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Which of the following materials is used in light-emitting diodes?

Which of the following materials is used in light-emitting diodes? Correct Answer Gallium arsenide phosphide

The LED (light-emitting diode) is a PN junction device that emits light when a current passes through it in the forward direction.

Materials used:

Semiconductor materials used for the manufacture of LED are gallium arsenide phosphide (GaAsP) which emits red or yellow light or gallium arsenide (GaAs) which gives green or red-light emission.

Applications:

LEDs are used extensively in segmental and dot matrix displays of numeric and alphanumeric characteristics. Several LEDs are used in series to form one segment while a single LED may be used as a decimal point.

Advantages:

Size: LEDs are miniature in size and they can be stacked together to form numeric and alphanumeric displays in a high-density matrix.

Controlling the output: The light output from an LED is a function of the current flowing through it. Therefore, the intensity of light emitted from LEDs can be smoothly controlled.

Efficiency: LEDs have high efficiency as emitters of electromagnetic radiation.

Available colors: LEDs are available in different colors like red, green, yellow, and amber.

Switching time: The switching time of both ON and OFF is less than 1 ns and therefore they are very useful where the dynamic operation of a large number of arrays is involved.

Economical and Reliable: LEDs are manufactured with the same type of technology as is used for transistors and ICs and therefore they are economical and have a high degree of reliability.

Operating temperature: LEDs are rugged and can, therefore, withstand shocks and vibrations. They can be operated over a wide range of temperature 0 to 70°.

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