A tangent galvanometer is an instrument used to measure small electric currents accurately. It consists of a coil of wire placed within a magnetic field, typically produced by a permanent magnet or electromagnet. When a current flows through the coil, it experiences a torque due to the interaction between the magnetic field and the magnetic moment of the coil. The coil rotates until the torque is balanced by the restoring torque provided by a suspension system, typically a suspension fiber. The angle of deflection of the coil is proportional to the strength of the current passing through it. By observing this deflection angle and using the tangent of the angle, the current can be accurately determined. Tangent galvanometers were widely used in the past for precise measurements of small currents and are still used in educational settings for teaching purposes.
