SU690409A1 - Arrangement for measuring parameters of two-pole, their ratio and relative deviation from nominal rating and standard value - Google Patents

Description

(54) DEVICE FOR MEASURING THE PARAMETERS OF TWO-BOLSHEARS, THEIR RELATIONSHIPS AND RELATIVE .DISCONNECTION FROM NOMINAL AND SAMPLE VALUES

the reference two-pole and the movable contact of the switch is connected to the input of the parameter converter, the output of which is through the control 1 the 1st converter is connected to one of the inputs of the comparator: the other input of which is connected to the output of the reference voltage source, and the output of the comparator is connected to the input of the control unit the first output of which is connected via a compensating voltage source to the control input of the controlled converter, the second output of the control unit is connected to the input of the mode setting unit, and the third output b the control loop is connected to the control input of the switch.

The drawing shows a block diagram of a device comprising a controlled converter 1, a comparator 2, a source of reference voltage 3, a control unit 4, a source of a compensating voltage 5 (for example, stepped or linearly variable), a parameter converter 6, a switch 7, a task block mode 8, measurable and exemplary two-terminal 9 and 10, respectively.

Consider the operation of the device when bipolar 9 and 10 are resistors.

In the initial state, the switch 7 is in the position shown in the drawing. The block 8 sets the required mode to the device 10, the converter of the parameter b converts the value of the parameter of the resistor 10 into an electrical voltage of the proper value. The signals at the output of the controlled converter 1оИ at the output of the source of the compensating voltage 5 are absent. The input of the comparator 2 receives the voltage U from the source of the reference voltage.

I. Measurement of resistance.

Let resistor 10 be surplus, and resistor 9 be a measurable resistance.

Before each measurement of the resistance value, the calibration of the transducer of parameter 6 and the controlled transducer 1 is performed. The calibration is as follows. In response to a command coming from control unit 4 to block 8, the latter produces the necessary voltage, which is supplied to resistor 10. At the same time, a command from the control unit is fed to the input of the source Nick compensating voltage 5. Compensating voltage is fed smoothly or discretely to the control input controlled converter 1. Converter 1, under the action of voltage received from source 5, changes its gain. The input of controlled converter 1 receives the voltage from the output of converter b, which is directly proportional to the resistance value of resistor 10. At the output of controlled converter 1, the voltage changes smoothly or discretely until it is equal to the reference signal UQ. In case of equality of input voltages, the comparator generates a signal that is fed to the input of the control unit 4. In the case of compared voltages, the mathematical expression takes the form;

(one)

RO-N, -

PO - resistance 10;

where k is the transfer coefficient

parameter converter 6;

kj is the gain of the controlled transducer.

After the signal is received from the comparator, the control unit 4 generates a control potential, which is fed to the input of the source of the compensating voltage 5. The voltage value is last memorized, which serves to fulfill the condition (1). This completes the calibration.

Further, at the command received from the output of the control unit, the switch

7 connects test resistance 9 to the converter input. At the device output 11, a voltage will act

Ue ,,,. K, .k2-, (2) where is the test resistance

Equation (2) can be rewritten in view of (1) in the form:

and .R. s) (KX jj

Equations (3) U and IP ,, are constant values. The output voltage of the device is directly proportional to Ry. Equation (3) shows that temporal and temperature changes of K, and Kj do not affect the result.

. Ry measurements.

P. Measurement of the ratio of resistance.

The initial state of the device is the same as in the previous example. A resistor 10 is connected to the input of the parameter converter b.

According to the command received from the control unit 4, the source of the compensating voltage 5 delivers the variable signal to the control input of the controlled converter 1, changing its transmission coefficient to off-stroke. This means that the comparator generates a signal arriving at the control unit 4. The control unit generates a command that is sent to the input of the compensating voltage source and to the input of the switch.

In the source of the compensating voltage, the favorable voltage is remembered, and the switch 7 connects a resistor 9 to the input of the converter 6. At the output 11 of the device there will be a voltage

„LJebw Srth where h - resistance 9.

This equation can be rewritten in view of (1): p

 guas

Consequently, the output of the device will be a voltage, whose value is proportional to the ratio

since 1 / const

W. Determination of the relative deviation of resistance from the model.

The initial state of the circuit is the same as in the first example. The operation of the device is similar to the first two cases.

According to the instruction received from control unit 4, the circuit is balanced. At this moment equality (1) will be true.

Then the switch connects a resistor 9 to the input of the parameter 6 transducer. At the same time, there will be a voltage between the output of the device 11 and 12

ive ". (o-.)

(4) In view of (1) the equation

(4) takes the form:

From the obtained equality it can be seen that the device measures the relative deviation of the measured resistance from the reference one.

1U. Determination of the relative deviation of the measured resistance.

The initial state of the circuit is similar to the first case. As before, the device is initially calibrated to achieve performance, equality (1).

After calibration, the switch, unlike the previous three cases, does not switch to another position. For the time of measuring the deviation of the resistance from its original value, the source of compensation is always voltage 5 stores its output voltage. Let the value of the resistance of the Poison during this time changed by the value of dT, then between the outputs 11 and 12 of the device there will be a voltage

d1G. (- ID-.dtg). k, (5) In view of (1). k,. kj equation (5) takes the form:

AV-45-Vo o

From the obtained equality it can be seen that the voltage increment is proportional to the relative deviation of the resistance from its initial value.

The principle of operation of the device was considered on the example of measuring the resistance of resistors. However, the device can also be used to measure the parameters of other radio elements - capacitors, semiconductor diodes, transistors, etc.

Claims (2)

1. USSR author's certificate No. 444855, cl. H 01 C 17/00, 1975. 2. Authors certificate of USSR / 411377, cl. G 01 R 17/06, 1975 (prototype).  . -. : wiS5i: -:.  -, -i.r-y