Instrument Accuracy: Does Error Remain % or Change to +-V?

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Discussion Overview

The discussion revolves around the accuracy of electromechanical instruments, specifically focusing on how error is represented at different scales of measurement. Participants explore whether the error remains a percentage of the reading or changes to a fixed voltage value as the measurement decreases from full scale deflection.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether the accuracy of a galvanometer, given as a percentage, translates to a fixed voltage error at lower readings, specifically asking if a 1% error at full scale deflection of 100V would still be ±1V at 50V, resulting in a ±2% error.
  • Another participant asserts that galvanometers are linear, suggesting that the 1% error should be consistent throughout its range.
  • A participant clarifies that they intended to refer to a voltmeter instead of a galvanometer.
  • One participant mentions that manufacturer specifications for tolerances should apply across the entire range of the instrument.

Areas of Agreement / Disagreement

Participants express differing views on how error is represented at lower readings, with some suggesting it remains a percentage and others indicating it may convert to a fixed voltage. The discussion does not reach a consensus.

Contextual Notes

There are assumptions regarding the linearity of the galvanometer and the applicability of manufacturer specifications that remain unaddressed. The implications of these assumptions on the error representation are not fully explored.

Who May Find This Useful

This discussion may be of interest to those involved in instrument calibration, electrical engineering, and anyone seeking to understand the nuances of measurement accuracy in electromechanical devices.

ineedmunchies
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If an electromechanical instrument's (say a galvanometer) accuracy is given as a percentage of its full scale deflection, what would its accuracy be at anything lower than full scale deflection?

My thoughts:
If say full scale deflection is 100V
The error is +-1% which is +-1V,
Does that mean at a reading of 50V it would still be +-1V which would be be +-2%?

Or does it remain as a percentage error, and the error would be +-0.5 V at +-1% still?
 
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Galvanometers are linear so expect 1% error throughout its range.
 
Sorry i meant to type voltmeter in there.
 
If the tolerances are given by the manufactures, that should be valid throughout its range.
 

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