page_title: Compact fluorescent lamp
section_title: Power factor
hierarchical_section_title: Compact fluorescent lamp / Characteristics / Power factor
caption_attribution_description: English: Voltage and current waveforms for a 30 watt 120 volt compact fluorescent lamp. Although the average current is only about 0.5 ampere, the current waveform is quite distorted and has many harmonics. As a result this lamp shows a power factor of 0.61 while using about 29 watts. Image captured with a Fluke 192C Scopemeter.
context_page_description: A compact fluorescent lamp, also called compact fluorescent light, energy-saving light and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent light bulb; some types fit into light fixtures designed for incandescent bulbs. The lamps use a tube which is curved or folded to fit into the space of an incandescent bulb, and a compact electronic ballast in the base of the lamp.
  Compared to general-service incandescent lamps giving the same amount of visible light, CFLs use one-fifth to one-third the electric power, and last eight to fifteen times longer. A CFL has a higher purchase price than an incandescent lamp, but can save over five times its purchase price in electricity costs over the lamp's lifetime. Like all fluorescent lamps, CFLs contain toxic mercury which complicates their disposal. In many countries, governments have banned the disposal of CFLs together with regular garbage. These countries have established special collection systems for CFLs and other hazardous waste.
context_section_description: The input stage of a CFL is a rectifier, which presents a non-linear load to the power supply and introduces harmonic distortion on the current drawn from the supply. The use of CFLs in homes has no appreciable effect on power quality, but significant quantities of them in a large facility can have an impact. The power factor of CFLs does not significantly affect their energy-saving benefits for individual consumers, but their use in large numbers—such as in commercial applications or across millions of homes in a distribution system—could require infrastructure upgrades.  In such cases, CFLs with low (below 30 percent) total harmonic distortion (THD) and power factors greater than 0.9 should be selected.
caption: Voltage and current for a 120 V 60 Hz 30-watt compact fluorescent lamp. Because the current is heavily distorted, the power factor of this lamp is only 0.61. The lamp takes 29 watts but 39 volt-amperes due to this distortion.
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