A multifaceted reflector (typically abbreviated MR) mild bulb is a reflector housing format for halogen in addition to some LED and fluorescent lamps. MR lamps had been originally designed to be used in slide projectors, but see use in residential lighting and retail lighting as well. They are suited to functions that require directional lighting resembling monitor lighting, recessed ceiling lights, desk lamps, pendant fixtures, panorama lighting, retail display lighting, and bicycle headlights. MR lamps are designated by symbols comparable to MR16 the place the diameter is represented by numerals indicating units of eighths of an inch. Widespread sizes for common lighting are MR11 (11⁄8 inches, 35 mm) and MR16 (16⁄8 inches, 51 mm), with MR8 (8⁄8 inch, 25 mm) and MR20 (20⁄8 inches, 64 mm) used in specialty purposes. Many run on low voltage somewhat than mains voltage alternating current so require a energy provide. 3,314,331 for a miniature reflector lamp in 1967. The innovation was utilizing the lamp rim, fairly than the base, because the reference plane for focusing.
This allowed extra flexible electrical mounting arrangements and more exact focusing. Most MR lamps consist of a halogen capsule (or, bulb) built-in with a pressed glass reflector with a base conforming to bi-pin GU5.Three commonplace. The reflector controls the route and unfold of gentle forged from the lamp. Some lamps use an aluminum coating as a reflector. Others use selective dichroic coating that reflects visible light and permits infrared radiation to cross by way of. This kind reduces heating of illuminated objects since less infrared radiation is present in the light beam. Nevertheless, dichroic lamps must 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 could be adjusted when used with appropriate light fixtures and dimmers. However, the color EcoLight lighting temperature modifications significantly when the lamp is dimmed, shifting dramatically to the warmer finish of the spectrum.
Like all halogen lamps, MR lamps produce important heat and care should be taken to avoid contact with pores and skin or proximity to flammable materials when the lamp is on or has been on not too long ago. Halogen lamps (18 lm/W typical) are extra vitality environment friendly than common incandescent lamps (15 lm/W typical) however still fall far behind different more-latest types comparable to fluorescent lamps (80-a hundred lm/W), fuel discharge lamps (100-200 lm/W relying on sorts), and LEDs (125-a hundred and fifty lm/W typical in shiny white depending on type). With each varieties of incandescent bulbs, helpful life can be significantly shortened if their filaments expertise mechanical shock or vibration. Utilizing an electronic transformer with a smooth start function can significantly extend life, because it reduces the characteristically excessive inrush current that happens initially when the lamp is cold. Dimming additionally extends life considerably. MR lamps, like all quartz-halogen lamps, produce some undesirable ultraviolet mild. Usually, this have to be filtered out.
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Also, the quartz capsules of the lamps might rupture or explode upon failure of the lamps. For these two reasons, some MR lamps embrace a cowl glass that serves as an integrated ultraviolet filter and explosion shield. MR16 lamps lacking this cowl require using a fixture that incorporates an external piece of glass particularly designed to supply each ultraviolet and bodily safety. MR lamps can be found in 10-75 watt power ratings (150-800 lumens). MR lamps most often operate at 12 volts, though they are also available in different voltages. These lamps use a bi-pin connector for power: 12-volt MR11 bulbs usually use a GU4 base, and 12-volt MR16 bulbs usually use a GU5.3 base. The frequent 12-volt MR16 lamps, therefore, require a ferromagnetic or EcoLight 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 instantly on the mains voltage. These lamps sometimes use a GU10 flip-and-lock base, so they can't be by chance interchanged with low-voltage lamps.
GU10 is distinguished from the decrease-voltage MR lamps by the U-formed ceramic base mount with a 10 mm (pin center-to-center distance) 2-pin bayonet mount. MR16 lamps with an integrated transformer are additionally accessible. These lamps have screw bases to suit commonplace medium-base Edison sockets. MR lamps are commonly out there in range of coloration temperatures, from about 2700 Ok to 7000 K, to satisfy numerous applications. Retrofit lamps that generate light by a special principle but makes use of the MR type-factor are available. For instance, LED-primarily based MR16 lamps seem similar to halogen lamps and might be used in most fixtures designed for MR lamps. The identical is true of MR11-compatible EcoLight LED bulbs lamps. Fixtures designed for halogen MR16 or MR11 lamps that use digital transformers might must be retrofitted with LED-compatible transformers. There is a wide variety of designs, EcoLight LED bulbs varying significantly with regard to beam width, light color, effectivity and luminous power.