Lighting makes up 20% of electricity use in the United States. Greater use of fluorescent lighting would reduce energy use. Now a newly patented device from theCenter for Power Electronic Systems (CPES) at Virginia Tech(Blacksburg, VA) has the potential to make fluorescent lighting even more efficient and desirable for many applications.

"Although fluorescent lights are about four times more energy efficient and last longer than conventional incandescent lighting, they are actually still wasteful," says CPES director Fred Lee. Every fluorescent light requires a ballast to provide starting voltage and limit current. With standard magnetic ballasts presently in use, only 60% of every watt results in light, Lee estimates.

Now Lee has received a patent for an electronic ballast that solves the problem of the traditional magnetic ballast and allows fluorescent lights to be dimmed. "Electronic ballasts reduce energy consumption by as much as 30%," says Lee.

The patent for the "Self-oscillating Electronic Discharge Lamp Ballast with Dimming Control" was awarded June 20, 2002 to Virginia Tech graduate student Fengfeng Tao of Blacksburg, Va., and Lee, a university distinguished professor of electrical and computer engineering at Virginia Tech. Electronic ballasts increase the life of the bulb and make for brighter lighting, which now can be dimmed as desired by the user.

Electronic ballasts are not new. However, "the cost of manufacturing electronic ballasts has been too high," says Lee. But not the new ballast, which is less complicated and thus less costly to manufacture. CPES ( is a National Science Foundation Engineering Research Center, established in 1998 to bolster research to make power electronics more efficient and the United States a leader in power electronics. Virginia Tech is the lead institution of the CPES consortium of five universities and more than 80 industry partners.

Source: Virginia Tech