- A Zener diode works in reverse breakdown and keeps the voltage constant, so it is used as a voltage regulator.
- A photodiode is reverse biased and produces current when light falls on it.
- An LED is forward-biased and emits light when electrons recombine with holes.
- A solar cell converts sunlight directly into electrical energy without external bias.
- Special diodes are used for specific purposes like voltage control, light emission, light detection, and solar energy conversion.
Definitions [6]
Definition: Depletion Region
When the junction is formed, majority carriers diffuse across the junction and recombine, creating a region without mobile charge carriers called the depletion region.
Definition: Potential Barrier
The potential difference developed across the depletion region is called the 'potential barrier' or barrier potential.
Definition: Forward Biasing
A p–n junction is said to be forward-biased when the positive terminal of the battery is connected to the p-region and the negative terminal to the n-region.
Definition: Reverse Biasing
A p–n junction is said to be reverse-biased when the positive terminal of the battery is connected to the n-region and the negative terminal to the p-region.
Definition: p-n Junction
A p–n junction is formed when p-type and n-type regions are joined in a single semiconductor crystal; the boundary is called the p–n junction.
Definition: Rectifier
A rectifier is a device which converts an alternating current (or voltage) into a direct (unidirectional) current (or voltage).
OR
The process of converting alternating current (voltage) into direct current (voltage) is called rectification. The device used is called a rectifier. Ap-n junction can act as a rectifier.
Formulae [1]
Formula: Electric Field in the Depletion Region
Ei = \[\frac {V}{d}\]
Key Points
Key Points: Diode as a Rectifier
- A half-wave rectifier uses one diode and converts only one half of AC into pulsating DC; its efficiency is about 40.6%.
- In half-wave rectification, a diode conducts under forward bias and blocks current under reverse bias.
- A full-wave rectifier uses two diodes (or bridge arrangement) and converts both halves of AC into pulsating DC; its efficiency is about 81.2%.
- A full-wave rectifier gives higher efficiency and smoother output (after filtering) than a half-wave rectifier.
Key Points: Types of Junction Diodes
