A potentiometer is considered a null-type instrument because at balance it?

  • ADraws essentially no current from the source being measured through the detector branch
  • BAlways draws maximum current
  • CUses no reference voltage
  • DMeasures only resistance
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Correct Answer: A. Draws essentially no current from the source being measured through the detector branch
Explanation: At null balance there is no detector current, enabling accurate comparison without loading the measured source in the ideal case.
Reference: Standard measurements and instrumentation: potentiometers