Tangent galvanometer
Electric current is often measured using an instrument called a tangent galvanometer. Able to measure the presence as well as the direction and power of currents, the instrument was first used in the early 1800s. It typically has a vertical copper wire coil, wrapped around a circular frame, and a compass in the middle. The compass needle generally responds to the magnetic field of the electrical current, which is compared to the Earths magnetic field in the experiment.
This scientific instrument has been built in many forms and more modern ones often use beams of light to determine measurements, while some versions are used to measure the magnetic field of the Earth The instrument works based on the tangent law of magnetism.
This principle defines the tangent of the angle, travelled through by the compass needle, as being proportionate to a ratio of how strong two magnetic fields are. These fields are usually perpendicular to one anCross-Curricular. Currents measured are typically proportional to the tangent of the same angle the needle goes through.
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