Galvanometer

Galvanometer

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**How does it work**: an electromagnet is suspended between opposite poles of two permanent magnets. The electromagnet’s coil is attached to a pointer. When a current is in the electromagnet’s coil, a magnetic field is produced. This field interacts with the permanent magnet’s field, causing the loops of wire and the pointer to rotate. ===== **Daily use:** Most modern uses for the galvanometer mechanism are in positioning and control systems. A galvanometer mechanism is used for the head positioning servos in hard disk drive. They are also used in laser marking and projection. Galvanometer mechanisms are also used to position the pens in analog strip chart recorders such as used in electrocardiographs, electroencephalographs and polygraphs.