A galvanometer detects and measures very small electric currents:

Commonly used in devices like bridges and potentiometers to show zero current (null deflection)
It works by passing current through a coil placed in a magnetic field
The current creates a magnetic force, causing the coil to rotate
This rotation moves a pointer across a scale, showing the current’s presence and direction
The amount of deflection depends on the strength of the current flowing through the coil