CN100410668C - Four-measuring range potential difference meter with four measurng disks and reversing branch - Google Patents

Four-measuring range potential difference meter with four measurng disks and reversing branch Download PDF

Info

Publication number
CN100410668C
CN100410668C CNB2005100623696A CN200510062369A CN100410668C CN 100410668 C CN100410668 C CN 100410668C CN B2005100623696 A CNB2005100623696 A CN B2005100623696A CN 200510062369 A CN200510062369 A CN 200510062369A CN 100410668 C CN100410668 C CN 100410668C
Authority
CN
China
Prior art keywords
resistance
range
measuring disk
measuring
iii
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.)
Expired - Fee Related
Application number
CNB2005100623696A
Other languages
Chinese (zh)
Other versions
CN1818674A (en
Inventor
骆乃光
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to CNB2005100623696A priority Critical patent/CN100410668C/en
Publication of CN1818674A publication Critical patent/CN1818674A/en
Application granted granted Critical
Publication of CN100410668C publication Critical patent/CN100410668C/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Measurement Of Resistance Or Impedance (AREA)

Abstract

The present invention relates to a four-measuring range potential difference meter with four measurng disks and a reversing branch, and is used for measuring voltage. The present invention uses 20*100 omega as a first measuring disk, uses 10*11 omega as a second measuring disk, uses 9*22 omega as a third measuring disk, and uses 10*2.2 omega as a fourth measuring disk. The present invention is provided with a converting switch which does not influence a measuring result. Two measuring end buttons and the four measuring disks of the potential difference meter are directly connected by conducting wires. Contact resistance, variation and thermoelectric potential of a measuring stepping switch are all excluded out of the measuring result. If zero potential is large, negative potential can be enlarged, which leads the zero potential to be compensated. The potential difference meter adopts four resistors which respectively have a resistance value which is an integer power of a one-digit number or a two-digit number multiplied by ten for measuring range conversion.

