10.3.3—The use of a galvanometer in null methods

A galvanometer responds to small current and shows the null condition when its pointer is zero, indicating no potential difference across it.

Use the detector to locate balance rather than to carry substantial circuit current. Reverse connections if needed to identify which side is at higher potential.

Sliding a contact along a potentiometer wire until the galvanometer reads zero identifies the comparison length.

A zero reading does not mean no voltages exist elsewhere; it means the galvanometer’s own terminals have equal potential.