Fresnel spotlight

Fresnel spotlight

[frā′nel ′spät‚līt]
(electricity)
A lighting instrument that is composed of a lamp and a Fresnel (stepped planoconvex) lens; the unit can be made with or without reflectors and has a system to adjust the spacing between the lamp and the lens so as to control the light beam; models range from 100 to 5000 watts.
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