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HALOGEN LAMP FAQS
1. What are the advantages of a halogen lamp?
2. How is a halogen lamp constructed?
3. How does a halogen lamp work?
4. Why is molybdenum foil used in a halogen lamp?
5. Are all halogen lamps dimmable?
6. Why is the halogen envelope made of quartz?
7. Does a halogen bulb have a longer life than a standard incandescent?
8. How do halogen lamps enable constant light output?
1. What are the advantages of a halogen lamp?
A halogen light source provides a crisp white light with excellent colour rendering, making it ideal for many applications. The use of halogen gas allows the bulb to burn for a longer period of time while maintaining light output.
BENEFITS OF HALOGEN LIGHT SOURCE:
- High quality light
- Long life
- High efficiency
- Constant lumen maintenance
2. How is a halogen lamp constructed?
A halogen lamp is an incandescent lamp with a tungsten filament contained within an inert gas and a small amount of halogen. The tungsten filament together with the halogen gas produces what is known as the halogen regenerative process, which allows the halogen lamp to operate at a higher temperature and with more efficiency than a standard incandescent lamp.
The construction of a halogen lamp is similar to that of an incandescent; however some differences can be noticed.
BELOW ARE THE MOST IMPORTANT ELEMENTS OF A HALOGEN LAMP.
- Gas: halogen gas usually bromine or iodine.
- Bulb: made of quartz to withstand high temperatures.
- Molybdenum Foil: used as a conductor to ensure the hermetic dealing of the lamp. It enables the filament to operate at higher temperatures.
3. How does a halogen lamp work?
Halogen lamps operate on the tungsten halogen regenerative principle which eliminates filament evaporation and bulb blackening. As a result, the initial lumens and colour temperature are maintained throughout the lamp life.
HERE’S HOW IT WORKS:
| 1. When a halogen lamp is turned on, tungsten particles evaporate from filament and attach on to bulb wall. At the same time, halogen is decomposed and becomes atomic halogen. |
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| 2. Atomic halogen is diffused on the bulb wall and combines with free tungsten particle to become transparent and volatile tungsten halide. |
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| 3. Due to the high temperature (over 500ºF) of the bulb wall, tungsten halide circulates back to filament. As the tungsten halide approaches the filament the tungsten and the halogen gas separate and the tungsten gets re-deposited on the filament. |
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| 4. As the tungsten get re-deposited on the filament, the halogen gas is released and ready to combine again, creating the halogen regenerative cycle process. |
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4. Why is molybdenum foil used in a halogen lamp?
Molybdenum foil is used as a conductor for halogen lamps, ensuring the hermetic sealing of the lamp.
5. Are all halogen lamps dimmable?
Halogen lamps are designed to operate at very high temperatures to ensure optimal performance. Dimming at above 60% of the rated volts can be done. Dimming below 60% of the rated volts can cause blackening and alter the tungsten halogen regenerative cycle process thus reducing brightness and lamp life. It is recommended to revert to full brightness for 1 minute prior to switching the lamps off.
6. Why is the halogen envelope made of quartz?
Due to the high operating temperature and pressure required to permit the halogen regenerative cycle process it is imperative that the envelope be extremely resistant to heat impact. Consequently, quartz glass is used as it is extremely durable and can withstand high temperatures.
7. Does a halogen bulb have a longer life than a standard incandescent?
Yes, typically halogen lamps last 2 to 5 times longer than traditional incandescent lamps. This is due to the halogen regenerative cycle process. The halogen gas helps the evaporated tungsten particles to deposit back on the filament instead of on the lamp wall. This postpones the breakage of the filament and allows the lamp to extend its life.
8. How do halogen lamps enable constant light output?
Halogen lamps are able to maintain constant light output over the life of the lamp since the tungsten particles get re-deposited on the filament instead of sticking to the lamp wall, therefore significantly reducing bulb blackening and maintaining light output.
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