Step into the Light: the Different Types of Light Bulbs
“And God said, let there be light: and there was light.”
Among the many inventions that history has blessed humanity with is the incandescent light bulb, perfected by Thomas Alva Edison in the year 1879. Efforts to create the electric light were on since 1802 Humphry Davis invented the electric arc lamp. These efforts were followed by Warren de la Rue, who in 1840 used platinum to improve longevity; Joseph Wilson Swan in 1850s-60s, who used carbonized paper filaments, cotton threads, and vacuum pumps to increase bulb life and; Henry Woodward and Matthew Evans, who in 1874 built lamps of different shapes and sizes until they sold their patent to Edison in 1879.
The initial electric lights he patented used "a carbon filament or strip coiled and connected ... to platina contact wires" only later to discover that a carbonized bamboo filament had a life of more than 1,200 hours. The Edison Electric Light Company began marketing its product in 1880.
The timeline of the lightbulb flew through 1906 when the General Electric Company used tungsten as the filament, then 1910 when the longest lasting tungsten filaments were invented, followed by the production of the first frosted lightbulb, adjustable power beams and neon lighting in the 1920s, the one-time flashbulbs for photography and fluorescent tanning lamps in the 1930s, the soft light incandescent bulbs in the 40s, the quartz glass and halogen light bulbs in the 50s, the low wattage metal halides in the 80s and the long life bulbs and compact fluorescent bulbs in the 90s.
Today, one can identify three major types of light bulbs. These are the incandescent bulbs, halogen bulbs, and CFL bulbs.
Major light bulb types
- Incandescent bulbs: These bulbs produce light when the thin tungsten filament is heated by electricity till it glows. They cast a warm glow but get very hot to touch and need to be replaced often and hence are inefficient. They have a Color Rendering Index (CRI) of 100 and emit 290 lumens at 40 watts.
- Halogen bulbs: These bulbs are generally found in the form of spotlights, headlights or stadium lights and are mostly used outdoors. They too have a tungsten filament, but they last longer due to the presence of halogen gas which redeposits the burnt filaments to continue the light's life. They are much brighter and hotter than incandescent bulbs and emit 940 lumens per 53 watts.
- Compact Fluorescent Light bulbs: These bulbs are built in a spiral form and are considered to be far more efficient than incandescent bulbs. They work by exciting the gas present in the coils when electricity passes through. A coating on the spirals makes the light white and these bulbs do not get as hot as incandescent bulbs. They emit 550 lumens on nine watts.
Other types of light bulbs
- Light Emitting Diode (LED): The invention of these bulbs won Shuji Nakamura, Hiroshi Amano and Isamu Akasaki the Nobel Prize for Physics in 2014. They are bright and energy saving blue lights, which look white to the eye. Blue lights do, however, have a negative impact on human health and wildlife.
- Metal Halide: These lights are generally used in the streets and in stadiums. They have good color rendition and produce white light.
- High-Pressure Sodium: These lights are used around the world as the best option for street lights. They run with electricity running through a mixture of gasses, take a while to turn on completely and emit a yellow-orange glow. They are quite efficient and require little maintenance.
Many other variations of light bulbs include Low-Pressure Sodium (LPS) bulbs, LED street lamps, Phosphor-Converted Amber (PCA) LED street lamps and Narrow-Band Amber (NBA) LED street lamps.