SU1308967A1 - Method of calibration checking of self-balancing temperature-sensitive resistor bridges - Google Patents

Abstract

This invention relates to microwave radio technology and can be used to test self-balancing thermistor bridges. The aim of the invention is to improve the accuracy of verification. According to the proposed method, the determination of the actual power value is carried out in the operating mode of the device. For this, instead of working systems, the turn-off systems of which and the reference thermistors incorporate sources of constant voltage into the working shoulders of the working and supporting bridges. The method is applicable to those self-balancing bridges in which the auto-balance systems supply the working and supporting bridges with currents of different polarity. A device implementing the method comprises a working bridge 1, a supporting bridge 2, sources 3 and 4 of constant voltage. Voltmeter 5 measures the voltage at the working shoulder of working bridge 1, and voltmeter 6 measures the voltage difference between the voltage at working bridge 1 and the output voltage of the constant voltage source 7. The actual power value is calculated by the formula given in the specification. Compared with the prototype, the proposed method extends the functionality and provides the ability to automate measurements using digital voltmeters. 1 il. i SL оо о 00 with О5

Description

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This invention relates to radio engineering of the superhigh-frequency range, namely, to checking self-balancing thermistor bridges.

The purpose of the invention is to improve the accuracy of verification.

The determination of the actual power value is carried out in the operating mode of the device, for which instead of

booster and reference thermistors in the working head of the head, which allows

The shoulders of the working and support bridges include sources of constant voltage.

The drawing shows a device that implements the proposed method.

The device contains working 1 and supporting 2 bridges, the working shoulders of which include the first 3 and second 4 sources of constant voltage. A voltmeter 5 measures the voltage on the working bridge 1, and a voltmeter 6 measures the voltage between the voltages on the working bridge and the outputs of the constant voltage source 7.

The method is carried out as follows.

Balance bridges 1 and 2 and include autobalance systems. According to the indication of the voltmeter 6, the voltages on the working and supporting bridges are set to the same voltage as the third source 7 of the constant voltage using the sources 3 and 4 of the constant voltage. Changing the voltage of the source of constant voltage 3, establish the verifiable power value and record the readings of voltmeters 5 and 6, and the actual power value is calculated by the formula

2 +

and

K-R

de K p. real value of power Ui

and.

° ™ 545 wearing

voltmeter readings 5 |

voltmeter reading 6; the coefficient depending on the ratio of the shoulders of the working bridge (for an equal-shoulder 0 K 4);

the actual value of the working resistance of the thermistor.

Based on the calculated power value set by the installed DC voltage 3, the correct self-balancing thermistor bridge is working.

Form Sposo with the term definition of power that checks the second working and one with one in the water after the polarity, and the second wife, 35 working voltage stresses more than 40 and the spacing of the bridge quite

Ui - Uj - K Rd. K R "

The proposed method is applicable to those self-balancing bridges in which the autobalance systems supply the working and supporting bridges with currents of different polarities.

Using the proposed verification method provides the following advantages: the ability to test a thermistor bridge separately from the ter

.

not to take into account the error of equalization; the ability to test thermistor bridges at any values of the heating capacity of thermistors and at different grades of the scale, i.e. at any monitored power values.

Claims (1)

Claims The method of testing self-balancing thermistor bridges, including the determination of the actual power value, characterized in that, in order to improve the accuracy of the test, the first and second sources of constant voltage, respectively, are connected to the working shoulders of the working and supporting bridges, respectively, to the same output of the first source. The output of an additional third constant voltage source of the same polarity includes the autobalance system aI, changing the voltage of the first and second constant voltage sources set the voltage on the working and supporting bridges to the voltage of the third source, changing the voltage of the first source in the working arm of the working bridge, establish the verifiable power value, measure the voltage on the working bridge and the voltage difference between the working bridge and the third source voltage, calculate the actual value of power according to 2 and, and. and | K-R  Ui and. e Rd. actual power value; voltage on the working bridge; voltage difference between the working bridge and the third source of constant voltage, the coefficient depending on the ratio of the shoulders of the working bridge (for a K 4 equal-arm bridge);  the actual value of the thermistor operating resistance. K R "