Electric Discharge Lamp – Definition, Types, Advantages, Disadvantages & Applications
- Electric Discharge Lamps. A lighting device consisting of a transparent container within which a gas is energized by applying an electric voltage and thereby made to glow is known as ...
- Types of Electric Discharge Lamps. ...
- Advantages of Electric Discharge Lamps. ...
- Disadvantage of Electric Discharge Lamps. ...
- Applications of Electric Discharge Lamps. ...
Full Answer
How does an electric discharge produce light?
There is enough energy in an electrical discharge to excite air or other gasses ionizing molecules and causing electrons to change orbits and produce photons - light! The high current heats up the air to the point that it fluoresces.
What are two examples of an electric discharge?
Electric discharge denotes the excitation of atomic states in a gaseous medium on passing an electric current through the medium. An ordinary household fluorescent lamp is an example of an electric-discharge source. The lamp tube, coated on the inside with fluorescent phosphors, contains a mixture of a rare gas and mercury vapour.
What does electric discharge mean?
Electric discharge is the process in which a region of high electric potential, having an excess of charge, relative to another region of lower electrical potential, having less charge than the former region, reorganize themselves so that each region has the same electrical potential, or the same amount of electrical
What is the definition of electric discharge?
Definition. An electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas. Several types of electric discharges occur naturally on Earth (American Geophysical Union, 1986): 1.
What is discharge lamp used for?
High pressure discharge lamps Applications include indoor lighting of high buildings, parking lots, shops, sport terrains. High pressure mercury-vapor lamps are the oldest high pressure lamp type and have been replaced in most applications by metal halide and the high pressure sodium lamps.
What is called discharge lamp?
electric discharge lamp, also called Vapour Lamp, lighting device consisting of a transparent container within which a gas is energized by an applied voltage and thereby made to glow.
Is LED lamp a discharge lamp?
The new lighting fixtures which use power LED have a light spectrum much better than that of discharge lamps, they can therefore be used in any environment that requires even colour temperatures next to the solar spectrum and they have a high luminous efficiency (the White LEDs can reach an efficiency of 300 lumens / ...
What is the most common type of electric discharge lamp?
incandescent lamps that contain a reflector coating to give the lamps a more directed light output. Most common type of electric discharge lamp, and are characterized by a longer lifetime of 7,000 to 20,000 hours. highly efficient light sources, that have long life and a high lumen over their lifetimes.
What are examples of electric discharge?
Electric discharge is defined as the excitation of atomic states in a gaseous medium when an electric current passes through the medium. An example of electric discharge is fluorescent lamp.
What is disadvantage of discharge lamp?
(i) High initial cost and poor power factor. (ii) Starting is somewhat complicated requiring starters in some cases and transformer in others. (iii) These take time to attain full brilliancy. (iv) Ballasts are necessary for stabilising the current since such lamps have negative resistance characteristic.
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.
Which of the following lamp is not a discharge lamp?
Incandescent Lamp is a filament type lamp. An incandescent lamp essentially consists of a fine wire of a high-resistance metal placed in an evacuated glass bulb and heated to luminosity by the passage of current through it. Since all power dissipated in it in terms of I2R heating, hence it works on unity power factor.
What are the differences between incandescent and gas discharge lamps?
While fluorescent (CFL) bulbs generate light by sending an electrical discharge through an ionized gas, incandescent bulbs emit light by heating the filament present in the bulb.
Which lamp is used in outdoor games?
A floodlight is a broad-beamed, high-intensity artificial light. They are often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions.
Why ballast is required for discharge lamp operation?
In a fluorescent lighting system, the ballast regulates the current to the lamps and provides sufficient voltage to start the lamps. Without a ballast to limit its current, a fluorescent lamp connected directly to a high voltage power source would rapidly and uncontrollably increase its current draw.
What kind of an electric discharge lamp in which the major portion of then radiation is produced by the excitation of mercury atoms?
A mercury-vapor lamp is a gas-discharge lamp that uses an electric arc through vaporized mercury to produce light.
What is 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.
How does a discharge lamp work?
The Discharge lamps are one of the reliable sources of artificial light energy, which fundamentally works by converting electrical energy to light energy by ionizing the gas particles. Discharge lamp gained popularity, in the mid-twentieth century. The best part of the discharge lamps, it can produce lights of different colors.
How does a ballast work in low pressure lamps?
