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thyristor

(Encyclopedia)thyristor, semiconductor switch used chiefly in power-control applications. Also called a silicon-controlled rectifier (SCR; see rectifier), it is a variation of the transistor. A thyristor is capable...

dog racing

(Encyclopedia)dog racing, trials of speed between dogs. Now contested on oval tracks, the sport developed from the ancient practice of coursing, in which specially trained dogs chase game animals in the open field....

Bradwardine, Thomas

(Encyclopedia)Bradwardine, Thomas brădˈwərdēn [key], c.1295–1349, English mathematician, natural philosopher, and theologian. He was chaplain to Edward III (c.1338) and later archbishop of Canterbury. As a ma...

Campbell, Sir Malcolm

(Encyclopedia)Campbell, Sir Malcolm, 1885–1949, English automobile and speedboat racer. A racing enthusiast from boyhood, Campbell set many speed records for motorcycles, airplanes, automobiles, and motorboats an...

night blindness

(Encyclopedia)night blindness, inability to see normally in subdued light. It is usually a result of vitamin A deficiency. The rod cells, one of two light-sensitive areas of the retina of the eye, are impaired in t...

railroad

(Encyclopedia)railroad or railway, form of transportation most commonly consisting of steel rails, called tracks, on which trains of freight cars, passenger cars, and other rolling stock are drawn by one locomotive...

Yiwu

(Encyclopedia)Yiwu, city (2010 est. pop. 1,200,000), central Zhejiang prov., E China. Although the city produces rice, oil crops, sugarcane, and manufactured goods (processed foods, textiles, and machinery), Yiwu i...

Saffir-Simpson scale

(Encyclopedia)Saffir-Simpson scale săfˈər– [key], standard scale for rating the severity of hurricanes as a measure of the damage they cause; it is based on observations of numerous North Atlantic Basin hurric...

Bedford, John of Lancaster, duke of

(Encyclopedia)Bedford, John of Lancaster, duke of, 1389–1435, English nobleman; third son of Henry IV of England and brother of Henry V. At the death (1422) of his brother and succession of his 9-month-old nephew...

York, Edmund of Langley, duke of

(Encyclopedia)York, Edmund of Langley, duke of, 1341–1402, fifth son of Edward III of England. He was made (1362) earl of Cambridge, served on expeditions to Spain and France, and married (1372) Isabel, daughter ...