Bulbs can refer to a variety of electrically sourced lighting. Today we take light bulbs for granted, but they are something we couldn't do without.
Incandescent Light Bulbs
The modern incandescent light bulb is the most popular and simplest light bulb. Using only a few parts, they have two metal contacts at the base which are connected to electrical current. The metal contacts attach to stiff wires, which are in turn attached to a thin metal tungsten filament. The filament vibrates and heats the inert gases contained by the glass bulb in order to create visible light.
Incandescent bulbs are widely used in domestic lights, portable lighting, some headlights, and flashlights, and are particularly popular in situations where light needs to be focused and concentrated on a particular point.
Fluorescent Light Bulbs
New bulbs offer advantages the incandescent light bulb can't. The fluorescent lamp uses electricity to excite mercury vapor or neon gas contained within a bulb, which results in short-wave ultraviolet light that causes phosphor to fluoresce, or illuminate, into visible light. They differ from incandescent in needing a ballast to regulate the electrical flow through the lamp. Compact fluorescent bulbs are much more energy efficient that their incandescent counterparts, because much of the energy transformation in an incandescent bulb is lost as heat. So, while fluorescent bulbs are more expensive than incandescent, they can lower energy costs and lamp replacement costs.
Conserving Energy with Fluorescent Bulbs
According to Energy Star, if every household in the U.S. replaced one incandescent light bulb with a fluorescent one, it would prevent one million cars worth of pollution. However, some people, especially those with Meniere's disease or epilepsy, are bothered by the flicker-fusion strobe effect of a fluorescent light. This effect can also cause safety concerns in workshops and problems for visual recording.
High-Intensity Discharge (HID) Lighting
High-Intensity Discharge (HID) lamps use an arc discharge contained within a refractory envelope to create light. Compared to incandescent and fluorescent lights, they emit a much larger quantity of light in a smaller source, and are typically used for gymnasiums, public areas, warehouses, parking lots, and other large public areas.
Solid State Lighting (SSL)
Solid State Lighting (SSL) uses Light-Emitting Diodes (LED) as illumination instead of filaments or gas. This creates light with almost no energy loss due to heat or other cause. This combined with their resistance to shock and vibration, long lifetime, low power consumption, and flexible application, indicate SSL bulbs will be a major force in the light bulb market in years ahead. They are currently too expensive for mass production.