1. Incandescent bulbs are the original form of electric lighting and have been in use for over 100 years. While Thomas Edison is widely considered to be the inventor of the incandescent bulb, there are a number of people who invented components and prototypes of the light bulb well before Edison did. One of those people was British physicist Joseph Wilson Swan, who actually received the first patent for a complete incandescent light bulb with a carbon filament in 1879. Swan’s house was the first in the world to be lit by a light bulb. Edison and Swan merged their companies and together they were the first to design a bulb that was commercially viable. History of the light bulb How does an incandescent light bulb work? How much energy do they use? The incandescent light bulb or lamp is a source of electric light that works by incandescence, which is the emission of light caused by heating a filament. They are made in an extremely wide range of sizes, wattages, and voltages. What are they? Light bulb safety Modern light bulbs and CFLs are safer than the old candles and lamps they replaced, but they still need to be handled carefully. If a regular light bulb breaks there will be sharp glass that needs to be cleaned up. It can be even more dangerous if a CFL breaks, though, because the chemicals inside are poisonous, especially a a liquid metal called mercury. If one does break, stay away until an adult cleans it up. A light bulb has three main parts: a metal base that conducts electricity, a thin wire called a filament and a glass bulb that surrounds and protects the filament. The bulb protects the filament by keeping air away from it. When the electricity pushes its way through the filament, the filament heats up and gets so hot that it begins to glow. The filament glows brightly enough to create light. Why make the switch? The horse-and-buggy era light bulb we still rely on, wastes up to 90 percent of the electricity it consumes as heat, burning up hundreds of dollars every year in each American household and increasing air pollution that harms human health and the environment. Beginning in 2012, new energy efficiency standards will phase out the inefficient incandescent light bulb that dates back more than 125 years, and require new bulbs to use 25 to 30 percent less energy. The transition to more efficient light bulbs will provide massive consumer, public health, and economic benefits. Just imagine the following benefits: Savings of $100 to $200 plus per year in the form of lower electric bills in each American household Energy savings equivalent to 30 large power plants Reductions in carbon pollution of approximately 100 million tons of carbon dioxide (CO2) per year (equivalent to the annual carbon pollution from more than 17 million cars.) Replacing all the nation's inefficient bulbs with energy efficient ones will save as much electricity annually as that consumed by all the homes in Texas. Parts of a Light Emitting Diode (LED) bulb Parts of an Incandescent light bulb Parts of Compact Fluorescent Light (CFL) bulb There are two main parts in a CFL Bulb: 1. 1.The gas-filled tube (called the bulb or burner is filled with argon and a small amount of mercury vapor) 2. 2.The magnetic or electronic ballast. Electrical energy in the form of an electrical current from the ballast flows through the gas, causing it to emit invisible ultraviolet light. The ultraviolet light then excites a fluorescent white phosphor coating on the inside of the tube. This coating emits visible light. How does a LED light bulb work? Stated very simply, a LED produces light when electrons move around within its semiconductor structure. A semiconductor is made of a positively charged and a negatively charged component. The positive layer has "holes" -- openings for electrons; the negative layer has free electrons floating around in it. When an electric charge strikes the semiconductor, it activates the flow of electrons from the negative to the positive layer. Those excited electrons emit light as they flow into the positively charged holes. A LED is a "solid-state lighting" technology, or SSL. Instead of emitting light from a vacuum (like an incandescent bulb) or a gas (like a CFL), an SSL emits light from a piece of solid matter. That piece of matter is a semiconductor. http://www.bulbs.com/learning/incandescent.aspx http://www.sielement.com http://www.gardnerkansas.gov/cfl_light_bulb_information/

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