How Does A Discharge Lamp Work? The discharge lamps work on the fundamental principle that, light is emitted when the electrons have collided with each other. To obtain this, the first gas an ionized at very high voltage.
How is light produced in an electric discharged lamp?
- Lsleds How is light produced in an electric discharged lamp? Light can be produced by establishing an electric arcs in a gas. The process of electric discharge is called gaseous discharge. As it glows through the glass, it gets light from the arcs inside the lamp.
What is the difference between discharge tubes and discharge lamps?
Discharge tubes were made as early as 1856, but commercially discharge lamps came into the market only in the 1930s. Gas-discharge lamps are a family of artificial light sources that emit light by sending an electrical discharge through an ionised gas, i.e. plasma.
What is a gas discharge lamp?
The fluorescent lamp is perhaps the best known gas-discharge lamp. The spectral energy distribution of the electrical discharge lamp depends primarily on the type of vapour or gas, vapour pressure, the nature of electrode and the electrical energy.
What are high-intensity discharge lamps?
High-intensity discharge lamps ( HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. This tube is filled with noble gas and often also contains suitable metal or metal salts.
How do discharge lamps give Coloured light?
The colour of the light inside the lamp depends on the gas. For example, Sodium vapour represents yellow colour, Neon gas gives orange-red colour. Similarly, chlorine gas gives out green colour from the discharge lamp.
What is the purpose of the LED discharge lamp?
The discharge lamp/ballast allows it to be dimmed and set to hibernation mode when not in use.
What is disadvantage of discharge lamp?
Disadvantage of Electric Discharge Lamps They require some starting mean like starter or starting transformer. In case electric discharge lamps, the flicker causes the stroboscopic effect. They require some time to attain full brilliancy. Electric discharge lamps have poor power factor.
Do gas discharge lamps require a ballast?
All gas discharge lamps, including fluorescent lamps, require a ballast to operate. The ballast provides a high initial voltage to initiate the discharge, then rapidly limits the lamp current to safely sustain the discharge.
What does discharge lamp mean?
Definition of discharge lamp : an electric lamp in which an enclosed gas or vapor glows or causes a phosphor coating on the lamp's inner surface to glow.
Is arc lamp a discharge lamp?
The term is now used for gas discharge lamps, which produce light by an arc between metal electrodes through a gas in a glass bulb. The common fluorescent lamp is a low-pressure mercury arc lamp.
What are the advantages of using discharge lamp?
Loss of electricity in the form of heat is less, more life span, no shadow formation, more light is obtained, less consumption of electricity. Was this answer helpful?
Is LED is a discharge lamp?
LED gas-discharge lamps are an ideal alternative to conventional gas-discharge and HID lamps. Traditionally, gas-discharge lamps are used in industrial settings as well as retail. Since 2015, more and more of them have been phased out due to the harmful substances they contain as well as their inefficiency.
What is the advantage of discharge lamp over incandescent lamp?
Less consumption of electricity: Discharge lamps consume less electricity in comparison to incandescent lamps because in later lamps to spread light continuous electric current is required while in former lamps electricity requires only to create plasma, once created it no longer needs electricity.
What are the gasses used in gas discharge lamp?
As shown in the diagram, a discharge lamp consists of one gas tube, wherein a gas at low pressure is maintained. The gas tubes are filled with noble gasses like argon, neon, krypton, etc. Additionally, they are also filled with sodium mercury amalgam. The sodium and mercury amalgam is required to draw an arc.
What kind of spectrum does a gas discharge lamp show?
There are gas discharge lamps which emit light on certain standard spectral lines as required mostly for spectral calibration purposes. Such lamps are called spectral lamps or based on their application as calibration lamps. The generated optical lines can be in the visible, infrared or ultraviolet spectral region.
Why do the gas discharge tubes need to be turned on before a color can be seen?
The excitation of electrons of a particular gas that emits a specific wavelength requires electricity. The electricity is required by the gases in order to cause excitation. Therefore, gas-discharge tube need to be turned on due to which the colour is seen.
Is LED lamp a discharge lamp?