Description

There is four measurement disks to adopt the four-range potentiometer of branch
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 the measuring switch stepping and switching, and this just makes the instrument volume become big, 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 being used for measure portion in the potential difference meter four step discs arranged, 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 or two figure places are taken advantage of 10 integral number power with resistance.
Technical scheme of the present invention is such: it has working current to regulate resistance R P 1And RP 2, be used to reduce the fixed resistance R of supply voltage 0, the 926 Ω setting resistance R N of sampling usefulness and range of adjustment are at the adjustable resistance RP of 0～1.3 Ω during to standard 3, and the resistor network on four step discs is connected in the potential difference meter work loop, when setting up ohmically voltage drop and equating by the interior affix difficulty of the potential difference meter after the resistance R current limliting, its working current equals 1.1mA; Signal amplifies employing two OPA128, resistances and all equals 1M Ω resistance R 1With resistance R 2, 200 Ω resistance R 3The amplifying circuit of forming the differential output of differential input, input end is with the diode D of positive and negative connection 1And D 2Protect, amplified signal shows by reometer G; Three cuttves, four throw switch K 1-3Be used for applied signal voltage and when different range, decay resistance R 4, R 5, R 6, R 7On signal voltage when * 0.01 range, all enter amplifying circuit; When * 0.1 range, applied signal voltage is (R 5+ R 6+ R 7)/(R 4+ R 5+ R 6+ R 7), when * 1 range, applied signal voltage is (R 6+ R 7)/(R 4+ R 5+ R 6+ R 7), when * 10 ranges, applied signal voltage is R 7/ (R 4+ R 5+ R 6+ R 7); First step disc is made up of I measuring disk that 20 * 100 Ω are respectively arranged and the I ' replacement dish, second step disc is made up of II measuring disk that 10 * 11 Ω are respectively arranged and the II ' replacement dish, the 3rd step disc is by " 9 ", non-resistance between " 10 " two contacts, these two contacts disconnect, all the other contacts are by the III measuring disk of 9 * 22 Ω resistance of resistance connection, 10 * 22 Ω the III ' replacement dishes are arranged and be not welded with resistance, the 10th independence, the III that all the other contacts connect " bracket panel forms; the 4th step disc is by being all IV measuring disk and the IV ' replacement dish that 10 * 2.2 Ω resistance form and the IV that 10 * 1.1 Ω resistance are arranged " bracket panel forms, except that first step disc, the brush of the measuring disk on all the other step discs oneself dish is connected with the brush of replacement dish; The I ' replacement is coiled and was connected the II ' replacement by 977.9 Ω resistance at the 20th o'clock and coil the 10th point, after connecting one 212.1 Ω resistance, the 0th of II measuring disk be connected with the 0th of I measuring disk, the I ' replacement is coiled at the 0th and is connected IV after connecting one 30879 Ω resistance " bracket panel the 0th point; IV " the 10th of bracket panel and III " the 10th of bracket panel be connected; IV " the bracket panel brush connects III " bracket panel all contacts except that the 10th contact; and III " bracket panel brush one tunnel connects the III ' replacement and coils the 0th point, another road is coiled at the 0th with the IV ' replacement after by 198 Ω resistance and is connected, and the 10th of III measuring disk directly is connected with the 20th of I measuring disk; The 9th of III measuring disk connects IV measuring disk the 0th point, and the 10th of IV measuring disk is connected with the 20th of I measuring disk; The I ' replacement dish brush and 30 Ω resistance r 1Be connected in parallel on potential difference meter measure portion positive pole, resistance r 1The other end and 270 Ω resistance r 3Be connected three cuttves four and throw range selector K 1-1* 0.01 range contact, resistance r 3The other end and 2700 Ω resistance r 5Be connected three cuttves four and throw range selector K 1-1* 0.1 range contact, resistance r 5The other end and 27000 Ω resistance r 6Be connected three cuttves four and throw range selector K 1-1 * 1 range contact, 27000 Ω resistance r 6The other end and I measuring disk brush are connected three cuttves four and throw range selector K 1-1* 10 range contacts, 267.3 Ω resistance r 2An end be connected three cuttves four and throw range selector K 1-2* 0.01 range contact, resistance r 2The other end and 2430 Ω resistance r 4An end connect range selector K 1-2* 0.1 range contact, 2430 Ω resistance r 4The other end be connected K 1-2* 1 range contact, K 1-2* 1 range contact and K 1-2* 10 range contacts are connected the measure portion negative pole, three cuttves, four throw switch K 1-1With K 1-2Two normally closed contact short circuits, potential difference meter is used to connect measured U XTwo terminals, anodal terminal is connected with the 10th of II measuring disk, and the negative pole terminal is by galvanometer change-over switch K 2Be connected with the 0th of III measuring disk.
By above technical scheme, the measuring disk that four 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 2Resistance obtain revising, zero potential can be revised by increasing between IV measuring disk and the I measuring disk lead resistance, so 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
