Incandescent Bulbs

Incandescent Lamp

How does it Work?

Light bulbs work on a very simple principle. When the metal is heated, it glows. The only problem is that it has to be heated up a lot.

Electricity comes into a light bulb via a hot wire connected to a tab on the base of the bulb. Inside the bulb the electricity goes through a wire leading to a piece of tungsten. The tungsten is very thin and coiled to maximize resistance in the wire. When electricity meets resistance, it heats up the resistor.

The tungsten gets to a temperature of approximately 4500 degrees Fahrenheit (2492 degrees in Celsius). This causes it to get white hot. It glows very brightly. Tungsten is used because it has a very high melting point. The tungsten is encased in a bulb for very good reason. It protects people and objects from the hot tungsten. It also keeps oxygen away from the hot metal, which would make it immediately burn up. The bulb is usually filled with a low pressure, inert gas such as argon. After electricity has made its way through the tungsten filament, it goes down another wire and out of the bulb via the metal portion at the side of the socket. It goes through into the fixture and out a white wire.

Incandescent bulbs are manufactured in a wide range of sizes, light output and voltage ratings from 1.5 volts to approximately 300 volts.