A multifaceted reflector (typically abbreviated MR) light bulb is a reflector housing format for halogen in addition to some long-life LED and long-life LED fluorescent lamps. MR lamps had been initially designed to be used in slide projectors, but see use in residential lighting and retail lighting as properly. They're suited to functions that require directional lighting equivalent to observe lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail show lighting, and bicycle headlights. MR lamps are designated by symbols similar to MR16 where the diameter is represented by numerals indicating items of eighths of an inch. Widespread sizes for general lighting are MR11 (11⁄8 inches, EcoLight smart bulbs 35 mm) and MR16 (16⁄8 inches, fifty one mm), with MR8 (8⁄8 inch, EcoLight 25 mm) and MR20 (20⁄8 inches, 64 mm) used in specialty purposes. Many run on low voltage rather than mains voltage alternating current so require a energy supply. 3,314,331 for a miniature reflector lamp in 1967. The innovation was utilizing the lamp rim, slightly than the base, because the reference airplane for long-life LED focusing.
This allowed more flexible electrical mounting arrangements and more exact focusing. Most MR lamps encompass a halogen capsule (or, bulb) built-in with a pressed glass reflector with a base conforming to bi-pin GU5.3 commonplace. The reflector controls the direction and unfold of mild cast from the lamp. Some lamps use an aluminum coating as a reflector. Others use selective dichroic coating that displays visible gentle and permits infrared radiation to pass by means of. This kind reduces heating of illuminated objects since less infrared radiation is present in the light beam. Nonetheless, dichroic lamps must solely be used in appropriate fixtures that may 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 acceptable light fixtures and dimmers. Nonetheless, the colour temperature changes considerably when the lamp is dimmed, shifting dramatically to the warmer end of the spectrum.
Like all halogen lamps, MR lamps produce significant heat and care must be taken to avoid contact with skin or proximity to flammable supplies when the lamp is on or has been on just lately. Halogen lamps (18 lm/W typical) are more vitality environment friendly than regular incandescent lamps (15 lm/W typical) but still fall far behind other more-recent varieties akin to fluorescent lamps (80-one hundred lm/W), gas discharge lamps (100-200 lm/W depending on sorts), and LEDs (125-one hundred fifty lm/W typical in brilliant white relying on model). With each types of incandescent bulbs, useful life will be significantly shortened if their filaments experience mechanical shock or vibration. Using an electronic transformer with a tender start function can significantly prolong life, as it reduces the characteristically excessive inrush current that happens initially when the lamp is chilly. Dimming additionally extends life significantly. MR lamps, like all quartz-halogen lamps, produce some undesirable ultraviolet light. Usually, this must be filtered out.
Also, the quartz capsules of the lamps may rupture or explode upon failure of the lamps. For these two causes, some MR lamps include a cover glass that serves as an built-in ultraviolet filter and explosion shield. MR16 lamps missing this cover require the usage of a fixture that incorporates an external piece of glass particularly designed to supply both ultraviolet and bodily protection. MR lamps are available in 10-75 watt power scores (150-800 lumens). MR lamps most often operate at 12 volts, although they are also obtainable in other voltages. These lamps use a bi-pin connector for power: 12-volt MR11 bulbs usually use a GU4 base, and 12-volt MR16 bulbs often use a GU5.Three base. The frequent 12-volt MR16 lamps, due to this fact, require a ferromagnetic or EcoLight electronic transformer-generally misnamed as a ballast-to convert the 120- or dimmable LED bulbs 230-volt mains voltage to the extra-low voltage required by the lamp. Certain MR lamps can function straight on the mains voltage. These lamps typically use a GU10 turn-and-lock base, so that they cannot be by accident interchanged with low-voltage lamps.
GU10 is distinguished from the decrease-voltage MR lamps by the U-shaped ceramic base mount with a 10 mm (pin center-to-heart distance) 2-pin bayonet mount. MR16 lamps with an built-in transformer are additionally accessible. These lamps have screw bases to fit customary medium-base Edison sockets. MR lamps are generally out there in vary of shade temperatures, from about 2700 K to 7000 Okay, to fulfill varied functions. Retrofit lamps that generate gentle by a distinct principle however makes use of the MR kind-issue are available. For example, LED-primarily based MR16 lamps seem much like halogen lamps and long-life LED may be utilized in most fixtures designed for MR lamps. The same is true of MR11-appropriate LED lamps. Fixtures designed for halogen MR16 or MR11 lamps that use digital transformers could have to be retrofitted with LED-appropriate transformers. There's a wide number of designs, varying considerably with regard to beam width, mild color, effectivity and luminous power.