24 August 2018
Fluorescent Lamps Have Evolved to Offer More Efficient Lighting Solutions
Invented by one Peter Cooper Hewitt in 1903, the mercury vapour lamp is generally regarded as the precursor of the fluorescent lamps that were destined to become popular towards the end of the 1920s. Both used an electric current to excite a gas sealed within a tube, which then produced short-wave ultraviolet light. It was, however, the addition of a phosphor coating on the inner surface of the tube that turned this early device into a practical source of illumination. The ultraviolet radiation causes the phosphor coating to fluoresce, thus increasing the overall brightness of the modified device.
While the incandescent tungsten filaments, developed by pioneers such as Edison, produced adequate illumination, of between 50 and 100 lumens per watt, fluorescent lamps proved to be markedly more efficient at the job of converting electricity into light. There was, however, one factor that still left some consumers a little reluctant to abandon their tungsten globes. Because the newer product required a means with which to regulate the flow of the current, the inclusion of the in-line device known as an electrical ballast, meant that its purchase price was correspondingly higher. That said, it quickly became apparent that the lower cost of operation soon covered the cost of purchase and, thereafter, would continue to provide consumers with long-term savings.
Compared with those in use today, these early fluorescent lamps still displayed a number of disadvantages in addition to their high price and somewhat bulky structure. Among the more significant of these were the risk of exposure to toxic mercury when tubes were broken, a tendency to flicker that could cause problems for migraine sufferers and epileptics, and the lack of any effective means with which to reduce their intensity, should this be necessary.
Fortunately, the modern product has successfully overcome all of these former disadvantages and is also more energy efficient than its predecessors. Known as CFLs or compact fluorescent lamps, the most noticeable difference is that the tubular structure of the new models has been folded into spirals or loops, with the result that they are no larger than a tungsten globe. Almost totally free of that annoying flickering effect, they use a smaller and more efficient ballast, different from the older units, which when faulty, often caused earlier designs to produce a rather annoying, humming noise.
While not all models are compatible, the illumination from selected CFLs can be controlled very effectively with the use of a dimmer switch. Although LEDs are even more energy-efficient, CFLs are still about 70% more energy efficient than tungsten globes.