer

Info

Publication number: CN201576041U
Application number: CN200920295625XU
Authority: CN
Inventors: 方宁妹; 程军
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-12-30
Filing date: 2009-12-30
Publication date: 2010-09-08
Anticipated expiration: 2019-12-30

Abstract

A DC potentiometer used for measuring voltage adopts four measuring panels. Each of four step panels of the DC potentiometer consists of a measuring panel and a replacement panel, and the resistance values of both the measuring panels and the replacement panels are integral power of ten and can be compared in a bridge adopting standard resistance, so that the precision of resistor manufacturing, as well as the measurement accuracy of the whole DC potentiometer is improved; and the four measuring panels are in direct connection through conducting wires, so that switch through switches is not needed and the variation influence caused by the contact between the switches and the resistor does not exist during the measurement of the DC potentiometer.

Description

DC potentiometer

Technical field

The utility model relates to the instrument of measuring DC voltage.

Background technology

Announced the ZL200510062375.1 patent of invention on May 7th, 2008, it is a kind of DC potentiometer that four step discs are arranged, its the 3rd, the 4th step disc respectively has measuring disk, replacement dish and bracket panel are formed, measuring disk is identical with resistance on the replacement dish, resistance of the every increase of measuring disk, the replacement dish just reduces same resistance, because the 3rd step disc is declined in the time of the 10th, the total resistance of circuit changed when the 4th step disc was put different indicating value, the 3rd step disc is put in the time of the 10th, the total resistance of circuit was constant when the 4th step disc was put different indicating value, the 3rd step disc removes for this reason measuring disk, outside the replacement dish, having increased bracket panel distinguishes step disc and puts the 10th and the circuit of declining the 0 10th. two kind of situation and connect, the 4th step disc has also increased bracket panel, has 10 resistance to insert or cut out several resistance respectively above and makes the total resistance of circuit constant.Four measurement disks is connected two and measures between terminal, and the switch contact resistance variation influence on the step disc is got rid of outside the measurement loop.

Because the 3rd, the 4th step disc all has bracket panel, increased the number of plies of the 3rd, the 4th step disc switch, thereby increased the volume of instrument, also make switch and apparatus structure become complicated, if find in the instrument verification process that particularly the 3rd, the 4th step disc measurement data is overproof, the internal layer resistance that revise the 3rd, the 4th step disc switch bothers very much.Application number 200820120442.4 makes progress than ZL200510062375.1, behind the replacement dish brush of first step disc, is divided into two-way but the electric current of these two kinds of DC potentiometer is flowed through, and through each step disc, merges in the measuring disk brush of first step disc; The problem that it brings is that second and third, four resistances of coiling last resistance all are that two same numbers are formed, and resistance is again little, does not have measuring resistance to compare; As use interim standard resistance, the lead-in wire error between two interim standard resistance is just difficult so; Therefore this DC potentiometer second and third, the resistances of four dishes are difficult to do accurately.

The utility model content

The purpose of this utility model is, when DC potential difference during in respect of four step discs, contact resistance and variation that the measuring switch stepping is switched, the switch thermoelectrical potential does not influence measurement result; And three, the 4th step disc is all without bracket panel.Making four resistance on the step disc all be designed to resistance is 10 integral number power, and available standards resistance compares at electric bridge, and manufacturing brings convenience to instrument for this.Simultaneously, it also has two ranges.

The technical solution of the utility model is:

