SU1252739A1 - Digital meter of rlc-parameters - Google Patents

Abstract

This invention relates to the field of electrical lexunui. invention - improving the accuracy of measurements in a wide frequency range. Measuring instrument with i .-. IU parup 1 sinusoidal, for example, lil. G-lik 8;:. | 1L .iii1ykh elsme pssh and lrem impulse- H rf; A / D converter 1 h. Introduction of blocks 9 and 10 exemplary ii:, ix el meites, b forgings h It 7 image - n I l; x held by her, peg ek pinners 4 and 5, bipolar switch 1 i, amplifier 12, quad 13, pre - oOr; 1zop. 1 tel 16 frequencies, in code, three-liter buffers 15 m 17, register 18 commands, information display unit 2, microcomputer 19 and the formation of no-Bi IX in the meter provide the possibility of eliminating the influence of the parameters of amplifier 12 from - К L, С-parameters of semiconductor T1I X 1.pp -; Рптов in the frequency range with McUiiiM voltage level in WGH, that I ip their operability by-. 1 | p (chi: depts measurements. 2 ill. Ys NP NP ate IsD CO with 4.iJ.:; ". Jt

Description

The isobrege relates to electrical measuring equipment and can be used to measure the RLC parameters of circuits in a wide frequency range.

The purpose of the invention is to measure the accuracy of the components of the two-component complex impedance 16 and the fifth fixed contact of the switch 11. The movable contacts J and 71 are connected to the corresponding inputs of the amplifier 12, two outputs of which are connected to the corresponding inputs of the quad 13, two outputs connected to the inputs ADC 14. The output of the ADC 14 through the buffer 15 and the frequency converter in

SRI in the frequency range.

Figure 1 shows the functional tO code through a buffer 17 connected to the bus diagram of a digital RLC meter - not microprocessor data 20, to which, in addition, the input of the register 18 of commands and the data bus of RAM 21, the ROM 22 and the input of block 2 are connected 5 razheny information. The address bus of the RAM 21, the ROM 22 and the address inputs of the buffers 17 and 15, the command register 18 and the parameter display unit 2 are connected with the address bus of the microprocessor 20; 2 shows the replacement schemes for the object under investigation.

The device comprises a sinusoidal voltage generator 1; information display unit 2, measured impedance 3, first switch 4, second switch 5, first block 6 exemplary conductivities, second block 7 exemplary conductivities, first block 8 exemplary elements, second block 9 exemplary elements, third block 10 exemplary evil-1ents , two-pole switch 11, amplifier 12, quad 13, time-pulse analog-digital converter A1 SCH 14, second buffer 15, converter 16 frequency to code, first buffer 17, command register 18, micro-computer 19, microprocessor 20, operational remembers the RAM device 21, a read only memory ROM 22.

The sinusoidal voltage generator I is connected to the first input of the frequency converter 16 in the code, the first terminals of the first 6 and second 7 blocks of exemplary conductances, the first terminal of the measured impedance 3 and the first fixed contact of the switch II, the second fixed contact of which connected to the second terminal of the measured impedance 3 and the movable contact of the switch 5, the first fixed contact of which is connected with the first terminal of the first block of 8 exemplary elements, the second the terminal of the switch I1 connected to the third fixed contact and the first clip of the block 9 exemplary elements, to the second clip of which the fourth fixed contact of the switch 11 and the first pin of the block 10 about 55 a are connected, are respectively the additive and multiplicative components of its transmission coefficient. In the first cycle of tiled elements, the second terminal connected to the second output of the generator 1, the second input of the transducer eDeni contact 1 of the switch 11

the paddle 16 and the fifth fixed contact of the switch 11. The movable contacts J and 71 are connected to the corresponding inputs of the amplifier 12, two outputs of which are connected to the corresponding inputs of the quad 13, two outputs connected to the inputs of the ADC 14. The output of the ADC 14 via buffer 15 and the frequency converter into

formations. Control bus buffers 15 and 17, instruction register 18, RAM 21, ROM 22 and information display unit 2 are connected to the microprocessor control bus 20.

The second clamps of blocks 6 and 7 are exemplary: the conductivities are connected according to the first and third unsupported co-tacts of the switch 4, the moving contact of which

connected to the second fixed contact of the switch 5 and the connection of blocks 9 and 10 of the exemplary elements, while the second fixed contact of the switch 4 and the third fixed

contact switch} of the eye 5 are neutral, and eight outputs of the command register 1B are connected to the control inputs of the first 4 and second 5 switches, a two-pole switch

11, the first 6 and second 7 blocks of exemplary conductivities and the first 8, second 9 and third 10 blocks of exemplary elements.

