Summarizing Null Measurements

Summary

• Null measurement techniques achieve greater accuracy by balancing a circuit so that no current flows through the measuring device.
• One such device, for determining voltage, is a potentiometer.
• Another null measurement device, for determining resistance, is the Wheatstone bridge.
• Other physical quantities can also be measured with null measurement techniques.

Glossary

null measurements

methods of measuring current and voltage more accurately by balancing the circuit so that no current flows through the measurement device

potentiometer

a null measurement device for measuring potentials (voltages)

ohmmeter

an instrument that applies a voltage to a resistance, measures the current, calculates the resistance using Ohm’s law, and provides a readout of this calculated resistance

bridge device

a device that forms a bridge between two branches of a circuit; some bridge devices are used to make null measurements in circuits

Wheatstone bridge

a null measurement device for calculating resistance by balancing potential drops in a circuit