Parts of the Lamp Bulb

The humble lamp bulb has been illuminating our homes and businesses since the 1870s. It’s a bit of a marvel how it works – a thin filament of hard-to-melt metal (usually tungsten) encased in a glass bubble filled with inert gas to prevent it from oxidising and disintegrating. It’s powered by electricity, and it gives out light as a by-product of the electrical energy being turned into heat. It hasn’t changed a whole lot since its invention but it does have quite a few different parts to it. James May takes a look at these parts and how they work together to create that bright white light you see every day.

The first successful light bulbs had carbon filaments until tungsten ones were developed in the 1900s. They last longer and produce a better-looking light than their carbon counterparts. Carbon filaments were prone to blackening over time and required frequent replacement, making early bulbs costly and inefficient. The tungsten filaments were developed to overcome this problem. They are much less susceptible to blackening and are more heat-resistant than carbon, allowing them to be used at higher temperatures and extending their life.

Besides the type of filament, there are other important considerations when choosing a light bulb for a particular application. Bulb efficiency, for example, is a key factor when choosing the right one to power your home’s lighting. Also called luminous efficacy, it is the ratio of a lamp’s emitted light to its power consumption measured in lumens per watt (lm/W). The higher the efficacy, the more efficient a bulb is.

Another thing to take into account is the bulb’s shape. There are various shapes to choose from, depending on the desired effect. For instance, a simple and elegant design is found in the Formakami from &tradition, a contemporary lamp inspired by Asian rice paper lanterns that has a minimalistic expression.

In addition to the type of filament and the shape, there are many other things to consider when choosing a light bulb for your space. For example, there are different base types – the most common are the A-type or standard bulbs with an Edison screw that’s typically used in households. Other common options include the E27 and E14 screw-in bases as well as the CFL and LED bases.

The base of the bulb provides both the electrical connections and mechanical support. It is connected to the bulb by either cement or a screw-in connection. Bulb bases come in a variety of sizes, shapes and finishes. They can also be fitted with alignment features to ensure the filament is positioned accurately within the optical system of a fixture.

Most modern light bulbs use a vacuum to protect the filament from oxygen and increase its longevity. In addition, a vacuum reduces the evaporation of the filament and allows more electricity to be turned into heat. Some smaller bulbs use argon instead of a vacuum to improve their efficiency. Krypton is a more effective alternative to argon but is significantly more expensive, restricting its usage to small bulbs.