RLC-parameter meter works

next way

In the initial state, the switch 4 is in the neutral position b, and the switch 5 is in the position a, In this position

is the measurement of the RLC parameters of sequential replacement schemes (Fig. 2a, b). Quad 13 has a view conversion function, a, -, and (t), where U (t) is its input voltage; but.

eDeni pin 1 switch 11

Nahol 1tc in position a, and contact 11 in position b The exemplary elements of blocks 8-10 in this cycle are active resistances

and r. The current in the generator circuit 5

i (t)

 R. + Z. + Z,

Ol

07

where Z, is the impedance of the measured resistance 3; - internal resistance (impedance) of the generator 1;

ten

extra

The input of the amplifier 12 receives the voltage U, (t) i (t) Zj. The output voltage of the quadrant 13 U (t) ag-t-a, K i (t) t2 in the ADC 14 is converted to the number of pulses

N ,,,, KU (t) Z, (4) and, (t) is its output voltage. five

Voltage U, (t) i, (t) Z, amplified, which is fixed in RAM 21. Codes are by amplifier 12 c) by the gain amplifier K and fed to the input of quadrant 3. Its output voltage is η (t) a + a , - K, U, (t) in A1Sh 14 20 with the conversion function (AF) of the form and (t) converts the voltage and „(t) into

NH bo - b, a „a, K uJ (t) 25 b b, a + a, -K. i, (t) Z, (2)

where X, y are respectively in-phase and quadrature components of impedance 30 b, bj are additive and multiplicative components of the transfer function ASCH 1 4. The N code is read by microcomputer 19 through buffer 15 and stored in 35 RAM 21.

In the second cycle, the measuring contact II of the switch 11 is converted to half C. Summarted istedans N (, N, and N) satisfy the system of equations

N ,, b, - b.a aX-i (t) (R -b-7cT); N ,, b, b, a „-аа, к 1 (0 (R + R ,,) +

 (five

p Lo-b, a ,, K i (t) f (“R.; b RO,)

 -ok

from which

R RO, iNn -NM) r (R ", 4rJ (N

07

- RoLlblL (Nj.7-ll4)

,,) - 2R (,,)

(6)

with Rn R .., R

01

07

R. -Nj. .) l, 74 2 2 (N ,, -N ,,) - (N ;; N ,,) J

resistance to Z and R,

equals 1

 (o,) - J-c- a squared impedance modulus

2 (o,) -.

2 U Voltage U ,, (t), K i | (t) Z

converted to A1SCH 14 in code

N .., ,, Vt) Z, (3)

which is fixed in the on-memory storage device 21 of the micro-computer 19.

In the measurement of capacitance C, the measured current impedance 3 and the exemplary elements of blocks 8 and 9 carry current i (t). In the first

In the third 1, measurement measurement, contact 1 1, the switch 11 is switched to the 55 measurement cycle, the switch 11 is in the j position. In this case, с с-1ary (П) is in position b, in impedance of resistance 3 and blocks of the 8th cycle - in position C, and in and 9 it is equal to the third - in position d. Stress

ten

The input of the amplifier 12 receives the voltage U, (t) i (t) Zj. The output voltage of the quadrant 13 U (t) ag-t-a, K i (t) t2 in the ADC 14 is converted to the number of pulses

which is fixed in RAM 21. Codes

N (, N, and N, satisfy the system of equations

N ,, b, - b.a aX-i (t) (R -b-7cT); N ,, b, b, a „-аа, к 1 (0 (R + R ,,) +

 (five

p Lo-b, a ,, K i (t) f (“R.; b RO,)

 -ok

which

RO, iNn -NM) r 2 (R ", 4rJ (N

07

- RoLlblL (Nj.7-ll4)

,,) - 2R (,,)

(6)

with Rn R .., R

01

07

R. -Nj. .) l, 74 2 2 (N ,, -N ,,) - (N ;; N ,,) J

Operation 7 is performed in the microcomputer 19, and the result of the calculations is proportional to the resistance value R of the two-component circuits.

When measuring the value of C or L, (Fig. 2 o, b), the exemplary capacitances C, C or Ii are used as model elements of blocks 8 and 9. LQ,, LO in the measurements in diagrams a and 6, respectively.

50

When measuring capacitance C, the measured current impedance 3 and the exemplary elements of blocks 8 and 9 carry current i (t). In the first

The measurement cycle switch 11 (P) is in position b, in the second cycle - in position C, and in the third - in position d. Stress

and „- ij (t) Z ,; U ,,. I, (t) Z; and „-i, (t) Z (8)

in amplifier 1 2, quad 13, A1D1 14 are converted into pulses

N.,., .K i; (t) (.- 4T); N ,, - 4 + b, .K .i; (t) (R 4

;(9)

N

,,) (R +

where Z, - R --J-- ,;

R

7 G. D

w () with ",

but . r-i- -e - -c -).

