Visible LEDs and invisible LEDs are two classes of light emitting diodes. The wavelength or color of emitting light depends on the forbidden gap or energy gap of the materials.
Types of LED :
- Gallium Phosphide (GaP) – red, yellow and green
- Aluminium Gallium Phosphide (AlGaP) – green
- Gallium Nitride (GaN) – green, emerald green
- Gallium Arsenide (GaAs) – infrared
- Gallium Arsenide Phosphide (GaAsP) – red to infrared, orange
- Aluminium Gallium Arsenide Phosphide (AlGaAsP) – high-brightness red, orange-red, orange, and yellow
- Gallium Indium Nitride (GaInN) – near ultraviolet, bluish-green and blue
- Silicon Carbide (SiC) – blue as a substrate
- Zinc Selenide (ZnSe) – blue
Applications of LED :
- Picture phones and digital watches
- Camera flashes and automotive heat lamps
- Aviation lighting
- Digital computers and calculators
- Traffic signals and Burglar alarms systems
- Microprocessors and multiplexers
Advantages of LED :
- LEDs operate very fast.
- These can emit different colors of light.
- LEDs do not contain toxic material like mercury which is used in fluorescent lamps.
- Brightness of LED can be easily controlled by varying the current.
- These are smaller in size, light in weight and have longer in lifetime.
- These are very cheap, readily available and consume low energy.
Disadvantages of LED :
- LEDs are efficiency is low and need more power to operate than normal p-n junction diodes.
Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.