4Lamps?? A lamp is an energy converter. It also carries out secondary functions, its prime purpose is the transformation of electrical energy into visible electromagnetic radiation.There are many ways to create light. The standard method for creating general lighting is the conversion of some form of energy into light.
7Evidences of first lamp dates back to 70000 BC. Oil lamps were used mostly until the end of the 18th century.In the 19th century, the kerosene lamps were introduced in Germany.From early 19th century, most of the cities in the Europe and United States have their streets lit with gas light.In 1801 Sir Humphrey Davy invented the first electric carbon arc lamp , connecting two wires to the battery and attaching a charcoal strip to the other end of the wires making charge carbon glow.
8Lamps-types!!!!Various developments have been witnessed by the human kind in field of lamps.Today they are classified as below:Incandescent lamps.Halogen lamp.Fluorescent lamp.LED lamp.Arc lamp.Discharge lamp.Hydrogen lamps.
9Incandescent lampThese lamps use a tungsten filament in an inert gas or vacuum with a glass envelope.The inert gas suppresses tungsten evaporation and lessens the envelope blackening.The tungsten filament is a compact light source, easily focused by reflectors or lenses.Incandescent lamps are simple to dim by reducing the supply voltage, and are still used where dimming is a desired control feature.
10Incandescent Lamp…: Usage !!! Incandescent lamps are used popularly for domestic lighting because of their low cost and compact sizeDue to a large variety of lamp shapes, which are largely decorative in appearance. They are also used in decorative purpose.These lamps are also available with a wide range of colours and finishes.
12Halogen LampThese are similar to incandescent lamps and produce light in the same manner from a tungsten filament.However the bulb contains halogen gas (bromine or iodine) which is active in controlling tungsten evaporation.Fundamental to the halogen cycle is a minimum bulb wall temperature of 250 °C to ensure that the tungsten halide remains in a gaseous state and does not condense on the bulb wall.The bulbs are made from quartz in place of glass. With quartz it is possible to reduce the bulb size
13Halogen Lamp…: Usage !!!Tungsten halogen lamps have become popular where small size and high performance are the main requirement Typical examples are stage lighting, including film and TV, where directional control and dimming are common requirements.These are mainly designed for slide and film projectors.
15Fluorescent lampA fluorescent lamp or fluorescent tube is a low pressure mercury vapour gas discharge lamp that uses fluorescence to produce visible light.An electric current in the gas excites mercury vapour which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the bulb to fluoresce, producing visible light. They contain mercury, many fluorescent lamps are classified as hazardous waste.
16Fluorescent Lamp…: Usage!!! The compact fluorescent lamp (CFL) is becoming more popular in household usage.Fluorescent lamps are mostly found in kitchens, basements, or garages.Special fluorescent lights are often used in stage lighting for film and video production, as they are cooler compared to traditional halogen sources.
18LED lampA LED lamp is a light-emitting diode (LED) product that is assembled into a lamp (or light bulb) for use in lighting fixtures.LED lamps have a lifespan and electrical efficiency several times better than incandescent lamps, most fluorescent lamps, with some chips able to emit more than 100 lumens per watt.LEDs do not emit light in all directions. The light output of single LEDs is less that that of incandescent and compact fluorescent lamps; in most applications multiple LEDs are used to form a lamp.LED chips need controlled direct current(DC) electrical power; an appropriate power supply is needed. LEDs are adversely affected by high temperature, so LED lamps typically include heat dissipation elements such as heat sinks and cooling fins.
19LED Lamp…: Usage!!!These are used in flashlights, solar-powered garden or walkway lights, and bicycle lights.Monochromatic (colored) LED lamps are now commercially used for traffic signal lamp, and in strings of holiday lights.The use in street lights has also increased since 2010.
21Arc lamp“Arc lamp" or "arc light" is the general term for a class of lamps that produce light by an electric arc. The lamp consists of two electrodes, first made from carbon but typically made today of tungsten, which are separated by a gas.The type of lamp is often named by the gas contained in the bulb;viz. neon, argon, xenon, krypton, sodium, metal halide, and mercury etc.
22Arc Lamp…: Usage!!!Arc lamps are used in applications requiring great brightness, as in searchlights, large film projectors, and floodlights.Sir Humphry Davy constructed the first arc lamp (1807), using a battery of 2,000 cells to create a 100-millimetre (4-inch) arc between two charcoal sticks.When suitable electric generators became available in the late 1870s, the practical use of arc lamps beganThey are used for street lighting in various parts of the world from 1878.
24Discharge lampDischarge lamps are a family of artificial light sources that generate light by sending an electrical discharge through an ionized gas, a plasma.Such lamps use a noble gas (argon, neon, krypton and xenon) or a mixture of these gases.In operation the gas is ionized, and free electrons, accelerated by the electrical field in the tube, collide with gas and metal atoms.Some electrons in the atomic orbitals of these atoms are excited by these collisions to a higher energy state. When the excited atom falls back to a lower energ state, it emits a photon of a characteristic energy, resulting in infrared, visible light, or ultraviolet radiation.
25Discharge lamp…: Usage!!! These lamps are used in many places where incandescent lamps are used.These discharge sources create much more light from electricity compared to in candescent lamps.
26Hydrogen LampWhen an electric current is passed through a glass tube that contains hydrogen gas at low pressure the tube gives off blue light.Then this light is passed through a prism, four narrow bands of bright light are observed against a black background.A hydrogen discharge tube is a slim tube containing hydrogen gas at low pressure with an electrode at each end. If you put a high voltage across this (say, 5000 volts), the tube lights up with a bright pink glow.