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In 1826, Poggendorff developed the mirror galvanometer, a device for detecting electric currents. He had an extraordinary memory, well stored with scientific knowledge, both modern and historical, a cool and impartial judgment, and a strong preference for facts as against theory of the speculative kind.
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 pointer. In 1826, Johann Christian Poggendorff developed the mirror galvanometer for detecting electric currents. The apparatus is also known as a spot ...
Mirror galvanometer by James W. Queen & Company Cascade above the Basin, Franconia Mountains, N.H, by James W. Queen & Company. James W. Queen & Company was an optical and scientific instrument company located at 924 Chestnut Street, Philadelphia, Pennsylvania, with a branch office in New York City, and active in various forms from 1853 to 1925, and subsequently as Gray Instrument Company ...
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.
The mirror galvanometer proved yet another point of contention. Whitehouse wanted to work the cable with a very different scheme, [43] driving it with a massive high-voltage induction coil producing several thousand volts, so enough current would be available to drive standard electromechanical printing telegraphs used on inland telegraphs. [44]
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Yolanda Saldívar, the woman who was convicted of Selena Quintanilla Pérez's murder, has filed for parole.. Thirty years after the death of the Mexican American singer, Saldívar, 63, filed a ...
Unlike the Phonofilm and Movietone systems in which the audio modulated the intensity of a recording lamp which exposed the soundtrack, thus creating a variable-density track, the GE system employed a fast-acting mirror galvanometer to create a variable-area soundtrack. A number of demonstrations of this system, now known as Photophone, were ...