6022 Optoelectronics

Incandescent lamps are the most widely used type of lighting source across the world due to its wide range of applications. An incandescent lamp is an electric lamp that uses a heated filament in an enclosed, evacuated vessel as its light source. The filament typically contains a metallic conductor such as tungsten, which is heated to extreme temperatures until it emits visible light. Incandescent lamps are often referred to as ‘ordinary’ or ‘normal’ lamps.

A key feature of an incandescent lamp is its ability to last a long time – typically up to 2,000 hours of continuous use. The working principle behind an incandescent lamp is based on the theory of Joule heating, which states that when an electrical current passes through a conductor, the conductor heats up due to the resistance it experiences. This is put to good use in the construction of an incandescent lamp, where an electrical current is passed through a tungsten filament, heating it up and thereby causing it to produce light.

Neon lamps are another type of lighting source which utilizes the emission of light produced by a voltage-induced electrical current through an inert gas-filled tube. The gas which is used in the tube is typically a noble gas such as neon, xenon or argon, although other gases such as mercury vapor have also been used. When an electrical current is passed through the tube, the gas ionizes and the resulting light emissions have a characteristic ‘neon’ glow.

The working principle of a neon lamp is based on the fact that different energies are required to remove different numbers of electrons from an atom. When the electric current passes through the inert gas-filled tube, it is applied to the gas atoms at different levels, resulting in some of the electrons being removed from the atoms and causing them to become highly energetic ions. The ions move rapidly back and forth between the electrode inside the tube, resulting in the emission of light.

Both incandescent lamps and neon lamps can be used for a wide range of lighting applications, from lighting homes and offices to street lighting and decorative lighting. Incandescent lamps are typically used in applications where a soft, warm light is desired, while neon lamps are often used in applications where a bright, directional light is needed.