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 RP 3, arrive resistance R then 0, adjustable resistance 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 RP 3, be standard loop to the standard cell negative pole again.When four dishes are all thrown " 0 ", left side resistance is 3300 Ω between two brushes of first step disc, and the right resistance equals 33000 Ω, and total resistance is 3000 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 the 3rd dish threw at the 10th, the 4th dish equated that with the 3rd dish partly resistance in parallel when the 4th dish was thrown different indicating value, the circuit resistance was constant.When the 3rd dish is not thrown at the 10th, the 4th dish is thrown different indicating values, the circuit resistance is not having IV " resistance changes during bracket panel; the 4th dish every increase stepping, circuit resistance can reduce half resistance of each stepping resistance, for the total resistance of holding circuit constant; at IV " in the bracket panel each stepping increase same resistance, resistance minimum when the 3rd step disc throws at the 10th, " bracket panel resistance all seals in circuit, makes the circuit resistance constant at this moment to allow IV.Because second dish and first dish are formed by resistance identical measuring disk and replacement dish, so what indicating value no matter four 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 3, resistance r 5, r 6Series 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 3, r 5, r 6Electric 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 6The back 10 times to the resistance r of mutual series connection 1And resistance r 3, resistance r 5Be 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 6With r 5Back and resistance r 1Series connection r 3The back is in parallel, and the resistance after the series connection is r 1Add r 3109 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 resistance that this range reduces is by sealing in resistance r 4The total resistance of holding circuit afterwards is constant.When * 0.01 range, the resistance r that connected of the resistance between two brushes of first step disc 6, resistance r 5, resistance r 3Back and resistance r 1Parallel connection, the resistance after the series connection are resistance r 11099 times, making the electric current that flows through between two brushes of first step disc is 1/1100 of potential difference meter working current, the amount of making limit is reduced to * per mille during 10 ranges, the resistance that this range reduces is by resistance r 2Resistance in series r 4The total resistance of holding circuit afterwards is constant.
Basic range potential difference meter standard operation electric current is 1.1mA, left side electric current 10/11mA between two brushes of first step disc, the right electric current is 1/11mA, the right electric current flows through III " is divided into two equal branch roads; when the 3rd dish throws at the 10th; two branch roads that flow through III measuring disk and IV measuring disk separate; when the III measuring disk does not throw at the 10th; flow through III measuring disk branch current and all flow through IV measuring disk resistance; 10 resistance of IV measuring disk play the effect of the 10th resistance of III measuring disk, when the IV measuring disk is thrown n behind the bracket panel brush 4The time, n 4Though～10 ohmically electric currents are exactly the right electric current, can regard two branch currents as and be formed by stacking, can be with separate computations when therefore calculating;
The standard operation electric current is to determine like this, at " U X" two of two ends measure terminals and connect normal voltage near full scale, K switch by polarity 2Throw to the left side, the measuring disk indicating value is identical with standard voltage value, regulates resistance R P by regulating working current 1And RP 2, make the galvanometer nulling, again with K switch 2Throw to the right, sampling is 926 Ω with the resistance of setting up resistance R N, and 0～1.3 Ω adjustable resistance RP has connected 3, regulate RP 3, make galvanometer nulling once more, again with K switch 2Throw to the left side, regulate RP 2Make the galvanometer nulling, again with K switch 2Throw to the right and regulate RP 3Make the galvanometer nulling, when switch points to the left side and the right and do not regulate the equal nulling of galvanometer, the standardization of potential difference meter working current is described, promptly set up ohmically pressure drop and equate, at this moment with RP with the electromotive force of unsaturated standard cell EN 3Locking, this potential difference meter is from now on just as standard.After the working current standardization, the I measuring disk is thrown n 1, the II measuring disk is thrown n 2, the III measuring disk is thrown n 3, the IV measuring disk is thrown n 4, K switch 2Throw to the left side, be positioned at this moment that voltage is between two terminals of measurement:
Ux＝10/11×11n 2+10/11×(200+11+1.1)×10/11×100n 1-1/11×(20-n 1)×100-1/22×(10-n 4)×2.2-1/22×(10-n 3)×22(mv)
＝10n 2+2000/11+10+1+1000n 1/11-2000/11+100n 1/11-1+0.1n 4-10+1n 3(mv)
＝100n 1+10n 2+1n 3+0.1n 4(mv)
More than press basic range and calculate, when * 0.01 range
U X=0.1n 1+ 0.01n 2+ 0.001n 3+ 0.0001n 4At this moment minimum step is 0.1 μ V.
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=163 Ω, adjustable resistance RP 1=20 * 34 Ω, RP 2Be 0～36 Ω.
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 1With R 2Equate, get 1M Ω here, resistance R 3Get 200 Ω, amplified signal shows that with reometer G resistance R is used for the standard loop current limliting, three cuttves, four throw switch K 1-3The pair amplifier input signal is decayed resistance R when being used for different range 4, resistance R 5, resistance R 6, resistance R 7On signal voltage when * 0.01 range, all enter amplifying circuit, when * 0.1 range, applied signal voltage is (R 5+ R 6+ R 7)/(R 4+ R 5+ R 6+ R 7), applied signal voltage is (R when * 1 range 6+ R 7)/(R 4+ R 5+ R 6+ R 7), when * 10 ranges, applied signal voltage is R 7/ (R 4+ R 5+ R 6+ R 7).

