SU957127A1 - Dielectric loss factor meter - Google Patents

Description

(54) DIELECTRIC COEFFICIENT METER

LOSS

one

The invention relates to the field of studying the electrical relaxation characteristics of polymeric and other solid non-conductive materials, and more precisely to the measurement of their dielectric loss coefficient at various frequencies.

Known gauge dielectric loss, operating in stationary mode, made on the basis of the bridge method and cumeter 1.

The disadvantage of this meter is Q, which is longer than one measurement (especially when measuring in the range of low and infra-low frequencies), working at discrete frequencies.

A dielectric loss coefficient meter is also known, in which an electrical disturbance in the form of a DC voltage jump is applied to the test material at 15. The meter contains a measuring capacitor with the test material, connected through a switch to a DC voltage source and a reference resistor with an electrometer connected in parallel (2).

A disadvantage of the known dielectric loss meter is that for

In order to determine the dielectric loss coefficient, it is necessary to perform a series of mathematical operations that are called the “Homon Algorithm.

The algorithm is approximate; It can be used mainly for dielectrics having a wide relaxation spectrum in the frequency range above the relaxation frequency.

The aim of the invention is to increase the speed and accuracy of determining the dielectric loss coefficient.

The goal is achieved in that the dielectric loss coefficient meter contains a measuring capacitor with the test material, one plate of which is connected to the first output of the switch, the other facing to the first input of the electrometer directly and through an exemplary resistor with the second input of the electrometer and the ground bus, The second output of the switch is connected to one output of a constant voltage source, the other output of which is connected to the earth ground and the third output of the switch is entered a clock clock generator, a logarithmic clocking unit, a switch, scaling blocks, an adder, a dividing unit, the first output of a tunable clock pulse generator connected to one input of a logarithmic clocking unit, the output of which is connected to the control input of the switch, the last input is connected to the output of the electrometer, and the outputs through the scaling units - with the input of the adder, the output of which is connected to one of the inputs of the division unit, the other input of the latter is connected to the second output ohm tunable clock generator.

The drawing shows a functional diagram of the meter.

Dielectric loss coefficient meter contains measuring capacitor 1, in which sample 2 from test material is placed, switch 3, source 4 constant voltage, exemplary resistor 5, electrometer 6, tunable gayorator 7 clock pulses, block 8 logarithmic clocking, switch 9, maschtabuyushchie blocks 10-12, adder 13 and block 14 division.

Measuring dielectric loss coefficient works as follows.

A tunable generator of 7 clock pulses with an operating frequency fi, graduated in units of a circular frequency to determine the loss factor, produces clock pulses with a study period

 Tf)

which are fed to the input of block 8 logarithmic clocking. The cycle of operation of the logarithmic clocking unit 8 starts from the moment of switching the switch 3, it selects from the sequence of equal clock pulses that have a uniform distribution on a logarithmic time scale (at the base 2), i.e. implements the law of discretization.

After supplying a dc voltage to the test material with a switch 3 in a dielectric, a polarization process begins, causing a polarization current in (t) through the test material. The polarization current creates a voltage on the reference resistor 5

U (t) Rin {t) (2)

and enters the input of the electrometer 6, the output of which is equal to

Y (o. (3) RCU CU

The switch 9, which controls the unit 8 for clocking synchronization, switches the output of the electrometer to the corresponding inputs of the scaling units 10-12 at the moments of arrival of pulses.

in which the signals are multiplied by the corresponding scaling coefficients AI, chosen equal to:

with N 2

A 2 -0,600; And 2 -0,631; A4 -1.793; Ar -0,117; A4 -1.048; Av -6,213.

on Ai, signals from 10-10 scale are received on sum; summation occurs

 and

(four)

x (t) .Z AiY (ti) (- 0

The signal from adder 13 is fed to one input of dividing unit 14, to the other input of which clock frequency is supplied from a tunable generator of 7 clock pulses.

By introducing new elements into the meter of the loss factor — a tunable clock pulse generator, a logarithmic clocking device, a switch, scaling devices, an adder and a dividing device; ;

-operative automatic determination of dielectric loss coefficient at a given circular frequency without any additional calculations and tuning operations;

- the possibility of smoothly changing the circular frequency of determining the loss coefficient by changing the frequency of the tunable clock generator;

-increase the accuracy of determining the loss factor compared with the known device.

Claims (2)

1. Grokhalsky A.P. Goodness meters - cumeters. Novosibirsk, "Science, 1966. 2.Baird, M.E., Determination of dielectic behaviors, elt low freguencies from anomalais charging and discharging currents. - “Rew. Mod. Phys. V. 40, 1968, No. 1, p. 219-227