Neon lamps for signs are also electric discharge lamps. The light-emitting diode (LED) is a form of luminescent lamp. The device is a crystalline semiconductor diode; when current flows through the diode, electrons combine with “holes” (localized positive charges) and drop to a state of lower energy.
Are LED lights electric discharge?
Electric Discharge is a method for producing light in which an electric current passes through the air or another gas such as neon. When electricity is discharged through the element neon, the neon glows intensely. LED (light emitting diode) is an electroluminescent light source made from a semiconductor.
Why are electrodes present in discharge lamps?
Gas discharge phenomenon is an essential characteristic of gas discharge lamps used in various lighting applications. When electric power is applied across the electrodes present inside a discharge tube, the electrodes give out electrons which bombard with the gas atoms introduced inside the discharge tube.
How the light output is produced in electric discharge lamp?
In all discharge lamps, an electric current is passed through a gas or vapour which renders it luminous. The elements most commonly used in this process of producing light by gaseous conduction are neon, mercury and sodium vapours. The colours (i.e. wavelength) of light produced depends on the nature of gas or vapour.
What is discharge lamp?
Discharge lamps come under the classification of artificial light sources that produce light by transmitting an electrical discharge via ionized gaseous substances. Usually, those lamps make use of either xenon, argon, krypton, neon, or a combination of these gases.
Why are discharge lamps so effective?
For the reason of intense light, these lamps have are highly effective, and are mostly used in huge indoor spaces and outdoor lighting purposes. As these discharge lamps need somewhat more time to create, they are appropriate for the application where they can remain for long hours.
How effective are HID lamps?
These lamps make use of electric arcs to deliver an intense range of light. Similar to fluorescent lamps, these also need ballasts. When initially turned on, these lamps require almost 10 minutes of time to generate light due to the reason that the ballast requires time to create the electric arc. For the reason of intense light, these lamps have are highly effective, and are mostly used in huge indoor spaces and outdoor lighting purposes. As these discharge lamps need somewhat more time to create, they are appropriate for the application where they can remain for long hours. The luminous effectiveness of the HID lamp is almost 3 times more than that of a halogen light, and this lamp life period is nearly 2000 h, which is only 300–700 h for a halogen light.
What is a xenon flash lamp?
A xenon flash lamp generates a flashlight either in the range of 10 -3 or 10 -6 and they are mainly employed for film and theatrical lights. Specifically, strong lamp versions called strobe lights can deliver a long period of flashes thus permitting the stroboscopic analysis of the motion. This is the example of a discharge lamp.
What is the pressure of a discharge lamp?
Mostly, fluorescent lamps which will be at domestic and office spaces function at an atmospheric pressure level of 0.3% and they generate nearly 100 lm W -1. Whereas minimal pressure range of sodium lamps which are the most powerful discharge lamps deliver nearly 200 lm W -1, but these have reduced color rendering characteristics.
Why do HID lights have white light?
The high-intensity discharge lamps also deliver a white color light than halogen lamps because their color spectrum is near to the solar spectrum range.
How much power does a halogen lamp save?
Generally, these are highly efficient lamps and they hold a tendency to provide extended service life for any type of these lamps. They will save almost 80 percent of lighting power when they are substituted in the incandescent lamps.
What is the difference between a gas discharge lamp and an incandescent lamp?
Compared to incandescent lamps, gas-discharge lamps offer higher efficiency, but are more complicated to manufacture and most exhibit negative resistance, causing the resistance in the plasma to decrease as the current flow increases . Therefore, they usually require auxiliary electronic equipment such as ballasts to control current flow through ...
When was the first gas discharge lamp invented?
Hauksbee first demonstrated a gas-discharge lamp in 1705. He showed that an evacuated or partially evacuated glass globe, in which he placed a small amount of mercury, while charged by static electricity could produce a light bright enough to read by.
How do hot and cold cathode lamps work?