Claims (1)

1. four-range potentiometer that has four measurement disks to adopt branch, it has working current to regulate resistance R P 1And RP 2, be used to reduce the fixed resistance R of supply voltage 0, the 926 Ω setting resistance R N of sampling usefulness and range of adjustment are at the adjustable resistance RP of 0～1.3 Ω during to standard 3, the resistor network that reaches on four step discs is connected in the potential difference meter work loop, and when setting up ohmically voltage drop and equating by the potential difference meter internal attachment standard after the resistance R current limliting, its working current equals 1.1mA; Signal amplifies employing two OPA128, resistances and all equals 1M Ω resistance R 1With resistance R 2, 200 Ω resistance R 3The amplifying circuit of forming the differential output of differential input, input end is with the diode D of positive and negative connection 1And D 2Protect, amplified signal shows by reometer G; Three cuttves, four throw switch K 1-3Be used for applied signal voltage and when different range, decay resistance R 4, R 5, R 6, R 7On signal voltage when * 0.01 range, all enter amplifying circuit; When * 0.1 range, applied signal voltage is (R 5+ R 6+ R 7)/(R 4+ R 5+ R 6+ R 7), when * 1 range, applied signal voltage is (R 6+ R 7)/(R 4+ R 5+ R 6+ R 7), when * 10 ranges, applied signal voltage is R 7/ (R 4+ R 5+ R 6+ R 7); This four-range potentiometer that has four measurement disks to adopt branch is characterised in that first step disc is made up of I measuring disk that 20 * 100 Ω are respectively arranged and the I ' replacement dish, second step disc is made up of II measuring disk that 10 * 11 Ω are respectively arranged and the II ' replacement dish, the 3rd step disc is by " 9 ", non-resistance between " 10 " two contacts, these two contacts disconnect, all the other contacts are by the III measuring disk of 9 * 22 Ω resistance of resistance connection, 10 * 22 Ω the III ' replacement dishes are arranged and be not welded with resistance, the 10th independence, the III that all the other contacts connect " bracket panel forms; the 4th step disc is by being all IV measuring disk and the IV ' replacement dish that 10 * 2.2 Ω resistance form and the IV that 10 * 1.1 Ω resistance are arranged " bracket panel forms, except that first step disc, the brush of the measuring disk on all the other step discs oneself dish is connected with the brush of replacement dish; The I ' replacement is coiled and was connected the II ' replacement by 977.9 Ω resistance at the 20th o'clock and coil the 10th point, after connecting one 212.1 Ω resistance, the 0th of II measuring disk be connected with the 0th of I measuring disk, the I ' replacement is coiled at the 0th and is connected IV after connecting one 30879 Ω resistance " bracket panel the 0th point; IV " the 10th of bracket panel and III " the 10th of bracket panel be connected; IV " the bracket panel brush connects III " bracket panel all contacts except that the 10th contact; and III " bracket panel brush one tunnel connects the III ' replacement and coils the 0th point, another road is coiled at the 0th with the IV ' replacement after by 198 Ω resistance and is connected, and the 10th of III measuring disk directly is connected with the 20th of I measuring disk; The 9th of III measuring disk connects IV measuring disk the 0th point, and the 10th of IV measuring disk is connected with the 20th of I measuring disk; The I ' replacement dish brush and 30 Ω resistance r 1Be connected in parallel on potential difference meter measure portion positive pole, resistance r 1The other end and 270 Ω resistance r 3Be connected three cuttves four and throw range selector K 1-1* 0.01 range contact, resistance r 3The other end and 2700 Ω resistance r 5Be connected three cuttves four and throw range selector K 1-1* 0.1 range contact, resistance r 5The other end and 27000 Ω resistance r 6Be connected three cuttves four and throw range selector K 1-1* 1 range contact, 27000 Ω resistance r 6The other end and I measuring disk brush are connected three cuttves four and throw range selector K 1-1* 10 range contacts, 267.3 Ω resistance r 2An end be connected three cuttves four and throw range selector K 1-2* 0.01 range contact, resistance r 2The other end and 2430 Ω resistance r 4An end connect range selector K 1-2* 0.1 range contact, 2430 Ω resistance r 4The other end be connected K 1-2* 1 range contact, K 1-2* 1 range contact and K 1-2* 10 range contacts are connected the measure portion negative pole, three cuttves, four throw switch K 1-1With K 1-2Two normally closed contact short circuits, potential difference meter is used to connect measured U xTwo terminals, anodal terminal is connected with the 10th of II measuring disk, and the negative pole terminal is by galvanometer change-over switch K 2Be connected with the 0th of III measuring disk.
CNB2005100623696A 2005-12-30 2005-12-30 Four-measuring range potential difference meter with four measurng disks and reversing branch Expired - Fee Related CN100410668C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CNB2005100623696A CN100410668C (en) 2005-12-30 2005-12-30 Four-measuring range potential difference meter with four measurng disks and reversing branch

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CNB2005100623696A CN100410668C (en) 2005-12-30 2005-12-30 Four-measuring range potential difference meter with four measurng disks and reversing branch

