Light bulb

Figure 1. An incandescent light bulb.[1]

A light bulb is an energy conversion device that converts electrical energy into light. Modern incandescent light bulbs (see Figure 1) are highly inefficient, with about 90% of the energy supplied to them being lost as heat.[2] This inefficiency sparked a need for a variety of more efficient electrical lights, which spawned several alternatives to the traditional incandescent light bulb. These include:


  1. Flickr [Online], Available:
  2. Bulbs. (Accessed Sept. 3, 2015). A brief history of the light bulb [Online], Available: