The fluorescent lamp is a low-pressure discharge lamp comprising a glass tube with electrodes at both ends. The tube is filled with argon or krypton gas plus a small amount of mercury. The tube also contains a quantity of inert air for faster starting. On the inside the glass tube is coated with a thin layer of fluorescent powder. When a current is passed through the tube, the gas discharge produces mainly invisible ultraviolet light, which is only converted to visible light when it penetrates the powder coating.
Fluorescent lamps offer long service life, high luminous output and good colour rendition, and are therefore used for a wide range of lighting requirements. They are operated with a ballast and starter.

Advantages


  • High luminous output (75-95 lm/W)
  • Wide range of wattage
  • Good to very good color rendition
  • Long lamp life (7,500 -12,000h)


Disadvantages

  • Size