The mercury in the tube is a liquid at normal temperatures. Fluorescent light problems and repair the family handyman. Actually fluorescent tube filled with mercury they emitt ultraviolet light if excited, which is provided by starter. The starter s purpose is to send a delayed jolt of ionized gas to the bulb to conduct electricity.
A fluorescent tube has a filament at each end, just like the filament in an incandescent bulb but very. The operating principle is simple, when current is applied, the gas inside. As the reader can surmise, the operation of a fluorescent light. Choke does two works first is to provide high initial. Ballast balance how fluorescent lamps work howstuffworks. Animation shows the circuit of the first kind of fluorescent lamp called the preheat. Anderson was a professor at rensselaer polytechnic institute and employee of general electric with 27 patents 1970 1992 related to lamp technology. Rk primer of school lighting lamps and maintenance. An electric current in the gas energizes mercury vapor which delivers ultraviolet radiation through discharge process and the ultraviolet radiation causes the phosphor coating of the lamp inner wall to radiate visible light. When the switch is on, full voltage will come across the tube light through ballast and fluorescent lamp starter. When the current is switched on, the starting mechanisms at each end of the lamp produce electrons that excite the gases.
It refers to that part of the circuit which limits the flow of current through the lighting device and may vary. The average life of tube lights is about 5000 hours and also. The ultraviolet light makes particles that coat the inside of the tube, and these particles glow or fluoresce. Low pressure mercury fluorescent lamps or tube lights. How starter of tube light works, connection circuit diagram youtube.
An electric current stimulates mercury atoms, which causes them to release ultraviolet photons. Youll find replacement starters at any hardware store. When voltage is applied to the fluorescent lamp, heres what happens. The tubes are coated on the inside with a fluorescent material, usually a compound containing phosphorous. At that full voltage first the glow discharge is established in the starter. How starter of tube light works, connection circuit. All credits and sources are located at the bottom of each lighting page. Fluorescent light fixture and tube troubleshooting and repair. The standard fluorescent lamp was developed for commercial use during the 1930s. Fluorescent lamps need a unlike an incandescent lamp, a fluorescent lamp cannot be operated on its own in ballast and sometimes a the circuit without some device to limit the current flow through it see lesson 7, starter as well section 3. The starter is a switch that is normally open, that closes a few seconds after power is applied. The idea of the fluorescent lamp had been around since the 1880s however it took steady work over the decades to finally create a working commercially viable model. Just remove one of the stillworking pair of fluorescent tubes and replace it with each of the questionable tubes, one at a time. Fluorescent tube lamp starter scr datasheet production data features high clamping voltage structure 1200to1500v low gate triggering current for direct drive from line 175 ma, ensuring high striking energy description the tn22 has been specifically developed for.
Other materials and gases are used to help start the lamp or control its color. Fluorescent starters are used in several types of fluorescent lights. The lamps use a tube which is curved or folded to fit into the space of an incandescent bulb, and a compact electronic ballast in the. The basic principles of the most commonly used lamp types. This article discusses the construction and working principle of low pressure mercury fluorescent lamps also known as tube lights. In addition to this device, which is termed a ballast, most types need a starter as. If it is a 2 pin lamp, the starter is actually included inside the lamp body.
The tube contains argon gas at a low pressure of 2. The lamp works by creating an electric arc through vaporized sodium metal. How compact fluorescent lamp cfl works working principle. The basic construction of a cfl consists a tube which is curvedspiraled to fit into the space of an incandescent bulb, and a compact electronic ballast in the base of the lamp. The starter is made up of a discharbe bulb with two electrodes next to it.
Anderson developed many improvements in the fluorescent lamp. What is the importance of starter and choke in fluorescent. When the lamp first turns on, the gas is resistant to electricity. If the fitting has a traditional magnetic ballast and a four pin lamp, there will be a starter included too. Glow starter also known as the starter, is a sealed unit filled with inert gas and consists of 2 parts, a capacitor and a bimetallic contact. Operation of preheat type fluorescent lamp the tube filaments, starter glow switch, and ballast are all in series, which constitute a complete circuit once the switch, is closed. Some basic facts and some advanced information on ballasts. The tube also contains a phosphor powder, coated along the inside of the glass. One of the methods is using a starter switch and a magnetic ballast to provide the flow of ac current to the lamp. A fluorescent lamp basically consists of a long glass gas discharge tube. A compact fluorescent lamp cfl, also called compact fluorescent light, energysaving light and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent light bulb.
A flickering fluorescent bulb means that it or one of a dependent pair of bulbs in the fixture has bought the. The working principle is the same in both types of luminaires. Fluorescent lamps are made of a glass tube filled with a low pressure mixture of gases, specifically mercury and noble gases like argon, neon, xenon and krypton. Then we connect the fluorescent tube and a starter across it. It needs to be vaporized and ionized before the tube will conduct electricity and the arc can start. A cfl uses vacuum pipe which is principle wise same to the strip lamps commonly known as tube light. The starters purpose is to send a delayed jolt of ionized gas to the bulb to conduct electricity.
If the fluorescent lamp has a magnetic or wirewound ballast you will also need to replace the starter canister. What makes the fluorescent tube fundamentally so efficient is the extremely high efficiency with which it is able to convert electrical energy into this uv radiation. The choke will be connected in series and one end of both the filament will connected to the starter. You can see how this system works in the diagram below. Some manufacturers, supply a ballast compatibility table. A fluorescent starter is a small, metallic cylinder that plugs into a socket of a fluorescent fixture.
