Compact Fluorescent Light Bulbs - Version 2 These bulbs were a truly wonderful creation but they were often hard to install in fixtures due to their increased sizes. Over the years many manufacturers have improved upon that original design and created a magnificent product that allows the consumer to save money and reduce their carbon footprint without sacrificing light output. Compact fluorescent light bulbs work by sending current into the spiral tube which is filled with argon gas and a trace of mercury gas, this process actually emits an invisible ultraviolet light, and only becomes visible due to the phosphor coating on the inside of the tube. A ballast is required to start the current flow and regulate the voltage throughout the process.