Neon lamps are gas discharge lamps that contain neon gas at a low pressure, enveloped in a glass capsule. Gas discharge lamps emit light when electric light is passed through the gas. Neon lamps have been used widely in neon sign boards. They provide a distinct orange glow.
Neon lamps contain either neon gas or a mixture of neon and mercury vapor. They were developed in the year 1917 by Daniel Moore. Colors other than orange can be obtained from neon lamps by using different phosphors for coating the glass tube.
This article will provide details on the working, construction, and applications of neon lamps.
Working and Spectral Output
Gases are not good electric conductors at atmospheric pressure. A special tube, called the gas discharge tube, is used to maintain a low pressure for the gas. When electric current is applied between the two electrodes of the discharge tube, and a suitable pressure is reached, the gas starts to glow. Different gases emit different colors.
The neon lamp emits light of wavelengths that lie in the visible region of the spectrum. Neon lamps emit a distinctive orange glow.
A neon lamp is made of a discharge tube filled with 95.5% neon gas and 0.5% argon gas. The tube has electrodes sealed at both ends.
Neon lamps are used in a number of applications that are listed below:
- Sign boards
- Microwave detectors
- Electronic equipment
- Logic circuits, binary memories
- Used in LEDs, LCDs, and vacuum fluorescent displays
Sources and Further Reading
- Gases that emit light – University of Wisconsin
- Gas discharge lamps, ballasts and fixtures – Drexel University