Fluorescent Light

Fluorescent light is the most common type of electrical light found in the United States; it is used for practically all commercial lighting, i.e. offices, factories, stores and schools, and it is estimated that there are 1.5 billion fluorescent lamps in use nationwide. Fluorescent lighting is popular due to its high efficacy, i.e. it produces between three to five times more light than an incandescent lamp consuming the same electrical power. The main reason for this is that the fluorescent lamp employs a phosphor which converts the non-visible light produced by the lamp into visible light, whereas a large fraction of the output from the incandescent lamp is infra-red light which escapes as heat.

Although the fluorescent lamp was first demonstrated by Becquerel in the 1860s, it was not commercially available until 1938 with the introduction of phosphors which could withstand the rigors of operation for a reasonable length of time. Since then improvements have been made in all aspects of the lamp: electrodes, phosphors, gas mixtures, and control circuitry. These improvements are particularly important simply because there are so many fluorescent lamps in use. Over its lifetime, a standard fluorescent lamp consumes as much electricity as is generated by a barrel of oil: the importance of even small increases in efficacy become apparent when one considers that even a 10% increase will result in savings of approximately 40 million barrels a year in the United States alone.