This emitted ultraviolet light is converted into visible light as it strikes the fluorescent coating as well as into heat when absorbed by other materials. The tube contains a small bit of mercury and a gas usually argon kept under very low pressure. Starters, however, tend to very rugged and can cycle many times before they fail. Some older fluorescent fixtures and those under 20 watts often require starters, which are the small aluminum or plastic cans in a socket near one end of the lamp. Electronic ballast is a device which controls the starting voltage and the operating currents of lighting devices built on the principle of electrical gas discharge. What is the working principle of mercury vapour lamp answers. Commercially it is available in 10, 20, 40 and 80 watts. How a fluorescent light works schematic animation youtube. If your fluorescent lamp has an electronic ballast, you only need to swap the lamps.
The low pressure mercury fluorescent lamps are commonly called as tube lights. The starter is made up of a discharge bulb with two electrodes next to it. Capacitor and bimetallic contact inside the starter. A fluorescent lamp or fluorescent tube is a gasdischarge lamp that uses electricity to excite.
See how the ballast and starting switch work to strike an arc. Conventional lamp ballast the simplest form of ballast is an inductor. The operating principle is simple, when current is applied, the gas inside ionizes and heats a bimetallic strip which in turn bends toward the stationary electrode thus shorting the starter between the. It is commonly filled with neon gas or argon gas and contains a bimetallic strip and a stationary electrode. The starter which is simply a timed switch allows current to flow through the filaments at the ends of the tube. In the fluorescent lamp the luminous section of the gas column is artificially very much extended. Electronic fluorescent lamp ballast stmicroelectronics. Since the fluorescent power is used in the tube, it is called as fluorescent tube. If the fixture has more than one lamp that isnt working, it is unlikely that all lamps and starters failed at the same time, so check the other causes. Generally fluorescent material absorbs uv radiation and then illuminates. The filaments light up and instantly warm up the tube. If the fitting is high frequency, it will always have a 4 pin lamp.
Fluorescent tube lamp starter scr stmicroelectronics. Only a tiny proportion of visible light is radiated by the low pressure mercury discharge, this being predominately at the wavelengths of 405nm violet, 436nm blue, 546nm. As a current flow through, the gas inert inside the starter glows and the electrodes are heated. This is because the electrodes gap in the neon bulb of starter is much lesser than that of the fluorescent lamp.
If the fixture contains a single lamp, try replacing the lamp and the starter. The fluorescent light has a longer wavelength than the light it absorbs. Fluorescent lamps are electric discharge light sources where an arc is struck in a lowpressure, gasfilled tube. Firstly, they are very much more efficient than glow lamps, so they produce much more light for less power consumption. When an ac voltage is applied to a tube light fixture, the voltage passes through the choke, the starter, and the filaments of the tube.
Brief working principle of fluorcent tubelight,function of. The starter is a small neon glow up lamp that contains a fixed contact, a bimetallic strip and a small capacitor. I explain, how starter of tube light works, use of glow starter with connection circuit diagram, voltage and current waveforms in this video. Figure 1 shows a driving circuit for a fluorescent lamp operated from the 220240v mains. A 4 pin is essentially a bend fluorescent tube imaging two mins from each end. Fluorescent lamp starter switch 1 june 1984 revised september 2002 specifications are subject to change without notice. Older fluorescent light fixtures that flicker or only light up part way may just need a new starter, which is a less expensive repair than a bulb. Then gas inside the starter gets ionized due to this full voltage and heats the bimetallic strip. Compact fluorescent lamp working principle the electrons that are bound to mercury atoms are excited to states where they will radiate ultraviolet light as they return to a lower energy level. Therefore it has lower energy than the absorbed radiation.
A fluorescent lamp is a low weight mercury vapour lamp that uses fluorescence to deliver visible light. It has electrodes at either end and works by sending current through a gas between those electrodes. What is the importance of starter and choke in fluorescent lamp. Start it up how fluorescent lamps work howstuffworks. Fluorescent lamp and working principle of fluorescent lamp. A glow switch starter is a type of preheat starter used with fluorescent lamp.
They are available in lengths from the very small of 150 mm to up to 2400mm. Before you can understand how condensers work in fluorescent lamps, you need to know a few things about the lamps themselves. The arc is sustained between two filaments by regulating the current through the lamp, using a ballast. When we switch on the supply, full voltage comes across the lamp and as well as. A fluorescent tube is filled with a gas containing low pressure mercury vapors and any other noble gas. These photons in turn stimulate a phosphor, which emits visible light photons. A defective starter can cause the bulb to flicker continuously or leave you in total darkness. The starter switch is required to preheat the lamp so that considerable less amount of voltage is required to trigger the production of electrons from the electrodes of the lamp.
In most vacuum lamps, an active material known as a getter is applied to the filament or leads during manufacture to reduce residual gas pressure and to clear up the atmosphere when the. The light itself is ultraviolet and therefore invisible but causes the fluorescent layer inside the tube to shine. For your easy understanding, i will first describe the main light and how it works. The starter is located on the lamp frame there are typically two starters. The current causes the starters contacts to heat up and open, thus interrupting the flow of current.
However, not all led tubes are suitable for all hf ballasts. The working principle of fluorescent lamp is quite complicated but not difficult to understand, and i found it very interesting. Ansi code american national standards institute ansi code that indicates the electrical operating designation of the lamp, which must match that of the ballast. General design the general design of a simple fluorescent lamp consists of a sealed glass tube. Lifetime of fluorescent lamps operating with electronic. Its inner surface is coated with phosphorous and is filled with an inert gas, generally argon, with a trace of mercury. Fluorescent lamps come in all shapes and sizes, but they all work on the same basic principle. This principle of the choke is exploited in lighting a fluorescent tube light. Induction lamps are a form of fluorescent lamps but they dont have electrodes. When the lamp first turns on, the path of least resistance is through the. What is fluorescent lamp the fluorescent tube consists of a glass tube 25mm in diameter and 0.
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