Why can a null measurement be more accurate than one using standard voltmeters and ammeters? What factors limit the accuracy of null measurements?

Why can a null measurement be more accurate than one using standard voltmeters and ammeters? What factors limit the accuracy of null measurements?

Question
Measurement
asked 2020-12-25
Why can a null measurement be more accurate than one using standard voltmeters and ammeters?
What factors limit the accuracy of null measurements?

Answers (1)

2020-12-26
Step 1
A null measurement be more accurate than one using standard voltmeters and ammeters because standard measurements of voltage and current alter circuits. There are numerical uncertainties in standard measurement of voltage and current. Current flow reduced by an ammeters and voltmeter draws more current.
In null measurement circuit does not alter. In null measurement voltage balance and no current passing through the measuring device.
Step 2
factors which are affects the null measurement:
-Resistance of wiring'
-Change in resistance due to change in temperature
-current sensitivity of measuring device.
0

Relevant Questions

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Previous studies show that \( \sigma_1 = 19 \).
For Englewood (a suburb of Denver), a random sample of \( n_2 = 12 \) winter days gave a sample mean pollution index of \( x_2 = 37 \).
Previous studies show that \( \sigma_2 = 13 \).
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