Definition of rheostat in English:



  • An electrical instrument used to control a current by varying the resistance.

    • ‘If your bathroom is bright, consider installing a rheostat (dimmer switch) or washing up by the light of a night light.’
    • ‘As the instruments darkened, I raised my tinted visor and turned up the rheostats.’
    • ‘She learned how to bend neon tubing into shapes and how to connect electrical circuits and insert rheostats and timers to provide special visual effects.’
    • ‘Liam recommends using a 15 watt bulb, mounted on the ceiling and connected through a rheostat, for making flash exposures, but in his correspondence with me has also noted that he had to recalibrate flash times when he changed bulbs.’
    • ‘When using a bright field microscope, adjust the light so that it is very dim by racking the condenser down, closing the diaphragm and keeping the rheostat at its lowest setting.’
    • ‘A rheostat, aka potentiometer or variable resistor is exactly that - a resistor that limits the current passing through it at a varying level - in this case, depending on the position of a rotating knob.’
    • ‘Noise is controlled by the optional rheostat, which does lower the noise.’
    • ‘The 80 mm fan is controlled either automatically based on your BIOS settings, or manually via a rheostat control on the rear of the unit.’
    • ‘An ideal situation would be a very bright bulb attached to a rheostat, so that the desired illumination level could be chosen as required.’
    • ‘These units were equipped with a cab signal system as well as a slow speed rheostat to control speed down to 2 ½ mph.’
    • ‘Perhaps a built-in rheostat could be a nice addition in a future revision.’
    • ‘Turn mixture to OFF and manual generator voltage switch rheostat to NORMAL.’
    • ‘Our maintainers determined recent rain, combined with chafed insulation on the wiring behind the formation-lights rheostat, had created a short circuit.’
    • ‘They often use a rheostat, which is similar to a humidistat, so that not only can you predetermine the level of humidity you want, but also allow the machine to adjust intelligently to overall humidity.’
    • ‘Indirect lighting with rheostat control was provided.’
    • ‘Researchers at the University of Pennsylvania School of Medicine have identified in normal cells that a common metabolic enzyme, which acts as a rheostat of cellular conditions, also controls cell replication.’
    • ‘And the by-wire throttle is not what we'd call micrometer-precise; it's much more an on/off switch than a rheostat.’
    • ‘The control panel consists of a sensitivity rheostat switch, an annunciator light, which also functions as a mute button to turn off the audible warning, and a green power-on light.’
    • ‘The light started to brighten as if turned by a rheostat.’
    • ‘We observed females from distances of 3-20 m with binoculars and a headlamp dimmed with a rheostat to the point where the female was just visible.’


Mid 19th century: from Greek rheos stream + -stat.