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Robert Desbois Electronic Ballast Design for Fluorescent Lamps Operating From an Extra Low Voltage Battery Supply 12 Dove Walk, Elm Park, Hornchurch, Essex, UK Abstract Luminaire design can be enchanced by reliable design leading to high light output and low current consumption. The designer is always under pressure to maximise on lumens per watt. An obvious limitation is the light source itself, over the years these have improved considerably. For a "working light" good colour rendering is a very important consideration, where as general lighting such as street lighting can achieve much higher lumens per watt using low pressure sodium light source. This has the disadvantage of being monochromatic leading to poor colour rendition and slow build up of light output. Light sources are divided into 6 principal lamp types (Incandescent, Tungsten Halogen, Fluorescent, Mercury, Metal Halide and Sodium) with an efficacy ranging from moderate to very high, colour rendering from excellent to poor, liftetime from moderate to long and initial costs from low to high. Fluorescent lighting is a mid range light source with high efficacy, good rendering, long lifetime and medium initial cost. This is the recommended light source for photovoltaic operation. It needs a carefully designed and matched electronic ballast to operate successfully. This paper is intended to demonstrate the advantages of good circuit design to optimize the light source chosen and life expectancy along with producing maximum light to the area to be illuminated. Photovoltaic cells are relatively expensive. Doubling the efficiency of an electronic ballast can halve the capital cost of the array. Good luminaire design can also almost double the visible light radiation. A combination of correct light source, good electronic ballast design and efficient optic design of the luminaire is therefore vital.
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