Lamps are divided into families based on the pressure of gas, and whether or not the cathode is heated. Hot cathode lamps have electrodes that operate at a high temperature and are heated by the arc current in the lamp. The heat knocks electrons out of the electrodes by thermionic emission, which helps maintain the arc. In many types the electrodes consist of electrical filaments made of fine wire, which are heated by a separate current at startup, to get the arc started. Cold cathode lamps have electrodes that operate at room temperature. To start conduction in the lamp a high enough voltage (the striking voltage) must be applied to ionize the gas, so these lamps require higher voltage to start.
What is a Ruhmkorff lamp?
Ruhmkorff lamps were an early form of portable electric lamp, named after Heinrich Daniel Ruhmkorff and first used in the 1860s. The lamp consisted of a Geissler tube that was excited by a battery-powered Ruhmkorff induction coil; an early transformer capable of converting DC currents of low voltage into high voltages. Initially the lamp generated white light by using a Geissler tube filled with carbon dioxide. However, the carbon dioxide tended to break down. Hence in later lamps, the Geissler tube was filled with nitrogen (which generated red light), and the glass was replaced with glass containing uranium salts (which fluoresced with a green light).
How much pressure does a sodium lamp have?
For example, a high pressure sodium lamp has an arc tube under 100 to 200 torr pressure, about 14% to 28% of atmospheric pressure; some automotive HID headlamps have up to 50 bar or fifty times atmospheric pressure. Metal halide lamps produce almost white light, and attain 100 lumen per watt light output.
How many lumens does a fluorescent lamp produce?
Fluorescent lamps, a heated-cathode lamp, the most common lamp in office lighting and many other applications, produces up to 100 lumens per watt.
How does a fluorescent light bulb convert to visible light?
Some lamps produce ultraviolet radiation which is converted to visible light by a fluorescent coating on the inside of the lamp's glass surface. The fluorescent lamp is perhaps the best known gas-discharge lamp.
What is a high intensity discharge lamp?
High-intensity discharge lamps ( HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. This tube is filled with noble gas and often also contains suitable metal or metal salts. The noble gas enables the arc's initial strike. Once the arc is started, it heats and evaporates the metallic admixture. Its presence in the arc plasma greatly increases the intensity of visible light produced by the arc for a given power input, as the metals have many emission spectral lines in the visible part of the spectrum. High-intensity discharge lamps are a type of arc lamp .
Why do HID lamps need filters?
They are also used to reproduce tropical intensity sunlight for indoor aquaria . Most HID lamps produce significant UV radiation and require UV-blocking filters to prevent UV-induced degradation of lamp fixture components and fading of dyed items illuminated by the lamp.
What are the different types of HID lamps?
Various types of chemistry are used in the arc tubes of HID lamps, depending on the desired characteristics of light intensity, correlated color temperature, color rendering index (CRI), energy efficiency, and lifespan. Varieties of HID lamp include: 1 Mercury-vapor lamps 2 Metal-halide (MH) lamps 3 Ceramic MH lamps 4 Sodium-vapor lamps 5 Xenon short-arc lamps
Why is my HID lamp fading?
This shift is slight at first and is more generally a sign of the lamps being "broken in" whilst still being in good overall working order, but towards the end of its life, the HID lamp is often perceived as only producing blue and violet light. Based on Planck's law, this is a direct result of the increased voltage and higher temperature necessary to maintain the arc.
What happens when an arc is started?
Once the arc is started, it heats and evaporates the metallic admixture. Its presence in the arc plasma greatly increases the intensity of visible light produced by the arc for a given power input, as the metals have many emission spectral lines in the visible part of the spectrum. High-intensity discharge lamps are a type of arc lamp .
What is a high pressure sodium lamp?
High-pressure sodium lamps tend to produce a much whiter light, but still with a characteristic orange-pink cast. New color-corrected versions producing a whiter light are now available, but some efficiency is sacrificed for the improved color. Ballasts for discharge lamps. Like fluorescent lamps, HID lamps require a ballast to start ...
What is the wall load of a refractory arc tube?
The light-producing element of these lamp types is a well-stabilized arc discharge contained within a refractory envelope arc tube with wall loading in excess of 3 W/cm² (19.4 W/in²).
How does a discharge tube work?
