What is a Halogen bulb?
   Halogen is a type of incandescent lamp. It has a tungsten filament just like a regular incandescent that you may use in your home, however the bulb is filled with halogen gas. When an incandescent lamp (one which produces light by heating a tungsten filament) operates, tungsten from the filament is evaporated into the gas of the bulb and deposited on the glass wall. The bulb "burns out" when enough tungsten has evaporated from the filament so that electricity can no longer be conducted across it. The halogen gas in a halogen lamp carries the evaporated tungsten particles back to the filament and re-deposits them. This gives the lamp a longer life than regular incandescent lamps and provides for a cleaner bulb wall for light to shine.

Why shouldn't I touch my halogen bulb with my fingers?
    Do not touch the surface of a quartz halogen bulb with bare fingers, as the quartz surface will be exposed to the salts and oils in the hand. This will cause a weak area and lead to premature lamp failure.  If you happen to contact the bulb with your fingers, carefully clean the quartz surface with a gentle solvent such as alcohol.
     Halogen MR-16 bulbs have a protective parabolic reflector housing, around the bulb itself.  This rule does not apply to the parabolic reflector or the front glass (when present).  The front glass (enclosed MR16 lamp) completely protects the halogen bulb from any possibility of contamination by touch.

Will dimming my halogen bulb extend it's life?
     The halogen cycle can be interrupted if the voltage and temperature of the lamp is operated too low. The result is lamp blackening. Lamp blackening and the consequent loss of lumens are standard for incandescent lamps, but halogen lamps are designed not to blacken as they age.  Halogen lamps maintain their lumen output throughout their lifetime due to the key mechanism of the halogen cycle which binds with the tungsten that is vaporized off of the lamp filament itself. Thus keeping the bulb walls clean. If lamp engineers could figure a way to get the tungsten to redeposit evenly back on the lamp filament, we could have a lamp that lasts forever. But, this is not the case, as the tungsten is redeposited on the coolest part of the filament (usually the ends of the filament), and consequently over time, the middle portion of the filament eventually thins, forming a weak spot, and eventually the filament breaks.
     The standard operating temperature of the bulb wall to maintain a halogen cycle is 250C.  When the temperature falls below this level the halogen cycle fails, and the lamp starts to act like a standard incandescent.  It is estimated that the cycle fails when a lamp is operated below 70-80% of its rated power.

Will dimming switches work with a halogen light bulb?
   Yes, conventional incandescent dimmers will work to dim halogen lamps. However, the effectiveness of the halogen cycle to keep the lamp walls clean and give longer life may well be affected. This cycle depends upon correct lamp operating temperatures, which of course will be changed when the lamp is dimmed. Therefore, using a dimmer may not extend the life of your halogen lamp as much as a dimmer typically extends the life of a standard incandescent lamp.
   The halogen lamp is designed to prevent the tungsten from depositing on the inside of the bulb wall and darkening it. Because the halogen action stops working when the bulb wall temperature falls below 260 degrees Centigrade, which may happen when the dimmer lowers the voltage, the halogen lamp blackens and its life is not prolonged as much as an incandescent lamp on a dimmer. Eventually a severely dimmed halogen lamp can become blackened and fail.
   The wall blackening can be partially reversed if the halogen lamp is operated at full power, non-dimmed, periodically to allow the halogen cycle to remove some of the deposited tungsten.

Why do halogen bulbs last longer?
   Hot-burning "halogen bulbs" can last two or three times longer than regular bulbs because they are filled with chemically active halogen gases that preserve the filament. The filament of an ordinary light bulb burns out because atoms of tungsten evaporate from its surface, so that it becomes thinner and thinner until it breaks. The evaporated tungsten is deposited on the inside surface of the bulb, where it forms a dark deposit. The gas inside a halogen bulb combines with the tungsten atoms that condense on the glass, removing the deposit. When the combined molecules touch the hot filament, the tungsten is redeposited there, and the gas is released to do the same trick again.
   A halogen bulb is often 10 to 20 percent more efficient than an ordinary incandescent bulb of similar voltage, wattage, and life expectancy. Halogen bulbs may also have two to three times as long a lifetime as ordinary bulbs, sometimes also with an improvement in efficiency of up to 10 percent. How much the lifetime and efficiency are improved depends largely on whether a premium fill gas (usually krypton, sometimes xenon) or argon is used.

Can a halogen lamp operate on AC and DC?
   Yes, the halogen lamp doesn't differentiate between whether the power source is AC or DC, as long as the potential is 120 Volts. However, when the lamp fails, the filament will break and may draw an arc. You need to fuse properly for this event.

When should I use an MR16 Halogen lamp with front glass?
   MR16 lamps without front glass should only be used in a closed fixture (fixture that keeps all parts of bulb enclosed) since the filament tube of all MR16 lamps is pressurized. In the unlikely event that the filament tube breaks, the closed fixture keeps glass particles from leaving the fixture. MR16 lamps with a built-on cover glass can be operated in an open fixture since the cover glass will contain any broken pieces of the filament tube.

What does "dichroic" mean?
   The term "dichroic" applies to MR16 lamps specifically, not in general to low-voltage halogen lighting. Dichroic describes the type of coating on the reflectors or front glass. These coatings can also be described as "multi-layer interference films". They are made up of dozens of layers of thin materials that have the unusual property of selectively reflecting or transmitting certain wavelengths of visible light, IR, and UV. Such dichroic coatings have been used since the 1960s to reduce the heat in the beam of certain reflector lamps. Many of our MR16 lamps have the combination of a halogen lamp and dichroic coated reflector, increasing lighting efficiency and providing clarity of color.  These lamps are specifically designed for use in display windows, shop and restaurant interiors. The coatings are also very durable and will not flake off or deteriorate as the lamp burns.

What is the difference between line voltage and low voltage?
   Line voltage in the United States is 120 volts. It is the voltage that is supplied to your home or office. Low voltage is less than the supplied voltage. Some lamps, like Halogen MR16's, run on low voltage. Getting low voltage to lamps requires that the supplied electricity (at 120 V) passes through a transformer to reduce it prior to operating the lamp.

What is the benefit of Halogen lamps over incandescent lamps?
   As a result of grain boundary etching and the development of porosity due to tungsten evaporation (near the end of life, a cross-section of the filament resembles Swiss cheese) within the filament, the resistance increases during life so the current decreases at constant volts. However, the current decrease is not substantial. Light output over life will depend upon both operating wattage and any bulb blackening caused by tungsten deposits on the bulb wall. The change in electrical resistance in halogen lamps is minimal because the tungsten halogen cycle replaces material in the filament and the higher gas pressure inside the bulb suppresses the evaporation of tungsten. This combined with the bulb cleaning cycle results in halogen lamps maintaining over 90% lumen output and wattage over life.

Do I need to recycle my halogen lamp?
   Halogen light bulbs are not recycled. Put used light bulbs in their original or new packaging and place in your regular waste removal container