Electric current from DC potentiometer 4.5V working power positive pole through 15/11 Ω resistance R ₅Resistance and single-pole double-throw (SPDT) range selector K to four step discs between node A, the B ₁, set up resistance R N and range of adjustment at the lockable adjustable resistance R of 0～0.5 Ω to 421 Ω again _P3, again to 383 Ω fixed resistance R ₀, through the adjustable resistance R of 0～16 Ω _P2And the adjustable resistance R of 20 15 Ω resistance compositions _P1Get back to the negative pole of working power and form DC potentiometer work loop; From standard cell EN positive pole through being connected to galvanometer G double-point double-throw switch K between two normally closed contacts ₂, to setting up resistance R N and lockable adjustable resistance R _P3, arrive the standard cell negative pole again and form the DC potentiometer standard loop; It is characterized in that first step disc between node A, the B is by each I measuring disk and the I ' replacement dish of being made up of 21 100 Ω resistance, the brush of I measuring disk is communicated with the brush of the I ' replacement dish, second step disc passes through 51 Ω resistance R by each II measuring disk and the II ' replacement dish of being made up of 10 10 Ω resistance between the brush of the brush of II measuring disk and the II ' replacement dish ₂Connect, the 3rd step disc passes through 110 Ω resistance R by each III measuring disk and the III ' replacement dish of being made up of 10 10 Ω resistance between the brush of the brush of III measuring disk and the III ' replacement dish ₃Connect, by IV measuring disk and the IV ' replacement dish that 10 1 Ω resistance are formed, the brush of IV measuring disk is communicated with the brush of the IV ' replacement dish the 4th step disc by each; The DC potentiometer working power is anodal through being divided into two branch roads behind the node C: the one tunnel through 1020 Ω resistance r ₁The back connects single-pole double-throw (SPDT) range selector K ₁* 0.1 range contact, another road is through 15/11 Ω resistance R ₅Be divided into two branch roads again behind node A: left side branch node A connects the I ' replacement and coils the 21st contact, and I measuring disk the 0th contact is by 141 Ω resistance R ₄Back connected node B; The right branch node A is by 1725 Ω resistance R ₁The back connects the II ' replacement and coils the 0th contact, the II ' replacement is coiled the 10th contact and is connected the III ' replacement and coil the 0th contact, the III ' replacement is coiled the 10th contact and is connected the IV ' replacement and coil the 0th contact, IV measuring disk the 10th contact connects III measuring disk the 0th contact, III measuring disk the 10th contact connects II measuring disk the 0th contact, II measuring disk the 10th contact connected node B; Node B and 9180 Ω resistance r ₂An end be connected single-pole double-throw (SPDT) range selector K ₁* 1 range contact, resistance r ₂The other end connect single-pole double-throw (SPDT) range selector K ₁* 0.1 range contact, single-pole double-throw (SPDT) range selector K ₁Normally closed contact connect to set up resistance R N hot end; DC potentiometer is used to connect measured " U _X" two terminals, anodal terminal connects I measuring disk the 21st contact, the negative pole terminal is through being connected to the double-point double-throw switch K of galvanometer G between two normally closed contacts ₂The back is connected with IV measuring disk the 0th contact.

By above technical scheme, the measuring disk that four step discs are used for measure portion connects with lead, and contact resistance and variation be not in measuring the loop, and the just DC potentiometer work loop of influence always hinders, because total resistance resistance is very big, so variation can be ignored; Owing to saved bracket panel, make apparatus structure simple, resistance on measuring disk and the replacement dish all is designed to 10 integral number power, the error of indication of this resistance can be compared with measuring resistance on electric bridge, can improve the resistance precision on the apparatus measures dish, manufacturing brings convenience to instrument for this, thereby and has also improved the measurement accuracy of DC potentiometer complete machine.

Description of drawings

Fig. 1 is a kind of schematic circuit of the present utility model.

In Fig. 1, the adjustable resistance R of 20 * 15 Ω _P1Expression adjustable resistance R _P1Resistance by 20 15 Ω is formed, and in like manner, 21 * 100 Ω represent to be made up of the resistance of 21 100 Ω, and 10 * 10 Ω represent to be made up of the resistance of 10 10 Ω, and 10 * 1 Ω represent to be made up of the resistance of 10 1 Ω.

Embodiment

In Fig. 1, four step discs all are made up of quantity and identical measuring disk and the replacement dish of resistance, and measuring disk increases resistance in every step disc, the replacement dish reduces the resistance of same resistance, otherwise too, so, no matter which kind of indicating value step disc puts, the left side and the right resistance value are constant between node A, B.

Electric current is divided into two the tunnel, the one tunnel and passes through resistance R between the contact of the III ' replacement dish brush contact and contact that III measuring disk brush contacts ₃, another road is through the 4th step disc, and two road resistance all are 110 Ω, and last surface current is also identical, and the contact of the III ' replacement dish brush contact is 55 Ω with resistance between the contact that III measuring disk brush contacts.

