Introduction

Lighting Induction lamps are high frequency (HF) light sources, which follow the same basic principles of converting electrical power into visible radiation as conventional fluorescent lamps.

" The fundamental difference between
induction lamps and conventional lamps
is that the Induction Lamps operate
without electrodes. "


Conventional fluorescent lamps require electrodes to connect the discharge plasma to an electrical circuit and inject electrons into the plasma. Fluorescent lamps normally operate on ac current at a frequency of 50 Hz or at HF of 40 to 100 kHz when driven by electronic ballasts. Thus, each electrode operates for one-half period as a cathode and the other half period as an anode. The production of electrons from electrodes is due to thermionic emission. The presence of electrodes in fluorescent lamps has imposed many restrictions on lamp design and performance and is a major factor limiting lamp life.


Induction lighting is based on the well-known principles of induction and light generation via a gas discharge. Induction is the energy transportation through magnetism. Practical examples are transformers, which consist of ferrite cores or rings with primary coils and secondary rings via the mercury vapor inside the lamps. An alternative current lp through the primary coil induces an alternative magnetic field in the ferrite core or coil. The alternative magnetic field in turn induces an alternative secondary current in the secondary coil or ring (Is). The efficiency of the lamp is proportional to the operating frequency of the driving alternative current.