MR16

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Left to Right: GU10, standard MR16, MR11

MR16 (sometimes referred to as MR-16) is a standard format for halogenreflector lamps made by a variety of manufactures. MR16-compatible LED lamps are also available. MR16 lamps are regularly used in place of compact fluorescent lamps or standard incandescent light bulbs for applications including residential lighting and retail lighting. MR16 lamps were originally designed for use in slide projectors. They are well suited to a variety of applications that require directional lighting of low to medium intensity, such as track lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail display lighting and bicycle headlights.

Designation

MR16 is a coded designation in which MR stands for Multifaceted Reflector and 16 is the number of eighths of an inch the front is in diameter, in the case of MR16: 2 inches.

MR16-Compatible LED Lamps

LED MR11, 70 lm/W LED MR16

MR16-compatible LED lamps are also available. They are similar in shape to halogen MR16 lamps, and can be used in most fixtures designed for MR16 lamps. The same is true of MR11-compatible LED lamps.

Versions of the led lamps have been patented in the UK. Due to the low heat and power consumption they have been produced from plastic although this does not affect their efficiency. Their non-polarised AC/DC operation with current limitation over a wide voltage range 11.5 ~ 18 volts as a standard 12 volt version, allows a wide range of usage.

Quoted average rated life given by manufacturers is typically 30,000 - 50,000 hours depending on the product in question. This amounts on average to 1250 - 2080 days of continuous operation, or roughly three to six years.

Fixtures designed for halogen MR16 or MR11 lamps that use electronic power supplies may need to be retrofitted with "LED-compatible" power supplies. This is because these electronic power supplies require a minimum power lamp in order to function, and the LED lamps may be below this power. Fixtures that use magnetic transformers can generally be used with LED lamps without modification.

Products from some manufacturers incorporate full wave rectification so that either AC or DC can be used, whilst others require a DC supply and correct polarity must be observed.

At this time, there are few standards for MR16 and MR11 compatible LED lamps. As such there are a wide variety of designs of such LED lamps, varying significantly in beam control, light quality, efficiency and luminous power.

Unlike halogen MR16s, such lamps often do not have the multifaceted reflectors that give MR16s their precise beam control in a variety of beam spreads. Some rely on the optics of the LED(s) to control the beam. They may also have a simple cut-off apertures that limit beam spread. Others have individual reflectors for each LED.

As with other LED lamps available today, the quality and color temperature of the white light produced by such lamps varies. Many tend towards the blue end of the spectrum, being even "cooler" than fluorescent. Because of these variations, some MR16 and MR11 compatible LED lamps create significantly more natural looking light than others.

The least efficient of these lamps produce about 26 lm/W (lumens per watt), which is similar to the efficiency of halogen MR16s. The most efficient of these lamps available today produce about 70 lm/W, which exceeds the efficiency of compact fluorescent lamps.

In terms of total luminous power, such lamps range from being significantly less powerful than their halogen counterparts, to being comparable to the lower power halogen MR16s. The brightest available halogen MR16s are still significantly brighter than the brightest available LED versions.

Variations

MR16 lamps most often operate at 12 volts, although they are also available in other voltages. The common 12 volt MR16 lamps therefore require a magnetic or electronic transformer (sometimes misnamed as a ballast) to convert the 120 or 240 volt mains voltage to the operating voltage required by the lamp. Note that although halogen MR16 lamps can usually operate on either AC or DC voltage, LED devices require DC voltage and as such will require some kind of rectifier in the unit if AC is to be used.

Certain MR16 lamps can operate directly on the mains voltage. These lamps typically use a GU10 turn and lock base so they can't be accidentally interchanged with low voltage lamps. As such, they are often referred to as GU10 rather than MR16 lamps. Because of their use of much-finer wire, the filaments of lamps that operate directly from mains voltage are much more fragile than those used in low-voltage lamps.

Low-voltage MR16 lamps almost always have ANSI standard GU5.3 two-pin bases. MR16 lamps with an integrated transformer are also available. These lamps have screw bases to fit standard medium-base Edison sockets.

Smaller lamps are also manufactured in the less common MR11 and even less common MR8 formats, which have reflectors that are 1 3/8 inch (11/8" or 35 mm) and 1 inch (8/8" or 25 mm) in diameter, respectively. These smaller lamps appear very similar to MR16 lamps, also featuring similar multifaceted reflectors that are available in a variety of beam spreads. Their smaller size makes possible even smaller fixtures, but limits them to lower powers. MR11 and MR8 lamps have pins placed more closely together, preventing them from accidentally being interchanged with MR16 lamps.