A multifaceted reflector (usually abbreviated MR) light bulb is a reflector housing format for halogen in addition to some LED and fluorescent lamps. MR lamps were originally designed to be used in slide projectors, but see use in residential lighting and retail lighting as properly. They're suited to purposes that require directional lighting comparable to track lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail display lighting, and bicycle headlights. MR lamps are designated by symbols similar to MR16 the place the diameter is represented by numerals indicating models of eighths of an inch. Widespread sizes for normal EcoLight lighting are MR11 (11⁄8 inches, 35 mm) and EcoLight MR16 (16⁄8 inches, fifty one mm), with MR8 (8⁄8 inch, 25 mm) and MR20 (20⁄8 inches, 64 mm) utilized in specialty applications. Many run on low voltage moderately 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, rather than the bottom, because the reference airplane for focusing.
This allowed extra flexible electrical mounting preparations and extra exact focusing. Most MR lamps consist of a halogen capsule (or, bulb) integrated with a pressed glass reflector with a base conforming to bi-pin GU5.3 customary. The reflector controls the path and spread of mild cast from the lamp. Some lamps use an aluminum coating as a reflector. Others use selective dichroic coating that displays seen gentle and permits infrared radiation to pass via. This kind reduces heating of illuminated objects since much less infrared radiation is current in the sunshine beam. Nonetheless, dichroic lamps must only be used in compatible fixtures that may dissipate the heat. Dichroic lamps should not be fitted to recessed or enclosed luminaires with the IEC 60598 No Cool Beam symbol. The brightness of MR lamps will be adjusted when used with acceptable light fixtures and dimmers. However, the color temperature changes significantly when the lamp is dimmed, shifting dramatically to the hotter finish of the spectrum.
Like all halogen lamps, MR lamps produce significant heat and care must be taken to keep away from contact with 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 more energy efficient than common incandescent lamps (15 lm/W typical) but still fall far behind different extra-latest types such as fluorescent lamps (80-a hundred lm/W), gas discharge lamps (100-200 lm/W depending on sorts), and LEDs (125-one hundred fifty lm/W typical in shiny white relying on type). With each kinds of incandescent bulbs, helpful life can be considerably shortened if their filaments expertise mechanical shock or vibration. Utilizing an electronic transformer with a smooth start function can considerably lengthen life, because it reduces the characteristically excessive inrush current that occurs initially when the lamp is cold. Dimming additionally extends life considerably. MR lamps, like all quartz-halogen lamps, produce some undesirable ultraviolet gentle. Often, this have to be filtered out.
Additionally, the quartz capsules of the lamps might rupture or EcoLight explode upon failure of the lamps. For these two causes, some MR lamps include a cowl glass that serves as an integrated ultraviolet filter and explosion shield. MR16 lamps lacking this cover require the usage of a fixture that incorporates an external piece of glass particularly designed to provide each ultraviolet and physical protection. MR lamps are available in 10-seventy five watt power rankings (150-800 lumens). MR lamps most frequently function at 12 volts, though they're additionally obtainable in different voltages. These lamps use a bi-pin connector for energy: 12-volt MR11 bulbs often 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 electronic transformer-typically misnamed as a ballast-to convert the 120- or 230-volt mains voltage to the extra-low voltage required by the lamp. Certain MR lamps can function directly on the mains voltage. These lamps sometimes use a GU10 turn-and-lock base, so they cannot be by chance 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 heart-to-heart distance) 2-pin bayonet mount. MR16 lamps with an integrated transformer are additionally available. These lamps have screw bases to suit commonplace medium-base Edison sockets. MR lamps are generally obtainable in vary of shade temperatures, from about 2700 Okay to 7000 Ok, to fulfill varied applications. Retrofit lamps that generate gentle by a unique principle however uses the MR form-issue can be found. For example, LED-based mostly 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 LED lamps. Fixtures designed for halogen MR16 or MR11 lamps that use digital transformers may have to be retrofitted with LED-suitable transformers. There's a large variety of designs, varying considerably with regard to beam width, mild colour, efficiency and luminous power.