A multifaceted reflector (typically abbreviated MR) gentle bulb is a reflector housing format for halogen as well as some LED bulbs for home and fluorescent lamps. MR lamps have been originally designed for use in slide projectors, but see use in residential lighting and retail lighting as nicely. They are suited to purposes that require directional lighting reminiscent of observe lighting, recessed ceiling lights, desk lamps, pendant fixtures, panorama lighting, retail show lighting, and bicycle headlights. MR lamps are designated by symbols resembling MR16 where the diameter is represented by numerals indicating units of eighths of an inch. Frequent sizes for general lighting are MR11 (11⁄8 inches, 35 mm) and MR16 (16⁄8 inches, fifty one mm), with MR8 (8⁄8 inch, 25 mm) and MR20 (20⁄8 inches, sixty four mm) used in specialty functions. Many run on low voltage rather than mains voltage alternating current so require a power supply. 3,314,331 for a miniature reflector lamp in 1967. The innovation was using the lamp rim, somewhat than the base, because the reference airplane for focusing.
This allowed more flexible electrical mounting preparations and more precise focusing. Most MR lamps include a halogen capsule (or, bulb) integrated with a pressed glass reflector with a base conforming to bi-pin GU5.Three standard. The reflector controls the route and spread of mild forged from the lamp. Some lamps use an aluminum coating as a reflector. Others use selective dichroic coating that reflects seen mild and allows infrared radiation to go by. This sort reduces heating of illuminated objects since less infrared radiation is current in the light beam. Nonetheless, LED bulbs for home dichroic lamps should solely be used in compatible fixtures that can dissipate the heat. Dichroic lamps must not be fitted to recessed or enclosed luminaires with the IEC 60598 No Cool Beam image. The brightness of MR lamps might be adjusted when used with appropriate gentle fixtures and dimmers. However, the coloration temperature modifications considerably when the lamp is dimmed, shifting dramatically to the warmer finish of the spectrum.
Like all halogen lamps, MR lamps produce significant heat and care should be taken to keep away from contact with pores and skin or proximity to flammable materials when the lamp is on or has been on just lately. Halogen lamps (18 lm/W typical) are more power efficient than common incandescent lamps (15 lm/W typical) however still fall far behind different extra-recent types comparable to fluorescent lamps (80-a hundred lm/W), gas discharge lamps (100-200 lm/W relying on types), and LEDs (125-a hundred and fifty lm/W typical in vibrant white relying on style). With each sorts of incandescent bulbs, helpful life could be considerably shortened if their filaments expertise mechanical shock or vibration. Utilizing an electronic transformer with a comfortable start feature can considerably lengthen life, because it reduces the characteristically excessive inrush present that happens initially when the lamp is cold. Dimming additionally extends life considerably. MR lamps, like all quartz-halogen lamps, produce some undesirable ultraviolet gentle. Usually, this should be filtered out.
Also, the quartz capsules of the lamps may rupture or explode upon failure of the lamps. For these two reasons, some MR lamps include a cover glass that serves as an built-in ultraviolet filter and explosion shield. MR16 lamps missing this cover require using a fixture that incorporates an external piece of glass particularly designed to provide each ultraviolet and physical protection. MR lamps are available in 10-75 watt power ratings (150-800 lumens). MR lamps most often operate at 12 volts, though they are additionally obtainable in other voltages. These lamps use a bi-pin connector for energy: 12-volt MR11 bulbs often use a GU4 base, and 12-volt MR16 bulbs often use a GU5.Three base. The widespread 12-volt MR16 lamps, due to this fact, require a ferromagnetic or LED bulbs for home digital transformer-typically misnamed as a ballast-to convert the 120- or 230-volt mains voltage to the extra-low voltage required by the lamp. Sure MR lamps can operate directly on the mains voltage. These lamps usually use a GU10 flip-and-lock base, so that they cannot be unintentionally interchanged with low-voltage lamps.
GU10 is distinguished from the lower-voltage MR lamps by the U-shaped ceramic base mount with a 10 mm (pin center-to-middle distance) 2-pin bayonet mount. MR16 lamps with an built-in transformer are additionally available. These lamps have screw bases to suit standard medium-base Edison sockets. MR lamps are commonly out there in range of color temperatures, from about 2700 Ok to 7000 Okay, to fulfill varied purposes. Retrofit lamps that generate gentle by a special precept however makes use of the MR kind-issue can be found. For instance, LED-primarily based MR16 lamps appear much like halogen lamps and will be used in most fixtures designed for MR lamps. The same is true of MR11-suitable LED lamps. Fixtures designed for halogen MR16 or MR11 lamps that use digital transformers might must be retrofitted with LED-suitable transformers. There's a large number of designs, varying significantly with regard to beam width, light colour, efficiency and luminous power.