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New lighting systems have not used magnetic ballasts since the turn of the century, however some older installations still remain. Fluorescent lamps with magnetic ballasts flicker at a normally unnoticeable frequency of 100 or 120 Hz (twice of the utility frequency; the lamp is lit on both the positive and negative half-wave of a cycle).
This design uses a roof-mounted light collector, large-diameter optical fiber, and modified efficient fluorescent lighting fixtures that have transparent rods connected to the optical fiber cables. Essentially no electricity is needed for daytime natural interior lighting.
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.
The design of most analogue dimmers meant that the output of the dimmer was not directly proportional to the input. Instead, as the operator brought up a fader, the dimmer would dim slowly at first, then quickly in the middle, then slowly at the top. The shape of the curve resembled that of the third quarter of a sine wave.
The history of electric light is well documented, [11] and with the developments in lighting technology the profession of lighting developed alongside it. The development of high-efficiency, low-cost fluorescent lamps led to a reliance on electric light and a uniform blanket approach to lighting, but the energy crisis of the 1970s required more design consideration and reinvigorated the use of ...
The controlled lighting should scale its output so that at 10 V, the controlled light should be at 100% of its potential output, and at 0 V it should at 0% output (i.e., off). Dimming devices may be designed to respond in various patterns to the intermediate voltages, giving output curves that are linear for: voltage output, actual light output ...
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]
A GU24 lamp fitting is a bi-pin connector for compact fluorescent lamps (CFL) or LED lamps that uses a bayonet mount–like twist-lock bi-pin connector instead of the Edison screw fitting used on many CFLs, LED lamps and incandescent light bulbs. The design was initiated by the U.S. EPA and the Lighting Research Center in 2004, in order to ...