 0, oh

Solving a system of 9 equations for - we have for G Cf € „

1, -3N7.3N, i |

  S; -HG-2 7 J

 2G

rNei + Njj -2Nj 1

4N, J

(ten)

Woi God)

-02

and in

The operation of calculating (10) is in microcomputer 19.

If the measured two-pole device has the appearance of Figure 25, the active resistances KO are used as the elements of block 8, and the elements of blocks 9 and 10 are LO and LO inductance. In the first cycle, the switch 11 (II) is in position C, in the second cycle in position J, and in the third cycle in position e. Resistance Rj, unit 8 in the first cycle is equal to the sum of the internal resistances of the model inductances

LO, and RI.O ,. those. RO, in the second it is equal to R, the third is zero.

Then convertible squares of impedance modules

Z r

Zj R + 0 (L + bn,);

z R -t- Q (L L ,, LO),

(AND)

where R is R + RL, R, a, the corresponding codes recorded in RAM 21 satisfy the system of equations

N ,,,, K4 (t) (R b) H)} Nj, b, b ,, KU; (t) R

 Cj (L + C, f; (12)

,, K i (t) rR

OU 4, -b L,),

0

five

five

Lp Bd in mikiz which when Lg, ro-computer 19 by the formula

r) ,, 1. h 2 2 (N ,, N ,,) - (,,)

The inductance is determined.

The measurement of the RLC parameters of two-component-element elements with a parallel replacement circuit of FIG. 2B, 2) is carried out by measuring the conductivity of equivalent circuits and representing it through conductivities — synCC and quadrature G ,, i.e. . For the circuit of FIG. 2 in G

I „g

.

We

but for the scheme

FIG. 2-2 G,

1 „г 1 Р and Г - Р

In the current measurement cycle, switches 4 and 5 are in the & , the switch 1t (I) is in the position o, and 11 (11) is in the position B. The block 10 of exemplary elements is the active resistance R ,. In the measurement of Fig. 26, in the first cycle, the current i (t) of the generator I passes through Z ,, Z, resistance 3 and resistance Id of block 10. In the second cycle, switch 4 is switched to position 1 and parallel to resistance 3 the common-mode sample conductivity GOJ turns on.

In the third cycle, switch 4 is shifted to position C and, in parallel, KZy) 31 l is exemplary conductivity G

Because

P2

Z

2

GC G;

SL - - (Ge С „,) G.,

12527398

Since for the circuit (Fig. 28) G (OS, then

then find the difference 6, -G, 2Gf G, + G

01

can determine the value

27

G - Gj; - Gjf,

,

(lA)

In order to find G and G, in the first cycle Zjj is converted into a code of the number N "

N, - b, + b,, K i (t) Zj, (15)

and in the second cycle - in the code of the number N, NZ,, K4f (t) Z, (16)

In the third cycle, the switch 11 (|) is shifted to position 6, and the switch 1 1 () to position e. In this case, the voltage i, (t) RQ, reduced from the resistance R, is converted to the code N.

ten

The frequency f of the oscillations i (t) is converted by the frequency converter 16 into the code, and the result is entered by the micro-computer

19 through tristable 17. In

J

The case of the circuit of FIG. 2 2 G., G tog-C Lt

yes, given the values of G, G, and f, the inductance is determined from the expression

"five

I

2Tf

(24)

With exemplary measures of reactive conductivity, the process of measuring LC parameters is carried out as follows. Switch 4 is set to position c, and switch 5 is set to position b. Unit 7 exemplary conductivities represented, U L G / 17L is a set of exemplary conductors — NJ - b, b, ao + a, K i, (t) RoJ (17;

In the fourth cycle, switch 4 is switched to position b, and switch 5 to position C.

numbers

25 bridges. For the circuit of Figure 2B, the reference capacitance GO is connected in parallel to the capacitance C, and for the circuit of Figure 22, the sample inductance L is connected in the second measurement cycles. At the same time for

Here at the entrance of the RAM comes the code. about in -, n

30 of FIG. 26 block 10 exemplary

elements is an image- (18) price capacitance C, and for the circuit of Fig. 27, exemplary inductance LQ. In this case, equations 15 to 18 take the form

  .I-Ni. l „7. .7

NX

Bo, 0

Subtract, N, -N4 and, find the system of equations

Z

 N, - N4 7

  N; J e,.

