CN1425923A

CN1425923A - Multiple measuring range DC potential difference meter

Info

Publication number: CN1425923A
Application number: CN 01142334
Authority: CN
Inventors: 骆乃光
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-08
Filing date: 2001-12-08
Publication date: 2003-06-25

Abstract

The multiple measuring range DC potential difference meter consists of working current regulating resistor, range proportion switches and measuring disc. It has several measuring ranges for measuring different voltage. In order to decreasing measurement error, electronic reference source voltage dividing method is adopted, where there is always one resistor string shared by the measuring loop and the standard loop.

Description

Multiple measuring range DC potential difference meter

The present invention relates to a kind of equipment that DC voltage is measured.

All are at all size direct current measurement potential difference meters of production now, there is not public resistance as multiple measuring range DC potential difference meter standard loops such as market UJ36a on sale, UJ33a and measurement loop, temperature variation makes resistance change like this, causes that measuring error increases; The error of range conversion directly causes measuring error.High potentials such as market UJ25 on sale, UJ24, the measurement loop and the standard loop of single measuring range DC potential difference meter have 1.018 volts to be public resistance, measure the loop resistance value like this and change, and standard loop and then changes with direction of error, can offset fractional error, but it can not there be a plurality of ranges.

The purpose of this invention is to provide a kind of multiple measuring range DC potential difference meter, the resistance that the most of voltage measurement scope of loop and standard loop of measuring in all ranges is used is public; Like this, can effectively reduce the measuring error that range conversion and temperature variation cause.

The present invention realizes like this: the DC potentiometer standard adopts electronics reference source, a collection of divider resistance is loaded onto at the DC potentiometer that links to each other with reference source " standard " two ends, and carry out the intrinsic standoff ratio conversion with switch, this switch and range selector are synchronous, proportionate relationship between the divider resistance and range ratio relationship consistency, like this, when range switch is transformed into different range, just have different voltage reference values.Reference value when DC potentiometer range first dish voltage reading numerical value should be more than or equal to this range after the dividing potential drop, choose a point with reference value synonym value in DC potentiometer first dish, this point and the resistance of first measuring disk between zero point are connected in the standard loop as public resistance.Adopt the potential difference meter of dividing potential drop circuit all to be suitable for for first dish, and first dish adopt the potential difference meter of dividing potential drop circuit to account for the overwhelming majority.

Existing 0.01 grade of DC potentiometer guarantees that the accuracy temperature range limit is 20 ± 5 ℃, 0.1 the level DC potentiometer guarantees that the accuracy temperature range limit is 20 ± 10 ℃, adopt the method for the public resistance of first dish, reduced temperature significantly and can ignore substantially the influence and the range error of DC potentiometer accuracy of measurement; Moreover electronics reference source can be accomplished temperature coefficient easily less than 3PPM/ ℃, and it is the most important assurance that the present invention has practical value.

The present invention will be illustrated in conjunction with the accompanying drawings by preferred examples, wherein:

Fig. 1 is the low potential potentiometer circuit figure of simple dividing potential drop circuit

Fig. 2 is the DC potentiometer circuit diagram that adopts series connection replacement circuit

With reference to accompanying drawing, below be explanation to specific embodiment.

In the drawings, DC potentiometer working

power input end

1 and 2, measuring junction 3 and 4, standard input end 5 and 6, resistance 14 is used for fixing pressure, working current is regulated the size that resistance 13 is used for regulating working current, resistance 15 and resistance 16 be used for range conversion wherein resistance 16 be that 9 times of resistance 15 are whole, and the resistance of resistance 15 equals the resistance that resistance 18 adds resistance 17.Potential difference meter the 1st dish is resistance 18, and it is in series by 12 resistance of equivalence, with the 2nd measuring disk resistance 17 are slide wire resistances.When range switch 10 pointed to * 10, the resistance that resistance 15 adds resistance 16 was 10 times of two total resistances of measuring disk of potential difference meter; When switch 10 pointed to * 1, total resistance that the resistance of two measuring disk adds resistance 16 was 10 times of resistance of resistance 15; Differ 10 times because flow through two ranges of measuring disk electric current, so DC potential difference is in respect of two ranges of * 10 and * 1.After electronics reference source is connected to standard input end 5 and 6, because its voltage is much larger than the low potential DC potentiometer first dish voltage, therefore with resistance 7 step-downs, the pressure drop that resistance 8 is added on the resistance 9 equals DC potentiometer 0～10 resistance drop of first dish when * 10 ranges, and to make resistance 8 be 9 times of resistance 9 resistance values, and make dividing potential drop ratio switch 11 and range ratio switch 10 synchronous.When resistance 15 or resistance 16 cause proportional error, or temperature is when causing the measuring disk error, double-point double-throw switch 12 inserts standard loop, galvanometer 19 just can balance, therefore to regulate adjustable resistor 14, make and flow through the one the second two measuring disk electric currents and return to exact value, galvanometer 19 is restored balance.

