Editing Galvanometer (section)

===Edward Weston===
[[File:D'Arsonval ammeter movement.jpg|thumb|320px|D'Arsonval/Weston galvanometer (ca. 1900). Part of the magnet's left [[pole piece]] is broken out to show the coil.]]
[[File:Weston galvanometer 6h440s49d 4j03cz922 dl full size.jpg|thumb|right|Weston galvanometer in portable case]]
[[Edward Weston (chemist)|Edward Weston]] extensively improved the design of the galvanometer. He substituted the fine wire suspension with a pivot and provided restoring torque and electrical connections{{Explanation needed|reason=electrical connections provided by springs??|date=September 2021}} through spiral springs rather than through the traditional wristwatch [[balance wheel]] hairspring. He developed a method of stabilizing the magnetic field of the permanent magnet, so the instrument would have consistent accuracy over time. He replaced the light beam and mirror with a knife-edge pointer that could be read directly. A mirror under the pointer, in the same plane as the scale, eliminated [[parallax]] observation error. To maintain the field strength, Weston's design used a very narrow circumferential slot through which the coil moved, with a minimal air-gap. This improved linearity of pointer deflection with respect to coil current. Finally, the coil was wound on a light-weight form made of conductive metal, which acted as a damper. By 1888, Edward Weston had patented and brought out a commercial form of this instrument, which became a standard electrical equipment component. It was known as a "portable" instrument because it was affected very little by mounting position or by transporting it from place to place. This design is almost universally used in moving-coil meters today.{{Citation needed|date=September 2021}}

Initially, laboratory instruments relying on the Earth's own magnetic field to provide restoring force for the pointer, galvanometers were developed into compact, rugged, sensitive portable instruments essential to the development of electro-technology.