• Like the incandescent lamp the halogen lamp produces light when a length of wire is heated

• With an incandescent lamp tungsten particles burn off the filament and are deposited on the inside surface of the bulb

• With halogen lamps tungsten particles combine with the halogen gas and deposit themselves back onto the filament. This is known as the Halogen Cycle

• The filament is continually being rejuvenated and lasts much longer " up to ten times more than a standard incandescent lamp filament

• Certain tungsten halogen lamps are also referred to as quartz halogen or quartz iodine lamps, where the bulb containing the filament is quartz glass

Halogen Dichroic Lamps

• Halogen lamp capsule with an integrated dichroic reflector

• Dichroic means glass coated with microscopic layers of metallic oxides which transmit heat and reflect light

• This integrated lamp design is referred to as an "MR16 which means Miniature Reflector, 16 eighths of an inch in diameter

• MR11 types are smaller at 11 eighths of an inch in diameter

• A glass cover on the front of the lamp provides protection from ultra violet (UV) radiation

G9 and GU10 Halogen Lamps

G9

• Mains voltage, small (51mm) halogen capsule lamp with G9 base

• Integral UV filter and dimmable

GU10

• Mains voltage, aluminium reflector quartz halogen lamp with GU10 base

• Similar in appearance to a low voltage halogen dichroic lamp

• Integral UV filter and dimmable

Strengths

• Instant on

• Instant full light output

• Whiter light than incandescent

• Excellent colour rendering

• Longer life

• Compact size for designer type fittings

• Dimmabl

Weaknesses

• Certain types require a transformer - adding cost

• Heat generated

• Care required with quartz glass

• Higher cost of lamp