The low-pressure discharge lamps require the ballast to create a high voltage. Ballasts fundamentally work on the principle of inductance. The voltage across the inductor is directly proportional to the product of inductance and the rate of change of current (di/dt). With increase.
What is mercury lamp?
We shall see the high-intensity discharge lamps for this case. The mercury lamps are mostly used for street lighting due to their long span of life. They provide about 50 lumens per watt. They also provide huge energy savings while usage. The metal halide lamps are mostly used for indoor purposes like stadiums, outdoor areas, sports facilities, etc.
What is the advantage of low pressure discharge?
In low-pressure discharge lamps, the working pressure is much less than the atmospheric pressure. Like the fluorescent lamps, and the sodium lamps. They produce 200 lumens per watt. One advantage of low-pressure discharge is they have a long life span. The low-pressure discharge lamps require the ballast to create a high voltage. Ballasts fundamentally work on the principle of inductance. The voltage across the inductor is directly proportional to the product of inductance and the rate of change of current (di/dt). With increase.
How long does it take for a high intensity lamp to reach peak voltage?
The ballast helps to build up the high voltage. For this reason, when turned on, the high-intensity lamps take up to ten minutes to reach peak value. The high-pressure mercury vapor lamp, metal halide lamps, and high-pressure sodium lamps are some of the examples of high-intensity lamps.
What is high intensity discharge?
High-intensity Discharge. The high-intensity discharge lamps are very efficient as compared to pressure based discharge lamps. They have a long life span and can save a lot amount of energy. The high-intensity lamps use an arc array to produce intense light.
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.
When was the discharge lamp invented?
Francis initially showed a discharge lamp in the year 1705. He demonstrated that either emptied or partially emptied glass globe where he placed a few drops of mercury, as charged by the static current might generate luminous light. This scenario was later known that it is the principle of the discharge lamp. ...
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.
What is the pressure of a sodium lamp?
For instance, an enhanced pressure level sodium lamp operates at a range of 100-200 torr which means 15-30 percent of the atmospheric pressure level. Some of the types of high-pressure discharge lamps are:
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.
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 electromagnetic radiation?
This electromagnetic radiation is based on the gas, vapor present in the metal, and the pressure that is in the lamp. In general, sodium, mercury vapors, and argon gas are used for the development of discharge lamps. Discharge Lamp Example. When the isolation process has initiated in the gas, it holds the tendency to enhance constantly resulting in ...
What is the best known 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 is discharge tube?
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. Typically, such lamps are filled with a noble gas (argon, neon, krypton and xenon) or a mixture of these gases. Most lamps are filled with additional materials, such as mercury, sodium, and metal halides. When the gas is ionised, free electrons are accelerated by the electrical field in the tube and collide with gas and metal atoms. Some electrons in the atomic orbital of these atoms are excited by these collisions to a higher energy state. When the excited atom falls back to a lower energy state, it emits a photon of a characteristic energy, resulting in infrared, visible light, or ultraviolet radiation. Some lamps convert the ultraviolet radiation to visible light with a fluorescent coating on the inside of the lamp’s glass surface. 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.
How do HID lamps work?
HID lamps produce light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. Compared to other lamp types, relatively high arc power is applied in these lamps. HID lamps may be one of the following types: 1. Mercury vapour lamps.
What is sodium vapour lamp?
The sodium vapour lamp uses sodium in an excited state to produce light. There are two varieties of such lamps: low-pressure sodium (LPS) and high pressure.
What is a CDM lamp?
The ceramic discharge metal (CDM) halide lamp, or ceramic metal halide (CMH) lamp, is a relatively new source of light and is an improved version of the high-mercury vapour lamp.
What is the activator for a fluorescent lamp?
For the daylight fluorescent lamp, magnesium tungstate is used as phosphor, which emits light at 480 nm. Calcium halophosphate as phosphor and antimony/manganese as activator are used in cool-white fluorescent lamps lacking red light and in modified redder warm-white fluorescent lamp.
How long does a halogen lamp last?
The luminous efficacy of an HID lamp is over three times that of a halogen lamp and its life is about 2000 hours, compared to 300–700 hours for a halogen lamp.
How does a discharge tube work?
A gas- discharge tube is a glass tube with a couple of wires in it. 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 is a discharge lamp used for?
It is possible to maintain luminosity for an extended period with discharge lamps. Their applications range from domestic to commercial areas and are affected by the type of gas being used.
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.
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).
What is a cold cathode lamp?
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. A compact fluorescent lamp.
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.
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