What type of function does a bulb primarily serve in electrical systems?

The primary function of a bulb in electrical systems is illumination. Bulbs convert electrical energy into light energy, effectively providing visible light for various applications, including household lighting, streetlights, and decorative purposes.

When electricity flows through the filament or semiconductor materials in a bulb, it generates light by excitation of electrons or by heating a filament to a temperature that emits light. This fundamental purpose of creating light distinguishes bulbs from other types of electrical components that may serve entirely different functions, such as power transmission or heat resistance.

While bulbs can generate heat as a byproduct, that is not their main purpose. Mechanical support is also not relevant, as the support structure is only incidental to the light-generating function of the bulb. Understanding that illumination is the primary role of a bulb helps clarify its value and application in various electrical systems.