When a voltage is applied to the two electrodes and the pressure of the gas in the tube is reduced, eventually a pressure is reached at which a current flows, and the gas glows.
What type of vapor discharge lamp which produces light by means of the flow of electricity through gases?
A flicker light bulb, flicker flame light bulb or flicker glow lamp is a gas-discharge lamp which produces light by ionizing a gas, usually neon mixed with helium and a small amount of nitrogen gas.
What kind of light uses both electric discharge and fluorescence?
The high-intensity discharge light bulbs and lamps are a family of gas-discharge arcs lamps which create light by sending an electrical discharge between two electrodes.
Discharge Lamp Working Principle
Discharge Lamp Example
- A xenon flash lamp generates a flashlight either in the range of 10-3 or 10-6and they are mainly employed for film and theatrical lights. Specifically, strong lamp versions called strobe lights can deliver a long period of flashes thus permitting the stroboscopic analysis of the motion. This is the example of a discharge lamp.
Advantages of Discharge Lamp
- These lamps provide an extended range of spectrum visibility
- The enhanced life period of operation
- These lamps are cost-effective
Disadvantages
- A few of the disadvantages of the discharge lampare: 1. They deliver minimal power factor 2. These devices need either transformers or in few situations’ starters are required because starting is somewhat difficult 3. To achieve completse brilliancy, these devices take extended time 4. These discharge lamps are implemented only in a single direction 5. Flickering in these lamps pr…
Applications of Discharge Lamp
- The most prominent usage of these discharge lamps are neon signs
- Discharge lamps are extensively effective in providing a high range of luminosity
- Implemented in many domestic and commercial applications
- Used in sodium lights those deliver orange spark which we observe on streetlights
Overview
Gas-discharge lamps are a family of artificial light sources that generate light by sending an electric discharge through an ionized gas, a plasma.
Typically, such lamps use a noble gas (argon, neon, krypton, and xenon) or a mixture of these gases. Some include additional substances, like mercury, sodium, and metal halides, which are vaporized during startup to become par…
History
The history of gas-discharge lamps began in 1675 when French astronomer Jean Picard observed that the empty space in his mercury barometer glowed as the mercury jiggled while he was carrying the barometer. Investigators, including Francis Hauksbee, tried to determine the cause of the phenomenon. Hauksbee first demonstrated a gas-discharge lamp in 1705. He showed that an evacuate…
Color
Each gas, depending on its atomic structure emits radiation of certain wavelengths, its emission spectrum, which determines the color of the light from the lamp. As a way of evaluating the ability of a light source to reproduce the colors of various objects being lit by the source, the International Commission on Illumination (CIE) introduced the color rendering index (CRI). Some gas-discharge lamps have a relatively low CRI, which means colors they illuminate appear substantially differe…
Types
Lamps are divided into families based on the pressure of gas, and whether or not the cathode is heated. Hot cathode lamps have electrodes that operate at a high temperature and are heated by the arc current in the lamp. The heat knocks electrons out of the electrodes by thermionic emission, which helps maintain the arc. In many types the electrodes consist of electrical filaments made of fine wi…
Other examples
The Xenon flash lamp produces a single flash of light in the millisecond-microsecond range and is commonly used in film, photography and theatrical lighting. Particularly robust versions of this lamp, known as strobe lights, can produce long sequences of flashes, allowing for the stroboscopic examination of motion. This has found use in the study of mechanical motion, in medicine and in the lighting of dance halls.
Alternatives
• Incandescent lamps. They have low manufacturing costs;
• White LED lamps. The efficiency of white LED lamps is 61-200 lm/W.
• Battery-powered lanterns (filling with krypton or xenon).
See also
• Electric arc
• Electric glow discharge
• Emission spectrum
• Fluorescent lamp
• Gas-filled tube
Further reading
• Waymouth, John (1971). Electric Discharge Lamps. Cambridge, MA: The M.I.T. Press. ISBN 978-0-262-23048-3.
• National Highway Traffic Safety Administration. "Glare from headlamps and other front mounted lamps". Federal Motor Vehicle Safety Standard No. 108. US Department of Transportation. Retrieved 2006-01-23.