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rheostat

(Encyclopedia)rheostat rēˈəstătˌ [key], device whose resistance to electric current depends on the position of some mechanical element or control in the device. Typically a rheostat consists of a resistance el...

Huntington's disease

(Encyclopedia)Huntington's disease, hereditary, acute disturbance of the central nervous system usually beginning in middle age and characterized by involuntary muscular movements and progressive intellectual deter...

servomechanism

(Encyclopedia)servomechanism, automatic device for the control of a large power output by means of a small power input or for maintaining correct operating conditions in a mechanism. It is a type of feedback contro...

ferry

(Encyclopedia)ferry, vessel providing passage over a river, lake, or other body of water for passengers, vehicles, or freight; the term is also applied to the place where the crossing is made and, by extension, to ...

furnace

(Encyclopedia)furnace, enclosed space for the burning of fuel. There are many kinds of furnaces, the type depending upon the fuel and the use to which the heat produced within it is put. Most familiar are the furna...

flywheel

(Encyclopedia)flywheel, heavy metal wheel attached to a drive shaft, having most of its weight concentrated at the circumference. Such a wheel resists changes in speed and helps steady the rotation of the shaft whe...

electrostatics

(Encyclopedia)electrostatics, study of phenomena associated with charged bodies at rest (see charge; electricity). A charged body has an excess of positive or negative charges, a condition usually brought about by ...

circuit breaker

(Encyclopedia)circuit breaker, electric device that, like a fuse, interrupts an electric current in a circuit when the current becomes too high. The advantage of a circuit breaker is that it can be reset after it h...

Rural Electrification Administration

(Encyclopedia)Rural Electrification Administration (REA), former agency of the U.S. Dept. of Agriculture charged with administering loan programs for electrification and telephone service in rural areas. The REA wa...

fan

(Encyclopedia)fan, device for agitating air or gases or moving them from one location to another. Mechanical fans with revolving blades are used for ventilation, in manufacturing, in winnowing grain, to remove dust...