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An early D'Arsonval galvanometer showing magnet and rotating coil. A galvanometer is an electromechanical measuring instrument for electric current.Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely.
Download QR code; Print/export Download as PDF; Printable version; In other projects ... Thermo galvanometer; V. Vibration galvanometer This page was ...
The first moving-pointer current-detecting device was the galvanometer in 1820. These were used to measure resistance and voltage by using a Wheatstone bridge, and comparing the unknown quantity to a reference voltage or resistance. While useful in the lab, the devices were very slow and impractical in the field.
Late 19th or early 20th century. This galvanometer was used at the transatlantic cable station, Halifax, NS, Canada Modern mirror galvanometer from Scanlab. A mirror galvanometer is an ammeter that indicates it has sensed an electric current by deflecting a light beam with a mirror. The beam of light projected on a scale acts as a long massless ...
The thermo-galvanometer designed by Mr W. Duddell can be used for the measurement of extremely small currents to a high degree of accuracy. It has practically no self-induction or capacity and can therefore be used on a circuit of any frequency (even up to 120,000~ per sec.) and currents as small as twenty micro-amperes can be readily measured ...
Action describes energy summed up over the time a process lasts (time integral over energy). Its dimension is the same as that of an angular momentum.. A phototube provides a voltage measurement which permits the calculation of the quantized action (Planck constant) of light.
A ballistic galvanometer is a type of sensitive galvanometer; commonly a mirror galvanometer. Unlike a current-measuring galvanometer, the moving part has a large moment of inertia, thus giving it a long oscillation period. It is really an integrator measuring the quantity of charge discharged through it. It can be either of the moving coil or ...
A vibration galvanometer is a type of mirror galvanometer, usually with a coil suspended in the gap of a magnet or with a permanent magnet suspended in the field of an electromagnet. The natural oscillation frequency of the moving parts is carefully tuned to a specific frequency; commonly 50 or 60 Hz. Higher frequencies up to 1 kHz are possible.