A galvanometer is an instrument used to detect and measure small electric currents. It operates on the principle that a magnetic field interacts with a current-carrying coil, causing it to move. This movement is typically indicated by a needle on a dial, allowing users to read the current's strength. Galvanometers are essential in various applications, including electrical engineering, laboratory experiments, and educational demonstrations. They can also be found in devices like multimeters, which measure voltage and resistance in addition to current. Understanding how a galvanometer works is fundamental for studying electromagnetism and circuit theory.