SU373650A1 - ELECTRIC CONDUCTIVITY MEASURE - Google Patents

Description

The invention is related to electrical measuring equipment and is intended to be used as a measure of electrofluence of great importance.

In the known multi-digit resistivity measures, the quantization of the resistance is performed at the level of hundredths of an ohm, since the lever switches used in these measures, as a rule, are transient resistance of about 1-2 mΩ.

The aim of the invention is to expand the limits of reproducing large values, electrical conductivity (or small values of resistance, less than ohm) and ensuring multiple quantization thereof. This is achieved by connecting the four terminals of the first element to one current clamp: the winding of the magnetic compensator and the primary current of the magnetic current comparator, while one output of the current compensator amplifier is connected to the output end of the primary winding, and the second to the other current clamp the terminal of the resistor element, also connected to the output of the current comparator amplifier, the second output of which is connected to the adjustable secondary winding of the comparator connected to the input of the compensator winding.

The drawing shows a functional diagram of the device and the following conventions are adopted: / - exemplary four-clamping resistor element with conductivity G (resistance G), current terminals TI and 72 and potential HI and LV; 2 — magnetic single-winding current compensator with a core 3 of a magnetic state sensor, a winding 4 with the number of turns Wi and an amplifier 5; 6-magnetic comparator with a core 7 of a magnetic state sensor; an amplifier 8, a primary current winding 9 with a number of turns W and a secondary current winding 10 with a number of turns. connected through electromagnetic control devices of two controlled (dependent) amplifiers (current sources), one of which compensates with its output current / operating current of the measure /, and the second creates their shock / between the terminals P and P voltage and idling.

In accordance with Ohm’s law, reproducible

c (o

The compensator 2, which reacts to the difference in the currents (and /) flowing through the winding 4 and creates a magnetomotive force in the core 3, controls the amplifier 5 through the magnetic sensor of the core 3 so that the current (of this amplifier) compensates the operating current / in the winding 4 (and, accordingly, in the resistor element /), i.e. the sum of the indicated currents

/ + (- /) 0, (2)

i.e. ultimately ppm core 5 was zero.

Thus, the voltage drop between the potential transceivers P and P is created by the current / obtained from the output of the second controlled amplifier 8, namely:

f / t-G (3)

In turn, as a result of control by the comparator 6, the current / amplifier 8 is related to the operating current by the ratio

,(four)

 , 2 ,. h

from TV / ()

Vvs

After substitution of (3) and (4a) in (1), it is seen that the proposed conductivity is reproducible by the proposed measure

- “t

(five)

is greater than the initial conductivity G as many times as the number of turns of Wa winding 10 is greater than the number of turns of Wz Winding 9.

The proposed measure of electrical conductivity can be implemented both in the form of a multidischarge store of electrical conductivity, and in the form of a multidischarge store of electrical resistivity. Using as an element} - the storage of the initial conductivity the standard electrical resistance coils 10 are available; one; 0.1; 0.01; 0.0001;

0.00001 ohms on the basis of the proposed device, it is possible to create a series or one multi-range and universal store of electrical resistance - electrical conductivity for both large and small (up to thousand fractions of ampere) operating currents. If the operating current is very large, then as the windings 4 and P you can use a single wire-bar passed through the holes of the cores 3 to 7.

If the operating current is small, then the windings 4 9 can be performed with a sufficiently large number of turns Wi and Wz. If it is required that the scale of the proposed measure be in units of conductivity and be multi-digit, then the winding JO

with a variable number of input turns Ws according to the necessary code, it is also possible to change the number of input turns Wz of winding 9 (in some cases, winding 10 and 9 are swapped, i.e. switch

in the chain of measure), while the directions of the respective currents indicated in the drawing are preserved.

Subject invention

A measure of electrical conductivity, containing an exemplary four-clamping element with two current and two potential clamps, a magnetic compensator and a current comparator with

controllable amplifiers, characterized in that, in order to expand the range of producing large values of electrical conductivity (small resistance values) and ensuring its multiple quantization,

One current clamp of the four-clamping element is, therefore, connected: a winding of a compensator and a primary current of a magnetic current comparator, with one output of a current compensator amplifier

connected to the inlet end of the primary winding of it, and the second to the other current terminal cut the source element connected to the output of the current comparator amplifier, the second output of which is connected to the adjustable secondary winding of the comparator connected to the input of the compensator winding.

/ 7, f

r, - TC