#rheostat__variable_resistor  resistor for regulating current
  supertype:  resistor__resistance  an electrical device that resists the flow of electrical current
  subtype:  dimmer  a rheostat that varies the current through an electric light in order to control the level of illumination
  part:  wiper_arm__wiperarm__wiper__contact_arm__contactarm  contact consisting of a conducting arm that rotates over a series of fixed contacts and comes to rest on an outlet

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