الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Fluorescent lamps have been widely utilized in illumination for a long time owing to their high lighting efficacy and colour development. Unfortunately, they cannot be directly connected to utility lines owing to their discharge characteristics. Normally, they require high starting voltage for ignition, current-limiting device and operating voltage for sustaining discharge and normal operation. Typically, connecting a lossless networks consisting of a nonlinear inductors or high¬leakage transformers, sometimes in combination with capacitors, which are called the electromagnetic ballasts in series with the lamps, is the simplest way to drive such a nonlinear load. However, because of the line-frequency operation of the Inductor, there are some deficiencies such as bulky volume, heavy weight, audible noise, distorted current, low efficiency, low power factor and Line-frequency tlickering.
In recent years, electronic ballasts have attracted research interest in the ameliorati, on or alleviation of such deficiencies. Numerous benefits can be obtained by high frequency operation of fluorescent lamps. Flicker falls to unnoticeable levels. For the same input power, the lumenious output of a lamp operated at high frequency is 10--20% more than 50 or 60 Hz operations. Also, starting voltages decrease with increasing frequency, Improvements in the ballast can also be realized. At high frequencies inductors and capacitors C£ln be much smaller, both numerically and physically, to realize the needed current limiting impedance. This results in a substantial weight savings. Also, the hum heard from traditional electromagnetic ballasts would be eliminated.