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voltmeter

(Encyclopedia)voltmeter, instrument used to measure differences of electric potential, commonly called voltage, in volts or units that are multiples or fractions of volts. A voltmeter is usually combined with an am...

Schenectady

(Encyclopedia)Schenectady skənĕkˈtədē [key], city (1990 pop. 65,566), seat of Schenectady co., E central N.Y., on the Mohawk River and Erie Canal; founded 1661 by Arent Van Curler, inc. 1798. The General Elect...

Piazzolla, Ástor Pantaleón

(Encyclopedia)Piazzolla, Ástor Pantaleón, 1921–92, Argentinian composer and player of the bandoneón (a large accordionlike instrument), b. Mar del Plata. He spent much of his childhood in New York, returned (1...

piezoelectric effect

(Encyclopedia)piezoelectric effect pīēˌzōĭlĕkˈtrĭk [key], voltage produced between surfaces of a solid dielectric (nonconducting substance) when a mechanical stress is applied to it. A small current may be ...

Steinmetz, Charles Proteus

(Encyclopedia)Steinmetz, Charles Proteus stīnˈmĕts [key], 1865–1923, American electrical engineer, b. Breslau, Germany, studied at the Univ. of Breslau. Forced to flee Germany because of his socialist activiti...

Charters, Samuel Barclay

(Encyclopedia)Charters, Samuel Barclay, 1929–2015, American musical historian and author, b. Pittsburgh. In the 1950s he studied jazz and blues in New Orleans and traveled through the South, where he recorded neg...

fiber optics

(Encyclopedia)fiber optics, transmission of digitized messages or information by light pulses along hair-thin glass or plastic fibers. Each fiber is surrounded by a cladding having a high index of refractance so th...

graphite

(Encyclopedia)graphite grăfˈīt [key], an allotropic form of carbon, known also as plumbago and black lead. It is dark gray or black, crystalline (often in the form of slippery scales), greasy, and soft, with a m...

asphyxia

(Encyclopedia)asphyxia ăsfĭkˈsēə [key], deficiency of oxygen and excess of carbon dioxide in the blood and body tissues. Asphyxia, often referred to as suffocation, usually results from an interruption of brea...

Lenz's law

(Encyclopedia)Lenz's law, physical law, discovered by the German scientist H. F. E. Lenz in 1834, that states that the electromotive force (emf) induced in a conductor moving perpendicular to a magnetic field tends...