Diode is a semiconductor device, which consists of two semiconductor layers. Rectifier diode and LED (Light Emitting Diode) are two types of diodes used in different type of applications. LED is a special type of diode which has the capability to emit light, which cannot be found in normal diodes. Designers select them according the requirement of the application
Rectifier Diode
Diode is the simplest semiconductor device and it consists of two semiconductor layers (one P-type and one N-type) connected to each other. Therefore diode is a PN junction. Diode has two terminals known as the anode (the P-type layer) and cathode (the N-type layer).
Diode allows current to flow through it only in one direction, that is from anode to cathode. This direction of current is marked on its symbol as an arrow head. Since diode restricts the current to flow only one direction, it can be used as a rectifier. The full bridge rectifier circuit, which is made of four diodes can rectify an alternative current (AC) to a direct current (DC).
The diode starts acting as a conductor when a small voltage is applied in the direction of anode to cathode. This voltage drop (known as the forward voltage drop) is always there when a current flow happens. This voltage is usually about 0.7V for normal silicon diodes.
LED (Light Emitting Diode)
LED is also a type of diode that can emit light when conducting. Since diode consists of P-type and N-type semiconductor layers, both ‘electrons’ and ‘holes’ (positive current carriers) take part in conduction. Therefore, the ‘recombination’ process (a negative electrons joins a positive hole) happens, releasing some energy. LED is made in a way that, those energies are released in terms of photons (light particles) of preferred colors.
Therefore LED is a light source, and it has many advantages such as energy efficiency, durability, smaller size etc. Currently environment friendly LED light sources have been developed and they are also used in modern displays.
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What is the difference between Rectifier Diode and LED 1. LED emits light when conducting, whereas rectifier diode doesn’t emit. 2. LEDs are often used as light sources, and rectifier diodes are used in rectifying applications. 3. Materials used in rectifier diodes and LED’s have different properties.
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