Induction lamp

The induction lamp, electrodeless lamp, or electrodeless induction lamp is a gas-discharge lamp in which an electric or magnetic field transfers the power required to generate light from outside the lamp envelope to the gas inside. This is in contrast to a typical gas-discharge lamp that uses internal electrodes connected to the power supply by conductors that pass through the lamp envelope. Eliminating the internal electrodes provides two advantages:

  • Extended lamp life (internal electrodes are the most limiting factor in lamp life, since their metal content gets sputtered onto the lamp ends every time they are turned on)
  • Ability to use higher-efficiency light-generating substances that would react with internal metal electrodes in conventional fluorescent lamps

Two systems are common: plasma lamps, in which microwaves or radio waves energize a bulb filled with sulfur vapor or metal halides, and fluorescent induction lamps, which are like conventional fluorescent lamp bulbs that induce current with an external or an internal coil of wire via electromagnetic induction.