They may look the same But they’re not

by Tom Gregg

CFLs (Compact Fluorescent Lamps) performance in both lamp life and light is dependent on the electronic ballasting in the base of the lamp.

Manufactures vary in circuitry design. The number of electronic components can range from 16 to a high of 36. Performance and price are affected not only by the ballast design, but also the quality and tolerances of the individual parts themselves. These parts are rated in plus or minus tolerance. A component with a +/- 5% will operate better than the less expensive component that is rated at +/- 10%.

Heat is a prime concern as these components havelimits. All CFL ballast have electrolytic capacitors. They are the cylinder objects in the photograph. The electrolytic capacitor contains a liquid that can be depleted and cause premature failure if the operating temperature is exceeded. The better quality CFLs have designed product to be operated in commercial applications in any burning position. This ability to tolerate higher heat from longer burning hours gives these CFLs a longer life expectancy and maintained light output.

Why do capacitors fail?

Electrolytic capacitors use a semi-liquid electrolyte inside the case to make electrical contact with the foil windings. This electrical interface is inherent in the capacitor’s ability to carry current and function as an energy storage unit for the electrical power input. When the interface between the electrolyte and the metallic foil windings begins to degrade, the electrical connection begins to fail. Heat build up is the primary cause of this degradation, which, depending on severity, can cause either short-term catastrophic failure, or long term functional degradation. Similar to the life expectancy of a silicon semiconductor die, the life expectancy of an electrolytic capacitor relates directly to its internal temperature. Every 10° C increase in internal temperature halves the component lifetime.

“Test results for the above are based on CFLs from low cost retailers. Product designed for the residential buyer. “

Summary:
The photograph on the first page shows the internal workings of twelve different CFLs out of the more than twenty we examined. All are different. The price is also different. The commercial CFLs have more durable parts, and in some CFLs the addition of heat shields and heat sinks. These are usually found in base up operations such as Par and Reflector lamps. The quality and value of the compact fluorescent spiral is directly proportional to the quality of the internal electronic components.