Gas discharge lamps are artificial light sources producing light when an electric discharge is sent through an ionized gas. It often includes two electrodes that differ between wattage bulbs hence having a varying light intensity. Different types of gas discharge lamps are thus applied in a wide array of uses industrially.
How Gas Discharge Lamps Work
Typically, discharge lamps use gases to excite electrons, which sequentially generates light useful for any given application. These lamps consist of one or a mixture of noble gases, while most of them are filled with additional content such as mercury and metal halides. When lighting, the gas gets ionized, allowing free electrons to collide with the gas and metal atoms once the ionization is accelerated.
Other electrons in atomic orbitals are excited as well due to the collision to the maximum energy state. When they fall back to a decreased energy state, protons are released with characteristic energy leading to infrared, visible light, and ultraviolet radiation. The process often takes microseconds to produce instant light.
Types of Gas Discharge Lamps
Gas discharge lamps are categorized depending on the pressure of gas and if the cathode is heated. Hot cathode lamps include electrodes operating at high temperatures when heated by arc currents within the lamp. In most cases, electrodes have electrical filaments heated to startup the arc for the lighting before ionizing the gas.
Low-Pressure Discharge Lamps
Fluorescent lamps are the most common low-pressure lamps, including a heated cathode commonly used in office lighting. These lamps produce up to 100 lumens per watt neon lighting, equipped with a bi-metallic switch to start the lighting. Based on the shape of the fluorescent, the gas’s ionization varies, which is also determined by the type of gas used.
High-Pressure Discharge Lamps
Unlike low-pressure discharge lamps, high-pressure lamps ionize the gas slightly under less to greater than atmospheric pressure. These are the oldest forms of mercury-vapor lamps replaced by metal halide and pressurized sodium lamps applied in various areas. High-pressure lamps require a shorter arc under 100 to 200 torr pressure to start heating, ionizing, and producing light. Besides, they produce up to 150 lumens per watt, greater than low-pressure lamps.
High-Intensity Discharge Lamps
This type of electric lamp produces light with an electric arc between tungsten electrodes enclosed within a translucent or transparent fused quartz or tube. The arc power is relatively higher and is often used when maximum energy levels at efficient energy are needed. Examples of high-intensity discharge lamps include sodium vapor lamp, mercury-vapor lamp, and Xenon flash lamp.
Uses of Gas Discharge Lamps
Gas discharge lamps are crucial in high efficacy maintenance of luminosity for an extended period. They are used in various industries determined by the type of gas like mercury, which promotes brightness. Other uses include the design of neon signs, outdoor arenas, generating ozone, and in hospitals to sterilize objects.
Though they are standard lighting tools in homes and industries, gas discharge lamps apply in various industries to facilitate operations. However, the usage differs based on the type of gas and discharge lamp used.