Compact fluorescent lamps (CFL) originally emerged in the mid 20th century with mainstream adoption starting in the late 20th century. Typical household screw in replacements of the standard incandescent bulb are considered integrated CFLs.  This means that the tube and the ballast come together.  Ballasts are circuit boards with various electronic components that convert household AC power to a high frequency which is applied to the gas filled tube. 

 

Advantages:

• Use ~30% of the electricity of their incandescent counterparts

• Last between 6 - 15 times longer than incandescent

• Because of the longer life, better suited for difficult to reach locations

• Specialized bulbs for specific applications (i.e.: dimming, cold weather)

 

Disadvantages:

• Common bulbs are not suited to work in all environments (dimming applications, cold weather, outdoor, inverted)

• Fewer choices for color

• Bulbs contain mercury which must be disposed of specially

• Most have a warm-up time to reach full light output