Fig. 2 is another fact Example of the present invention, and working

power input end

1 and 2 input voltages are 3V, and working current is regulated resistance 13 and is made of range of adjustment 0～520 Ω every grade 26 Ω of 20 grades of step switch; Working current is regulated resistance 14 by 20 grades of step switch, and every grade 1.5 Ω forms range of adjustment 0～30 Ω.Working current is regulated resistance 15 and is made up of 0～2 Ω slide wire resistance.The total range of adjustment of resistance is 0～552 Ω.First measuring disk is a resistance 20, and it is in series by 23 100 Ω resistance; Second measuring disk is a resistance 21, and it is in series by 10 10 Ω resistance, and with the replacement dish that has of second measuring disk interlock, its resistance 22 constitutes with resistance 21, is in series by 10 10 Ω resistance.Enter a resistance when measuring the loop, the replacement dish just cuts out the resistance that resistance is identical, and is constant with resistance between maintenance A, B.The 3rd measuring disk is a resistance 23, and it also has a replacement dish.Resistance 23 is in series by 10 1 Ω resistance with this replacement dish resistance 24, and the 3rd measuring disk is made up of 20 resistance 25, its resistance=0.05 Ω.Therefore, A B measurements branch road resistance is 2411 Ω.Resistance 16 resistances are 241.1 Ω, and resistance 18 resistances are 2169.9 Ω, and resistance 19 is 21699 Ω, therefore; Range switch 10 fingers * 10, * 1, * 0.1 o'clock, the ratio that electric current flows through measuring disk is 10: 1: 0.1.Because when * 0.1 range, the parallel resistance resistance drops to 238.91 Ω by 2191.818 Ω between A, C, therefore insert resistance 17, resistance value is 1952.91 Ω, and is constant with resistance between guarantor A, C.Resistance 26 is 262 Ω, to raise operating voltage to 2.7V, avoids working on behind the battery failure, causes and measures trouble.This circuit working electric current is 1.1mA, regulate

resistance

13,14 and 15 by working current, operating voltage is regulated between 2.7 to 3.3V, the holding circuit working current is 1.1mA, measuring junction 3 and 4, maximum measuring voltage are respectively 2.411V, 241.1mV, 24.11mV.

Standard input end 5 and 6 input reference voltages are 2V, and divider resistance 7,8 and 9 is formed the dividing potential drop proportion resistor, and resistance 9 is 100 Ω, and resistance 8 is 900 Ω, and resistance 7 is 9000 Ω.First measuring disk links to each other with input end 6 zero point, first measuring disk 20 links to each other with intrinsic standoff ratio switch 11, intrinsic standoff ratio switch 11 is synchronous when the range switch was changed by 10: 1: 0.1 with range selector 10, and the intrinsic standoff ratio of intrinsic standoff ratio switch is also by 10: 1: 0.1 dividing potential drops.

In this circuit, proportional error, resistance 20 temperature variation can switch to standard loop to galvanometer 27 by double-point double-throw switch 12 and carry out balance check, and regulate resistance adjustment by working current and eliminate error, thereby to resistance 16,18 and 19, and 20 resistance 20 all can lower the requirement, concentrate and grab measuring resistance 7,8 and 9, require them to use same material method coiling of the same race, processing, and through unaccelerated aging, measure the identical machine on a group that is classified as before the assembling through temperature coefficient.

Claims

1. multiple measuring range DC potential difference meter, regulating resistance, range conversion resistance and first dish by working current adopts the measuring disk of dividing potential drop circuit to form, it is characterized in that DC potentiometer " standard " input end has a string divider resistance that reference voltage is carried out dividing potential drop, intrinsic standoff ratio equals range conversion ratio, and range selector (10) is synchronous with partial pressure switch (11), to guarantee any range standard loop and measurement loop first dish partly public resistance is arranged.

2. multiple measuring range DC potential difference meter according to claim 1, what it is characterized in that the standard of being input to (5) and (6) two ends is the electronics reference power supply.