Diode Types and Applications

In this article we will learn about diodes, like what is diode, how it works and most importantly why do we need this?

Why do we need this?

A diode is an electronic component that allows current to flow in only one direction. It is used in a variety of electrical and electronic circuits to protect against voltage spikes, rectify alternating current (AC) to direct current (DC), and as a switch. Additionally, diodes can also be used in signal processing and power conversion. In short, diodes are used to control the flow of electrical current in a circuit and protect other electronic components from damage.

Diodes are everywhere, There are chargers, mobile phones, toys, laptops etc.

  • Rectification: A diode can be used to convert AC voltage into DC voltage by allowing current to flow in only one direction. For example, a bridge rectifier circuit uses four diodes to convert AC voltage from a wall outlet into DC voltage that can be used to power electronic devices.
  • Voltage regulation: Diodes can be used to maintain a constant voltage level in electronic circuits. For example, a Zener diode can be used to regulate voltage by operating in the reverse breakdown region and maintaining a constant voltage across its terminals, even when the input voltage changes.
  • Protection circuits: Diodes can be used to protect electronic components from voltage spikes and other transient events. For example, a TVS (Transient Voltage Suppression) diode can be used to protect sensitive electronic components from voltage spikes caused by lightning or electrostatic discharge.
  • Logic gates: Diodes can be used to implement logic gates in digital circuits. For example, an AND gate can be implemented using diodes by connecting two diodes in series with two inputs, and connecting the junction of the diodes to the output.
  • LED lighting: A Light Emitting Diode (LED) is a diode that emits light when current flows through it in the forward direction. LEDs are commonly used in lighting applications, such as in traffic signals and electronic displays.

Overall, diodes are versatile electronic components that are used in a wide range of applications, from basic rectification to complex digital circuits.

History

The diode was invented in 1904 by Sir John Ambrose Fleming as a detector for radio signals. The first semiconductor diodes were developed in the 1920s, and were used in radio receivers. The development of the transistor in the 1940s led to the development of the first semiconductor rectifiers in the 1950s.

What is Diode?

A diode is an electronic component that allows electricity to flow in one direction only. It is used to prevent a circuit from being damaged by reverse currents, which can happen when the circuit is connected to a power source with a different polarity. Diodes can also be used to create a voltage drop or to limit the voltage or current in a circuit.

How Does Diode Work?

The behavior of a diode depends on the direction of current flow through it, which can be forward biased or reverse biased.

Forward Bias

When a diode is forward biased, the P-type material is connected to the positive terminal of a voltage source, and the N-type material is connected to the negative terminal. In this configuration, the voltage applied to the diode causes the free electrons in the N-type material to move towards the positive terminal, while the holes in the P-type material move towards the negative terminal. As a result, a current flows through the diode from the P-type material to the N-type material.

In a forward-biased diode, the depletion region between the P-type and N-type materials is reduced, allowing the current to flow easily. The voltage at which the diode begins to conduct is called the forward voltage drop, which is typically around 0.7 volts for silicon diodes and 0.3 volts for germanium diodes.

Reverse Bias

When a diode is reverse biased, the P-type material is connected to the negative terminal of a voltage source, and the N-type material is connected to the positive terminal. In this configuration, the voltage applied to the diode causes the free electrons in the N-type material to move away from the positive terminal, while the holes in the P-type material move away from the negative terminal. As a result, the depletion region between the P-type and N-type materials widens, and no current flows through the diode.

In a reverse-biased diode, the depletion region acts as an insulator, preventing current from flowing. However, if the reverse bias voltage is increased beyond a certain point, called the breakdown voltage, the depletion region breaks down and allows current to flow in the reverse direction. This effect is used in Zener diodes and avalanche diodes, which are designed to operate in the reverse breakdown region and maintain a constant voltage across their terminals.

Application

Diode is the basic building block of an electronic device or circuit.

  • Used in zener diode
  • Transistor
  • Amplifier
  • LED
  • Rectifier circuit
  • Multivibrator
  • Timer circuit
  • Wave shaping circuit
  • As a switch
  • In the modulation process as modulator.
  • Radio demodulation (AM)
  • Power conversion (AC to DC)
  • Over-voltage protection 
  • Logic gates 
  • Temperature measuring 
  • Current steering

There are countless uses and applications of diodes. Overall, diodes are versatile electronic components that are used in a wide range of applications, from basic rectification to complex digital circuits.