Electric current is divided into two the tunnel, the one tunnel through 51 Ω resistance R between the contact of the II ' replacement dish brush contact and contact that II measuring disk brush contacts ₂, another road is through the 3rd and the 4th step disc, and through the resistance of the 3rd and the 4th step disc be: 100 Ω+100 Ω+55 Ω=255 Ω, it is 51 Ω resistance R ₂5 times, work as resistance R ₂On electric current when being 1mA, then the electric current on the 3rd and the 4th step disc respectively is 0.1mA; Resistance is 42.5 Ω between the contact of the II ' replacement dish brush contact and the contact that II measuring disk brush contacts.

When four step discs all during reset, left side resistance value between node A, B equals 2100 Ω+141 Ω=2241 Ω, the right resistance value between node A, B equals 1725 Ω+100 Ω+42.5 Ω=1867.5 Ω, 2241 Ω ÷, 1867.5 Ω=1.2, when the left side electric current between node A, B was 1mA, the right electric current between node A, B was 1.2mA.

All-in resistance is 6/11 * 1867.5 Ω Ω between node A, B, adds 15/11 Ω resistance R ₅To node C, totally 1020 Ω, when * 1 range, resistance is by 10 times of resistance r to self resistance between node C, A, B ₁With resistance r ₂Resistance after series connection institute is in parallel, flows through therefore that electric current is 10/11 of a DC potentiometer total current between node A, B, flows through resistance r ₁With resistance r ₂Electric current be 1/11 of DC potentiometer working current; When * 0.1 range, the resistance resistance in series r between node C, A, B ₂After, with 10 times to resistance r ₁Resistance and resistance r ₁Parallel connection makes resistance r ₁On electric current be 10/11 of DC potentiometer working current, the electric current between node A, B is 1/11 of a DC potentiometer electric current, so electric current reduces to 1/10 on the measuring disk, the amount of making limit is reduced to 1/10.

DC potentiometer standard operation electric current is 2.42mA, and left side electric current is 1mA between node A, B, and the right electric current is 1.2mA.The right electric current is divided into two branch roads after flowing to the contact that contacts with the II ' replacement dish brush, and one the tunnel flows to the contact that contacts with II measuring disk brush through the 3rd and the 4th step disc, and another road is through the II ' replacement dish brush, 51 Ω resistance R ₂To the contact that contacts with II measuring disk brush, be through 51 Ω resistance R through the resistance of the 3rd and the 4th step disc ₂5 times, so, resistance R ₂On electric current be 1mA, be 0.2mA through the total current of the 3rd and the 4th step disc, equate through the resistance value of the 3rd step disc with through the resistance value of the 4th step disc, so these two branch currents all are 0.1mA.

At * 1 range, after the working current standardization, the I measuring disk is put n ₁, the II measuring disk is put n ₂, the III measuring disk is put n ₃, the IV measuring disk is put n ₄, K switch ₂Throw to the left side, be positioned at this moment that voltage is between two terminals of measurement:

U _X＝1×100n ₁+1×141-1.2×10×(10-n ₂)-0.2×10×(n ₂+10-n ₃)-0.1×10×n ₃-0.1×1×(10-n ₄)(mv)

＝100n ₁+141-120+12n ₂-2n ₂-20+2n ₃-n ₃-1+0.1n ₄(mv)

＝100n ₁+10n ₂+n ₃+0.1n ₄(mv)

When * 0.1 range, the indicating value expression formula on four step discs is U _X=10n ₁+ n ₂+ 0.1n ₃+ 0.01n ₄(mv)

The electromotive force of every series-produced standard cell disperses, and between 1.0188V～1.0196V, standardized working current is 2.42mA, and therefore setting up resistance R N gets 421 Ω, adds the lockable adjustable resistance R of 0～0.5 Ω _P3, variation range that can the coverage criteria cell emf.

