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An open (single envelope) CFL [12] An encapsulated/closed (double envelope) CFL. Some fluorescent lamps emit ultraviolet radiation. [citation needed] The Health Protection Agency of the United Kingdom has conducted research concluding that exposure to open (single envelope) compact fluorescent lamps (CFLs) for over 1 hour per day at a distance of less than 30 cm can exceed guideline levels as ...
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor coating in the lamp glow.
Dimming fluorescent ballasts and dimming LED drivers often use 0–10 V control signals to control dimming functions. In many cases, the dimming range of the power supply or ballast is limited. If the light output can only be dimmed from 100% down to 10%, there must be a switch or relay available to kill power to the system and turn the light ...
More specialized equipment is needed to dim fluorescent, mercury-vapor, solid-state, and other arc lighting. Dimmers range in size from small units the size of domestic light switches to high-power units used in large theatrical or architectural lighting installations.
Circular and U-shaped lamps were devised to reduce the length of fluorescent light fixtures. The first fluorescent light bulb and fixture were displayed to the general public at the 1939 New York World's Fair. The spiral CFL was invented in 1976 by Edward E. Hammer, an engineer with General Electric, [7] in response to the 1973 oil crisis. [8]
Some emergency lighting manufacturers offer dimming solutions for common area emergency lighting to allow energy savings for building owners when unoccupied using embedded sensors. [4] Another popular method for lighting designers, architects and contractors are battery backup ballasts that install within or adjacent to existing lighting fixtures.
Similar to fluorescent lights, HMIs present problems with color temperature when used for film or video lighting applications.Unlike incandescent-lighting units, which are blackbody radiators limited to a theoretical maximum of 3680 K (the melting point of tungsten), HMI lamps, like all gas discharge lighting, emit the emission spectral lines of its constituent elements, specifically chosen so ...
The short-term flicker indicator P st LM is implemented in a light flickermeter which processes the light measured by means of a light sensor. The light flickermeter [ 14 ] [ 15 ] consists of four processing blocks which include weighting filters to account for frequency dependency of the visibility of TLMs as well as statistical processing to ...