Diodes (Image, Definition)

A diode is a two-terminal electronic component that conducts current primarily in one direction; it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the opposite direction. Here are the key aspects of diodes:

Basic Function: #

The most fundamental property of a diode is to allow current to flow in one direction (forward direction) while blocking it in the reverse direction. This is achieved through the use of semiconductor materials, such as silicon or germanium, which are doped to create a p-n junction with distinct positive (anode) and negative (cathode) sides.

Types of Diodes: #

There are several types of diodes, each designed for specific functions:

• Rectifier Diodes: Common diodes used for converting alternating current (AC) to direct current (DC).
• LEDs (Light Emitting Diodes): Emit light when current flows through them in the forward direction.
• Zener Diodes: Allow current to flow in the reverse direction when the voltage exceeds a certain value, used for voltage regulation.
• Schottky Diodes: Known for their low forward voltage drop and fast switching speed.
• Photodiodes: Generate a current or voltage when exposed to light.

Applications: #

• Rectification: In power supplies to convert AC to DC.
• Voltage Regulation: Zener diodes maintain a stable voltage across electronic components.
• Signal Mixing and Detection: In radio and audio equipment.
• Lighting: LEDs for displays, indicators, and lighting.
• Protection: Diodes are used in circuits to protect against reverse polarity or voltage spikes.

Characteristics: #

• Forward Voltage Drop (V_F): When forward-biased (positive to the anode and negative to the cathode), a diode requires a certain minimum voltage before it will conduct, typically around 0.7 volts for a silicon diode and 0.3 volts for a Schottky diode.
• Reverse Breakdown Voltage (V_R): The maximum reverse voltage a diode can withstand before it starts conducting in reverse, which is particularly high in Zener diodes designed for this purpose.

Diodes are fundamental components in electronic circuits, with their ability to control the direction of current flow being exploited in a wide variety of ways to achieve different functionalities.