Electromotive force was about 1.65V when dry cell was new, just abandon when following to 1.4V with old, in order to make dry cell under new, former affection condition, can both make the working current of DC potentiometer be adjusted to standardization, the DC potentiometer operating voltage is 4.5V, adopt three groups of dry cell series connection, form adjustable resistance R by 20 15 Ω resistance _P1, adjustable resistance R _P2Be 0～18 Ω and one the 383 Ω resistance R of connecting ₀

The standard operation electric current of DC potentiometer is to determine like this, at " U _x" two of two ends measure terminals and connect 2V normal voltage signal, range selector K by polarity ₁Put in " * 1 " range, K switch ₂Throw to the left side, the total indicating value of step disc is identical with standard voltage value, regulates resistance R by regulating working current _P1And R _P2, make the galvanometer nulling, again with K switch ₂Throw to the right, sampling is 421 Ω with the resistance of setting up resistance R N, and 0～0.5 Ω adjustable resistance R has connected _P3Regulate adjustable resistance R _P3, make galvanometer nulling once more, again with K switch ₂Throw to the left side, regulate adjustable resistance R _P2, make the galvanometer nulling, again with K switch ₂Throw to the right, regulate adjustable resistance R _P3, make the galvanometer nulling, work as K switch ₂Throw to the left side and throw when the equal nulling of galvanometer is not regulated on the right, the working current that DC potentiometer is described is promptly set up ohmically pressure drop and is equated with the electromotive force of unsaturated standard cell EN, at this moment with adjustable resistance R with regard to standardization _P3Locking, this DC potentiometer is from now on just as standard.

Claims

1. DC potentiometer that four measurement disks is arranged, electric current from DC potentiometer 4.5V working power positive pole through 15/11 Ω resistance R ₅Resistance and single-pole double-throw (SPDT) range selector K to four step discs between node A, the B ₁, set up resistance R N and range of adjustment at the lockable adjustable resistance R of 0～0.5 Ω to 421 Ω again _P3, again to 383 Ω fixed resistance R ₀, through the adjustable resistance R of 0～16 Ω _P2And the adjustable resistance R of 20 15 Ω resistance compositions _P1Get back to the negative pole of working power and form DC potentiometer work loop; From standard cell EN positive pole through being connected to galvanometer G double-point double-throw switch K between two normally closed contacts ₂, to setting up resistance R N and lockable adjustable resistance R _P3, arrive the standard cell negative pole again and form the DC potentiometer standard loop; It is characterized in that first step disc between node A, the B is by each I measuring disk and the I ' replacement dish of being made up of 21 100 Ω resistance, the brush of I measuring disk is communicated with the brush of the I ' replacement dish, second step disc passes through 51 Ω resistance R by each II measuring disk and the II ' replacement dish of being made up of 10 10 Ω resistance between the brush of the brush of II measuring disk and the II ' replacement dish ₂Connect, the 3rd step disc passes through 110 Ω resistance R by each III measuring disk and the III ' replacement dish of being made up of 10 10 Ω resistance between the brush of the brush of III measuring disk and the III ' replacement dish ₃Connect, by IV measuring disk and the IV ' replacement dish that 10 1 Ω resistance are formed, the brush of IV measuring disk is communicated with the brush of the IV ' replacement dish the 4th step disc by each; The DC potentiometer working power is anodal through being divided into two branch roads behind the node C: the one tunnel through 1020 Ω resistance r ₁The back connects single-pole double-throw (SPDT) range selector K ₁* 0.1 range contact, another road is through 15/11 Ω resistance R ₅Be divided into two branch roads again behind node A: left side branch node A connects the I ' replacement and coils the 21st contact, and I measuring disk the 0th contact is by 141 Ω resistance R ₄Back connected node B; The right branch node A is by 1725 Ω resistance R ₁The back connects the II ' replacement and coils the 0th contact, the II ' replacement is coiled the 10th contact and is connected the III ' replacement and coil the 0th contact, the III ' replacement is coiled the 10th contact and is connected the IV ' replacement and coil the 0th contact, IV measuring disk the 10th contact connects III measuring disk the 0th contact, III measuring disk the 10th contact connects II measuring disk the 0th contact, II measuring disk the 10th contact connected node B; Node B and 9180 Ω resistance r ₂An end be connected single-pole double-throw (SPDT) range selector K ₁* 1 range contact, resistance r ₂The other end connect single-pole double-throw (SPDT) range selector K ₁* 0.1 range contact, single-pole double-throw (SPDT) range selector K ₁Normally closed contact connect to set up resistance R N hot end; DC potentiometer is used to connect measured " U _X" two terminals, anodal terminal connects I measuring disk the 21st contact, the negative pole terminal is through being connected to the double-point double-throw switch K of galvanometer G between two normally closed contacts ₂The back is connected with IV measuring disk the 0th contact.