SU1594449A1 - Meter of parameters of capacitors - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used to automatically measure the parameters of capacitors, represented by a parallel two-element replacement circuit. The purpose of the invention is to improve the accuracy of measuring the parameters of capacitors. The meter consists of computing unit 1, differential amplifier limiter 2, integrator 3, discretely controlled resistance 4, analog inverter 5, generator 6 clock pulses, switch 7, frequency divider 8, reversible counter 9, block 10 comparison of time intervals. The control object is a parameter-voltage converter 11, consisting of equivalent resistances 12 and a capacitance 13 of the control object, a resistor 14, an operational amplifier 15. In the invention, an increase in accuracy is achieved by introducing a definition of the moment of information retrieval by time ratios obtained by encoding the period directly output the clipped signal of the differential amplifier limiter 2, and the parameter-to-voltage converter output conversion is eliminated; and and integration with their attendant inaccuracies in E. 2 Il.

Description

2 CxRoRi

Given vfazheny for T floor

Ri -R.

p x

RT + R

A signal of the square wave type from the output of the limiting amplifier 2 is fed to one of the inputs of the time interval comparison unit 10 in which the pulse number code of the period value T is formed (or a multiple of the time interval). The pulses of the reference frequency f from the oscillator 6 of the clock pulses through the switch 7, which is in position I, are fed to the input of the time comparison unit 10, in which the code n, fj-T is fixed. Upon completion of the coding T, the control signal of the block 10 switches the switch 7. The input of the block 10 is supplied with clock pulses of frequency f | j / N, where N is the division factor of the frequency divider 8, arbitrary, beforehand given positive number (Nf l). In block 10, form T

Routes code n; At the output of block 10, which controls the reversible counter 9, pulses appear, the number of which is proportional to the difference of the codes (n j-n). This number is recorded in counter 9, the signals from the outputs of which switch the resistance of the dis-. implicitly controlled resistance 4, as a result of which the oscillation period in the circuit and, accordingly, the code n, fixed in block 10, change.

25 2CxRoRj

or

N2CiRi R R; -RO

 h

R; -R /

Rj ro

otschtsa

hg x

Ro 4R4 (1-N) 5R4TT-N) + NR

35

For example, with N 2

p - 15lRj

- 4R4-2R

Substitute this value for T., we get

0

.Tj. -RjzRo2p tg

 ilJ

 naR

RoRjf 2l.

I.

25

/

45

so

Codes n, and n jft (or n j, n J, Hj), corresponding to TC and R, are fed to computational unit 11, where the value is calculated.

The value of R can be calculated by the formula (when)

RxRoRjj

 jR () - 2ReR4

 where is r,

const.

55

Formula

the invention

A capacitor parameter meter containing a parameter-voltage converter, differential

limiting amplifier, integrator, discrete controlled resistance analog inverter, clock generator, switch, frequency divider, reversible counter, 5yok comparison of time intervals, with the output of the differential limiting amplifier connected to inputs). integrator, the output of which is connected to the inverti-circular input of the differential limiting amplifier, with the first output of the device and with the analog; discrete controllable input; resistances, whose control inputs are connected to the corresponding; reversible counter outputs, and; output with the second The OUTPUT of the device, whose input through an analog inverter is connected to a non-inverting input of a differential amplifier -: limiter, output of a frequency divider: connected to the first input of a cIvIntZ Y5 unit.

rrt / 6.

IIIIHillllll

intervals, the first and

The second outputs of which are connected respectively to the summing and subtracting inputs of the reversible counter, differing from the fact that, in order to improve the measurement accuracy, a computing unit was introduced, the first and second inputs of which are connected respectively to the code outputs of the reversible counter and the outputs of the time interval comparison unit, the second input of which is connected to the output of the differential limiting amplifier, the third output - to the control input of the switch, the first output of which is connected to the input frequency divider, the second output - with output of divider

frequencies, and the input is with the output of the clock generator, the output of the computing unit is connected to the output of the measurement result of the device.

NT, .H /.

Claims (1)

Claim Capacitor parameter meter, containing a voltage-differential parameter converter 7 1594449 eight amplifier-limiter, integrator, discrete controlled resistance ,; analog inverter, clock pulse generator, switch, frequency divider, reversible counter, time interval comparison unit, with the output of the differential amplifier-limiter connected to the input. integrator, the output of which is connected to the inverting input of the differential limiting amplifier, to the first output of the device and to the analog input of a discrete controlled resistance, the control inputs of which are connected to the corresponding outputs of the reversible counter, and the output to the second output of the device An analog inverter is connected to a non-inverting input of a ₂ 0 delimiter differential amplifier, the output of the frequency divider is • connected to the first input of the time interval comparison block, the first and The second outputs of which are connected respectively to the summing and subtracting inputs of the reversible counter, characterized in that, in order to improve the measurement accuracy, a computing unit is entered in it, the first and second inputs of which are connected respectively to the code outputs of the reversing counter time, the second input of which is connected to the output of the differential amplifier-limiter, the third output - to the control input of the switch, the first output of which is connected to the input divides A frequency of the second output - with an output of the frequency divider, and an input - output from said clock pulse generator output computing unit connected to the output "Measurement Result" device. FIG. 2