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.

Read more about this topic:  Electric Light

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