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Light Bulbs - How do they work?

Incandescent light bulbs have been around for many decades and are still used in the majority of homes around the world. An incandescent bulb has a few basic parts.


First, there's the bulb that you're used to seeing. A bulb is typically a glass ball containing a vacuum, meaning it has has most of the the air sucked out of it.


What happens inside the bulb? Incandescent bulbs contain a long, coiled, piece of metal called a filament. In fact, an average 60 watt bulb has over 6 feet of filament wire inside of it!


When you turn on a light bulb, electricity flows through the filament. As the filament heats up it produces light. The color of the light depends on the temperature of the filament.

Why does the bulb contain a vacuum? If the bulb had air inside of it the filament would quickly heat up and essentially burn up. However, a light bulb contains a vacuum or a specialized gas that doesn't allow the filament to burn.

Incandescent bulbs are simple but fairly inefficient. Most of the electricity flowing through the filament generates heat while a small percentage actually produces light. That's why light bulbs get quite hot to the touch. They're essentially heaters generating a small amount of light. This low level of efficiency is also why there's a huge push to switch to more efficient fluorescent and LED lighting.

Light bulbs eventually burn out because their hot filaments deteriorate over time. Eventually the filament becomes so weak that it breaks and electricity can no longer flow through the bulb. At this point the bulb not longer produces light and has burned out.

Because of their higher efficiency, compact fluorescent bulbs and other newer types will become more common in the future. These other types of bulbs operate in a totally different way. Stay tuned for a future Wydea video on this topic.

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