Various Light Sources and LED source Demo.pptx

Presentation for various Light Sources

1. Light Sources Aiswarya Dev Goswami B.E.E., M.E.E., Research Scholar (Thesis Submitted) AICTE Doctoral Fellow (ADF) Electrical Engineering Department Jadavpur University

2. Contents: Light Light Sources Natural Source of Light Artificial Source of Light Incandescent Lamp Mercury Vapor Lamp Low Pressure Sodium Vapor Lamp High Pressure Sodium Vapor Lamp Halogen Lamp Fluorescent Lamp LEDs

3. Light: Electromagnetic radiation that can be seen by the human eye is known as light or visible light. Typically, visible light is characterized as having wavelengths between 400 and 700 nanometers (nm), or frequencies between 750 and 420 terahertz, which fall between the (longer-wavelength) infrared and the (shorter-wavelength) ultraviolet. Light is made of packet of photon particles having the energy E = hʋ

4. Pictorial Representation:

5. Light Sources: Natural source of Light: SUN A fraction of the electromagnetic energy emitted by the sun, including infrared, visible, and ultraviolet light, is known as sunlight. When the Sun is above the horizon, sunlight on Earth is seen as daylight after being dispersed and filtered by the atmosphere. CCT: 5900K (above the atmosphere) CRI: 100 Luminous Efficacy: 105 lumen/watt

6. Seasonal Affective Disorder: A mood disorder characterized by depression that occurs at the same time every year. Seasonal affective disorder occurs in climates where there is less sunlight at certain times of the year. Symptoms include fatigue, depression, hopelessness and social withdrawal. Treatment includes light therapy (phototherapy), talk therapy and medication.

7. Artificial Light Sources: Incandescent Lamp: A wire filament is heated till it shines in an electric light called an incandescent lamp.   To prevent the filament from oxidizing, it is encased in a glass bulb with a vacuum or inert gas like Argon gas. Via terminals or wires concealed in the glass, current passes through the filament.

8. CCT: 2700K CRI: 100 Luminous Efficacy: 16 lm/watt Life: 1000 – 2000 Hrs. E27 Type

9. Mercury Vapor Lamp: A mercury-vapor lamp is a gas-discharge lamp that emits light by passing an electric arc through evaporated mercury. The arc discharge is often contained within a tiny fused quartz arc tube that is installed within a larger soda lime or borosilicate glass bulb.  The outer bulb may be transparent or coated with a phosphor; in any case, the outer bulb offers thermal insulation, safeguards against the UV radiation the light emits, and makes it easy to mount the fused quartz arc tube.

10. CCT: 5600K – 6400K CRI: 15 - 50 Luminous Efficacy: 35-55 lm/watt Life: 24000 Hrs.

11. Low Pressure Sodium Vapor Lamp: A sodium-vapor lamp is a type of gas discharge lamp that produces light with an average characteristic wavelength of 589.3 nm by using sodium in an excited state. Low-pressure sodium lamps are extremely effective electrical light sources, but because of their yellow light, they can only be used for outdoor illumination, like street lights, which is where they are most commonly found. In order to initiate the gas discharge in low-pressure sodium (LPS) lamps, a little amount of neon and argon gas in a Penning mixture is added to the gas discharge tube (arc tube) made of borosilicate glass. When the lamp is first started, it emits a dim red/pink light and also the process heats up the sodium metal; within a few minutes as the sodium metal vaporizes, the emission becomes the common bright yellow.

12. CCT: < 2000K CRI: 25 Luminous Efficacy: 150-200 lm/watt Life: 18000 Hrs.

13. High Pressure Sodium Vapor Lamp: High-pressure sodium (HPS) lamps are commonly utilized as plant grow lights and have been utilized extensively in industrial lighting, particularly in big manufacturing plants. They have also been frequently utilized for illuminating outside spaces, such as parking lots, streets, and security zones. They have mercury in them. Arc tubes are frequently built of transparent aluminum oxide due to the intense chemical reactivity of high-pressure sodium arcs. The HPS lamp uses xenon as its "starter gas" at low pressure.

14. CCT: 2100K CRI: 21 Luminous Efficacy: 100-150 lm/watt Life: 14000 Hrs.

15. Halogen Lamp: A halogen lamp is an incandescent lamp made of a tungsten filament enclosed in a tiny, transparent envelope that contains a small quantity of an inert gas and a halogen, such as iodine or bromine. The halogen gas and tungsten filament together create a chemical reaction known as a halogen regenerative cycle that deposits evaporated tungsten back onto the filament, extending its lifespan and preserving the envelope's clarity. This enables the filament to burn at a greater temperature than a typical incandescent lamp of comparable power and operational life; this also results in light that is more luminously effective and cooler in color. Halogen lamps' small size makes it possible for them to be used in tiny optical systems for projectors and lighting.

16. CCT: 3000K CRI: 100 Luminous Efficacy: 15-22 lm/watt Life: 2500 Hrs.

17. Halogen Regenerative Cycle: The tubular envelope in tungsten-halogen lamps is filled with an inert gas (either nitrogen, argon, krypton, or xenon) that is mixed during assembly with a minute amount of a halogen compound (usually hydrogen bromide; HBr ) and trace levels of molecular oxygen. The halogen compound serves to initiate a reversible chemical reaction with tungsten evaporated from the filament to yield gaseous tungsten oxyhalide molecules in the vapor phase. Thermal gradients formed as a result of the temperature differential between the hot filament and the cooler envelope contribute to interception and recycling of tungsten to the lamp filament through a phenomenon known as the halogen regenerative cycle. The benefits of the halogen regenerative cycle include the ability to use smaller envelopes that are maintained in a clean, deposit-free condition during the life span of the lamp.

18. Fluorescent Lamp: Fluorescent lamps, often known as fluorescent tubes, are low-pressure mercury-vapor gas discharge lamps that emit visible light by fluorescence. Mercury vapor is excited by an electric current in the gas to create short-wave ultraviolet light, which illuminates a phosphor coating within the lamp. Compared to an incandescent lamp, a fluorescent lamp is far more efficient in converting electrical energy into usable light. Another sub-variant of fluorescent lamp, called as compact fluorescent lamp or CFL is designed to replace incandescent lamps with the similar space requirement.

19. CFL CCT: 2700K-6500K CRI: 87 Luminous Efficacy: 50 - 100 lm/watt Life: 7000 - 15000 Hrs.

20. Light Emitting Diode (LED) Lamp: A LED is a solid-state semiconductor device that emits light upon the flow of electricity, following the principle of electroluminescence. Electroluminescence is the emission of light when electrons driven by an electrical or magnetic field enter a lower energy orbital and release the excess energy in the form of electromagnetic radiations. Sometimes a phosphor coating is used to produce complementary colors from a single LED. Some of the light from the LED is absorbed by the molecules of the phosphor, causing them to fluorescence, emitting light of another color.

21. CCT: Variable CRI: 90 Luminous Efficacy: 200 - 300 lm/watt Life: 50000 - 100000 Hrs.

22. Spectral Power Distribution Of Various Lamps:

23. Cntd…

24. Cntd…

25. Cntd…

26. Thank You