Electric Light - Types

Types

Types of electric lighting include:

  • incandescent light bulbs
  • arc lamps
  • gas discharge lamps, e.g., fluorescent lights and compact fluorescent lamps, neon lamps, flood lamps, modern photographic flashes
  • lasers
  • light-emitting diodes, including OLEDs
  • sulfur lamps

Different types of lights have vastly differing efficiencies and color of light.

Name Optical spectrum Nominal efficiency
(lm/W)
Lifetime (MTTF)
(hours)
Color temperature
(kelvin)
Color Color
rendering
index
Incandescent light bulb Continuous 4-17 2-20000 2400-3400 Warm white (yellowish) 100
Halogen lamp Continuous 16-23 3000-6000 3200 Warm white (yellowish) 100
Fluorescent lamp Mercury line + Phosphor 52-100 (white) 8000-20000 2700-5000* White( various color temperatures), as well as saturated colors available 15-85
Metal halide lamp Quasi-continuous 50-115 6000-20000 3000-4500 Cold white 65-93
Sulfur lamp Continuous 80-110 15000-20000 6000 Pale green 79
High pressure sodium Broadband 55-140 10000-40000 1800-2200* Pinkish orange 0-70
Low pressure sodium Narrow line 100-200 18000-20000 1800* Yellow, no color rendering 0
Light emitting diode Line plus phosphor 10-110 (white) 50,000-100,000 Various white from 2700 to 6000* Various color temperatures, as well as saturated colors 70-85 (white)

*

The most efficient source of electric light is the low-pressure sodium lamp. It produces, for all practical purposes, a monochromatic orange/yellow light, which gives a similarly monochromatic perceprtion of any illuminated scene. For this reason, it is generally reserved for outdoor public lighting usages. Low-pressure sodium lights are favoured for public lighting by astronomers, since the light pollution that they generate can be easily filtered, contrary to broadband or continuous spectra.

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