Publications (2)

Publication Number Publication Date
CN1818674A CN1818674A (en) 2006-08-16
CN100410668C true CN100410668C (en) 2008-08-13

Family

ID=36918768

Family Applications (1)

Application Number Title Priority Date Filing Date
CNB2005100623696A Expired - Fee Related CN100410668C (en) 2005-12-30 2005-12-30 Four-measuring range potential difference meter with four measurng disks and reversing branch

Country Status (1)

Country Link
CN (1) CN100410668C (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101034112B (en) * 2007-04-03 2010-05-26 程军 Four measuring ranges potentiometer
CN101034104B (en) * 2007-04-03 2010-04-21 方勇 Four measuring ranges portable potentiometer
CN101063694B (en) * 2007-05-29 2010-06-02 张春雷 Voltage measurement instrument

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0280303A2 (en) * 1987-02-26 1988-08-31 Veb Kombinat Wolle Und Seide Method and circuit for the automatic measuring of direct currents
CN1673754A (en) * 2005-04-22 2005-09-28 骆乃光 Portable potential difference meter
CN1673755A (en) * 2005-04-22 2005-09-28 骆乃光 Potential difference meter with seven bit reading
CN1673753A (en) * 2005-04-22 2005-09-28 骆乃光 Portable potential difference meter with high resolution ratio

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0280303A2 (en) * 1987-02-26 1988-08-31 Veb Kombinat Wolle Und Seide Method and circuit for the automatic measuring of direct currents
CN1673754A (en) * 2005-04-22 2005-09-28 骆乃光 Portable potential difference meter
CN1673755A (en) * 2005-04-22 2005-09-28 骆乃光 Potential difference meter with seven bit reading
CN1673753A (en) * 2005-04-22 2005-09-28 骆乃光 Portable potential difference meter with high resolution ratio

Also Published As

Publication number Publication date
CN1818674A (en) 2006-08-16

Similar Documents

Publication Publication Date Title
CN100410668C (en) Four-measuring range potential difference meter with four measurng disks and reversing branch
CN1793960A (en) Potential difference meter using divided branch bimeasuring range conversion having four measuring discs
CN100394194C (en) Direct current potential difference meter using conversion branch two measuring range conversion
CN1793942A (en) Direct current potential difference meter having using conversion branch three-range conversion five measuring discs
CN1793953A (en) Three measuring range direct current potential difference meter having five mensuring discs using divided branch
CN100386631C (en) Four measuring disk DC potential difference meter with four-measuring range conversions and reversing branch
CN100386632C (en) Three-measuring range DC potential difference meter with fiver reading digits and sliding wire disk
CN100367037C (en) Three-range switching DC potentiometer having four measurement disks and employing shunt branch
CN100394196C (en) Three measuring range potential difference meter using converter branch having five digit reading
CN1991379B (en) Four-range potentiometer utilizing branch line having four measuring plates
CN100394197C (en) Three-measuring range and five-reading DC potential difference meter
CN100375901C (en) Three-measuring range DC potential difference meter with five's place reading utilizing, shunt branch
CN100386634C (en) Two-measuring range DC potential difference meter
CN100445752C (en) Three-measuring range DC potential difference meter with five measuring disc utilizing conversion branch
CN100375900C (en) Direct current potential diffenence meter having five measuring discs using divided branch three measuring range conversion
CN100445753C (en) Two-measuring range potential differencemeter with five's place reading utilizing shunt branch
CN100394193C (en) Potential difference meter having four measuring discs using inversion branch bimeasuring range conversion
CN100445751C (en) Two-range switching DC potentiometer having five-digit reading and employing transposition branch
CN1793949B (en) Three measuring range potential difference meter using conversion branch having four measuring discs
CN100394195C (en) Three measuring range portable potential difference meter using divided branch
CN100371720C (en) Two-range potentiometer having five measurement disks and employing transposition branch
CN1793952A (en) Potential difference meter using divided branch three measuring range conversion having five measuring discs
CN100386630C (en) Bimeasuring range pitantial difference mater using divided branch having five measuring discs
CN1793951A (en) Bimeasuring range direct current potential difference meter using divided branch having four measuring discs
CN1991383A (en) Four-range potentiometer

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
C17 Cessation of patent right
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20080813

Termination date: 20100201