+ G

to

(nineteen)

2 one

N, “b„ -kb, (, K i; (t) 7, v);

40

FROM WHICH WE DETERMINE THE IMPACT OF INPHASE1

Node component at G razheni (14) taking into account (19)

d -r from you-

45

N -, (, K4 (t) Zxp; (25) 1C -, ((t) z;); N4 - b „+ b, a„,

2 2 7

where) Co when analyzing the circuit of FIG. 2 & Z ZP CoLp for the circuit of FIG. From here

G:

 . “O) c, -4 - fEitH-.

so. .

and the value of R is

+ (G, +

(J

(23)

0

The frequency f of the oscillations i (t) is converted by the frequency converter 16 into the code, and the result is entered by the micro-computer

19 through tristable 17. In

J

The case of the circuit of FIG. 2 2 G., G tog-C Lt

yes, given the values of G, G, and f, the inductance is determined from the expression

"five

I

2Tf

(24)

With exemplary measures of reactive conductivity, the process of measuring LC parameters is carried out as follows. Switch 4 is set to position c, and switch 5 is set to position b. Unit 7 exemplary conductivities are presented

2 one

N, “b„ -kb, (, K i; (t) 7, v);

N -, (, K4 (t) Zxp; (25) 1C -, ((t) z;); N4 - b „+ b, a„,

2 2 7

where) Co when analyzing the circuit of FIG. 2 & Z ZP CoLp for the circuit of FIG. From here

G:

c, -4 - fEitH-.

+ (G, + G.,);

R

2R.

N, -N4 N, -N,

Nj-N, N, -N, Quadrature constituting wire 55

The value is from

G, - - cf,

a G.

y-y-y

2G "

Substitute the values of Gg, G and G,

we have

(22)

C rNi: N4 Ni; N.l -, -N, N, -N, J-

When determining inductance) L, then Gg

with L ,,

L "2L

one

N.-N4,

(27)

N, -N, N, -N, J

The codes of numbers N, N, N, N are stored in RAM 21 and processed in a microcomputer 19. The processing results are recorded in information display unit 2.

From expressions (7), (10), (13), (21), (26) and (27) it follows that the measurement result is invariant to the frequency f, the parameters b, b, ADC 14, vd, a, quad 13, the gain factor K amplifier.

Ensuring the possibility of eliminating the parameters of the amplifier 12 makes it possible to measure the RLC parameters of semiconductor elements in the frequency range with a low level of voltage on them, which ensures their operability after the measurements.

Claims (1)

Invention Formula A digital RLC parameter meter containing a sinusoidal voltage generator, a first block of model elements and a time-shifting analog-to-digital converter, so that, with increasing accuracy of measurement in Egypt frequency range. The second and third blocks of exemplary elements, two blocks of exemplary conductivities, nepBui i and second switches, two-pole switch, device, quad, frequency converter in code, command register, information display unit, two tristable buffer and a microcomputer comprising a microprocessor and random access read-only memory, and to a data bus the microprocessor has informational inputs of the command register of the information display unit, the operational and persistent storage data bus, as well as the information outputs of the first and second three-stable buffers; address addresses are connected to the microprocessor address bus Q 50 five 0 0 five The inputs of the first and second tristable buffer, the register of commands, the operational and permanent memory and the display unit are micro, and the control bus is micro. CPUs are connected to control buses of two tristable buffers, a command register, an operative and permanent memory of 1 pc devices and a display unit; blocks of exemplary conductivities, measured by the complex coaxial P1) of the first fixed contact of the two-pole switch, the second fixed contact of which go is connected to the second terminal of the measured complex resistance and a movable contact of the second switch, the first fixed contact of which is connected to the first pin of the first block of exemplary elements, the second clip connected to the third pin of the two-pole switch and the first clip of the second block of exemplary elements, the second pin of which is connected to) 1: 1: 5 pin the first switch, as well as the second contact of the second contact of the second switch, which is two pins: two: - a pole switch and the first ohm of the third block of exemplary elements, the second terminal connected to the second sinusoidal voltage gain code and five-pin power supply; the bottom-1 contact of the bottom: - L1Oo11osnogo switch, nepsbni and the second ground contact of which are connected to two inputs. amplifier, respectively two outputs of which are connected to the inputs of a quad- eagle, the output of which is connected to the input is the time of a pulse analog-digital preconditioner, the output bus of which is connected to the information input of the second buffer, the first and third fixed contacts of the first - The I o switch is connected to the second Mami terminals of the first and second blocks of exemplary conductivities, respectively, and the second is not connected: the first contact of the first switch and the third fixed contact of the second switch are neutral, while the eight outputs of the register of commands are connected to the first and second switches, a bipolar switch, two blocks of exemplary conductivities and three blocks of exemplary elements, respectively. Editor O. Bugir Compiled by V.Stukai Techred I.Veres Order 4619 / A7 Circulation 728 Subscription INSIGHTS of the USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. A / 5 Production and printing company, Uzhgorod, Projecto st., 4 FIG. 2 Proofreader V. But ha