This document compares compact ELV (Extra Low Voltage) tungsten halogen lamps to gas discharge lamps. Compact ELV tungsten halogen lamps have advantages such as a smaller and more robust filament allowing better beam control, higher efficacy and lower running costs, better lumen maintenance, longer lamp life up to 3500 hours, and less heat generation. However, they require heavier wiring to carry the higher current of the low voltage and adequate ventilation for the transformer with a higher initial cost.

1. Compact ELV (Extra Low Voltage) Tungsten Halogen Lamp • Heavier wiring required to carry higher current necessary for the low voltage. • Adequate ventilation required for the transformer. • Higher initial cost. • Smaller and more robust filament and has better beam control • Higher efficacy, therefore lower running costs • Better lumen maintenance due to no lamp blackening • Longer lam life up to 3500 hours • Less heat generated especially with “dichroic” filters • Used often for outdoor or in underwater lighting in pools • Sizes: 20W, 50W, 75W Disadvantages Advantages

2. Gas discharge lamps

3. Hot Cathode – Fluorescent Lamps

4. Hot Cathode Operation