How to use a universal bridge?

Last Update Time: 2019-01-05 11:33:24

(1) Measurement of resistance.

The measured resistor Rx is attached to the junction column.

First, the measured resistance is estimated, the selection switch and the range switch are placed in the appropriate position, the switch is placed in the "inner 1kHz", and the loss multiplier switch is independent of the resistance measurement. Adjust the sensitivity knob, reduce the sensitivity of the bridge, make the meter indication less than the full scale, adjust the two readings respectively, so that the meter is indicated to be zero. Then gradually increase the sensitivity of the bridge, and then adjust the two readings. When the sensitivity is maximum, the readout plate is adjusted to make the meter zero or close to zero. It shows that the bridge has reached the balance, notes the readings of the reading plate of the bridge, and according to the formula Rx= range switch indication value X,the results are obtained. The value of the measured resistor Rx.


For example, the range switch isplaced in 100Ω positions, the first reading disk is 0.8, the second bit reading disk is 0.055, and the measured resistance is Rx=100* (0.8+0.055) = 85.5Ω.


If the resistance size can not be estimated, the resistance can be attached to the "measured" junction column. The first reading disk is placed at "0", the second reading plate is placed at "0.05", the range is released for one stop, the adjustment sensitivity makes the meter pointer at about 50 A, and the selection switch is placed in "R> 10Ω"  or "R < 10Ω", turn the range switch, find the switch.


 The meter indicates the smallest gear, fixed in the gear, gradually increase the sensitivity of the bridge, adjust the second readings, make the meter minimum, so that the approximate value of the resistance can be measured, and then the appropriate range is selected according to the numerical value, and the accurate number is measured according to the measurement process of the above resistance.

 

(2) Measurement of capacitance.

The measured capacitor Cx is attached to the junction column, the switch is placed in the "inner 1kHz" position, the selection switch is placed in the "C" position, and the capacitance of the measured capacitance is estimated. The range switch is placed in the appropriate position, such as the 560pF capacitance, the range switch should be placed in the 1000pF gear, and the loss multiplier switch is placed in "DX0.01 (general capacitor). If it is a large electrolytic capacitor, it should be placed in "DX1", the loss balance switch is placed at "1", the loss adjustment knob is placed in "0", the sensitivity knob is adjusted to make the indicator less than the full scale, and the two reading plates of the bridge are adjusted first, then the loss balance is adjusted, the meter pointer is zero, and the sensitivity of the bridge is gradually increased, and repeatedly When adjusting the reading plate and loss balance of the bridge, the meter pointer refers to zero or close to zero when the sensitivity reaches the maximum. It is considered that the bridge has basically reached the balance, notes the readings of the bridge readings and the loss balance indicator, and according to the formula Cx= range switch readings X and the loss ratio of Dx= Switch value X loss balance indication value can be obtained capacitance and loss value.

 

For example: the range switch is 1000pF, the loss multiplier switch is placed at DX0.01, the first reading number of the bridge is 0.5, second readings of 0.025, the loss balance indication is 1.5,the capacitance Cx= 1000* (0. 5+0. 025) = 525pF; the capacitance loss Dx =0.01X1.5= 0.015.

 

(3)The measurement of inductance.

The measured inductor Lx is attached to the "measured" end, and the switch is placed in the "inner 1kHz" position, and the selection switch is placed in the "L" position, and the size of the inductor is estimated. Select the appropriate range, select the loss ratio switch position according to the inductor structure, the core inductor should be placed in the "QX 1" position, the core inductor should be placed in the "DX 1" position, the high Q inductance (such as the magnetic core inductor) should be placed in the "DX0.01" position, the loss balance knob is placed around "1", adjusting the sensitivity of the bridge to make the meter indicator less than full scale, first adjust the two reading plate, then adjust the loss balance, until the bridge sensitivity, to the maximum, the meter pointer to zero or close to zero, that is, the bridge basically reached balance. The readings of the reading plate of the bridge and the indication value of the loss balance are recorded.


According to the indication value of the formula Lx= range switch indication value X (first bit read disk value + second bit reading disk value) and the loss indicator value of the Qx= loss ratio (indicator X the inductance of the inductor) and the Q value of the inductor coil are calculated. For example : the range switch is 100 mH, the loss rate switch is " QX1 ", the first reading of the bridge is 0.8, and the second reading disk is 0.085, the loss balance indicator is 2.5, and Lx = 100 mHX ( 0.8 + 0.085 ) = 88.5 mH; qx = 1 x 2.5 = 2.5. If the loss rate switch is placed in the " DX1 " or " DX0.01 " position, the Q value is 1 / D.


This article is from Allicdata Electronics Limited.