Incandescent Lamp
- Principle: Light is produced by heating a tungsten filament until it glows.
- Features: Warm light, low efficiency, short lifespan.
- Applications: Household lighting, decorative lamps.
Arc Lamps (AC & DC)
- Principle: Electric arc between two carbon electrodes.
- AC Arc Lamp: Operates on alternating current, flickers slightly.
- DC Arc Lamp: Operates on direct current, with a steadier light.
- Applications: Projectors, searchlights, industrial lighting.
Fluorescent Lamp
- Principle: Electric discharge excites mercury vapour → UV radiation → phosphor coating emits visible light.
- Features: Higher efficiency, cooler light, longer life.
- Applications: Offices, schools, commercial spaces.
Other Lamps
- Mercury Vapour Lamp: High intensity, bluish light.
- HPMV Lamp (High Pressure Mercury Vapour): Improved efficiency, used in street lighting.
- Mercury Iodide Lamp: Produces bright white light, used in photography.
- Ultraviolet Lamps: Emit UV radiation, used for sterilisation and medical purposes.
- Neon Sign Tubes: Glow in bright colours, used for advertising.
- Metal Halide Lamps: High efficiency, good colour rendering, used in stadiums and malls.
- HID (High Intensity Discharge) & Arc Lamps: Very bright, used in automotive headlights and industrial lighting.
- LED Lamps: Semiconductor-based, highly efficient, long lifespan, available in many voltages.
- CFL (Compact Fluorescent Lamp): Mini fluorescent lamp, energy-saving alternative to incandescent.
- Lasers: Produce coherent, monochromatic light; used in medical, industrial, and communication fields.
Selection Criteria for Lamps
- Efficiency: Lumens per watt.
- Colour Rendering: Naturalness of light.
- Lifespan: Durability and maintenance cost.
- Application Needs: Indoor, outdoor, decorative, industrial.
- Cost & Availability: Balance between initial cost and long-term savings.
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