What is the difference between standard bulbs, vacuum bulbs, krypton bulbs and halogen bulbs?
Small bulbs for flashlights and bicycle lights are typically vacuum filled (that is, they are not filled). Krypton bulbs are an inert gas fill with krypton, argon or xenon as a component, which allows a higher light output. Halogen bulbs use a fill with a halogen compound that, in combination with high operating temperature and a quartz bulb envelope, gives even higher output. In halogen bulbs, the halogen cycle causes tungsten that boils off the surface of the bulb element to be redeposited onto the element. This prolongs the operating life of the element and keeps the bulb from blackening (at normal operating temperatures). Frank Krygowski
