Special, life-extending, ballasts are available for lamps Lamp, it is cheaper to turn fluorescent lighting off if you will not need it forġ5 minutes or more. Nonetheless, when the cost of electricity is balanced against the cost of a The more often aįluorescent is switched on and off, the shorter its life and the faster it dims. Left on continuously will probably outlast its rated life. The rated life is the time by which half the bulbs have failed. Groups of lamps in a cycle of 3 hours on and 20 minutes off until all the lampsįail. Manufacturer's ratings of fluorescent lamp life are based on operating The ballast factor is not simply a characteristic of the ballast, since it also depends on the attached lamps. The ballast factor is the fraction of the initial lumens that the lamp provides if it is powered through that ballast, compared to the lumens the same lamp would produce powered through a reference ballast. How high depends on the length of the lamp.Īn important characteristic of a ballast is its ballastįactor. The pulse of electricity that starts the lamp is at a much higher voltage than

When they are, the fixture shorts the two pins together to become a single pin.) (Some T8 medium bipin lamps can be used with an instant start ballast. In an instant start lamp, only one connection is required at each end of the two connectionsĪt each end pre heat requiring a starter) or When the lamp is started, theįilaments heat, vaporizing liquid mercury within the tube. much like the filament in an incandescent bulb.

The type of ballast a lamp needs is related to how it starts. Electronic ballasts programmed start) In general, each type of ballast corresponds to a type of fluorescent lamp. There are three main types of ballast: pre-heat, rapid start, and instant start. The fixture, typically two, though as many as four. The production of magnetic ballasts after 1 January 2009,Īlthough replacements will still be available for residential use only.īallasts are usually made so that a single ballast powers all the lamps in An electricianĬan retrofit some older fixtures with an electronic ballast.īy 2001, more electronic ballasts were being sold Over 20,000 Hz, above the range of human hearing, which also eliminates theįlicker which annoys many people, and increases the light output. It can raise the frequency of the current going to the lamp to Which uses about 40% less energy than a magnetic ballast. Transistors made possible another type of ballast, the electronic ballast, Magnetic ballasts, not the lamps themselves, are the source of the hum formerly associated with fluorescents. Unfortunately the sheets move a very small amount as alternating current passes through the ballast. Such ballasts are called magnetic ballasts. In most of the 20ᵗʰ century, ballasts were black metal boxes in the lamp housing, their insides constructed something like an electrical transformer, of many thin sheets of special steels. The ballast provides the initial surge and then later limits the current. Once the lamp lights, the stuff inside the tube becomes a goodĬonductor of electricity – too good – and then some way of preventing too muchĬurrent from flowing through the bulb must be provided. To turn on a fluorescent lamp, a high-voltage pulse of electricity must be It does not mean a fixture (the thing with lamp holder sockets). In these entries, the word “lamp” means a fluorescent light bulb.

2 inch diameter circle actual size