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What are Uses & Applications of Diode?

A Brief List of Applications of Diode with Details

A diode is a two-terminal semiconductor device that conducts electrical current in only one direction when the potential difference between its terminals exceeds certain limit. Diodes are the most used devices in any electronics devices & their applications are unlimited which depends on the types of the diodes.

In this article, we will discuss the applications of diodes (including different types of diodes)

What are Uses & Applications of Diode

Applications of Diodes include

Following are some of the diode’s application used our daily life:

  • Rectification
  • As a Switch
  • Source Isolation
  • As Voltage Reference
  • Frequency Mixer
  • AM Envelope Detector or Demodulator (Diode Detector)
  • As a Light Source
  • As a Temperature Sensor
  • As a Light Sensor
  • A Solar Cell or Photo-Voltaic Cell
  • As a Clipper
  • As a Clamper
  • Protection against Reverse Current
  • Protection against Reverse Polarity
  • Protection against Surges

Also Read : Thyristor | Its Working, Types & Applications

1) Rectification

The diodes were first used for the rectification purposes to convert the AC signal into a unidirectional DC signal (pure audio signal) in radios or in power supplies etc. The diodes are used in mainly two types of rectifications;

Half Wave Rectification

The conversion of only half-wave of the AC signal into DC signal is called half-wave rectification. Such type of rectification is achieved by using only one diode but at the cost of losing half of signal.

Diode as Half Wave Rectifier

Full Wave Rectification

The full-wave rectifier converts the full wave of the AC signal into DC signal. it is made up four diodes in a specific configuration known as a bridge rectifier.

Diode as Full Wave Rectifier

It can convert the full wave of the AC signal into DC signal.

2) As a Switch (in Logic Gates)

The diode acts as a switch that turns on in forward bias & turns off in reverse bias. It is used in RDL (resistor diode logic) logic. Although this design is not used in modern circuits but you can easily design the basic logic gates using diode & resistors.

Diode as Digital Logic Switch

3) Source Isolation

An optocoupler or optoisolator is a device made from an LED (IR diode or LASER diode) & a photosensor to transfer the signal between two circuits. There is no electrical connection between the source circuit & the controlled circuit. Thus it isolates the source from high voltages.

4) As Voltage Reference

The Zener diode is used as a voltage reference in various electronics circuit to provide a stable voltage for biasing. It operates as a voltage regulator in reverse bias & provides a stable voltage over a wide range of current.

Diode as Voltage Reference

5) Frequency Mixer

A frequency mixer is a circuit that provides a new signal whose frequency is the sum or difference of the two input signals. The diodes are used in frequency mixer to shift the frequency of a signal such as in modulating a signal for transmission or demodulation in the superheterodyne receiver.

6) AM Envelope Detector or Demodulator (Diode Detector)

A Diode with a capacitor is the simplest & cheapest circuit used for the demodulation of the AM signal. The audio message signal is stored in the envelope of the AM modulated signal which is detected by the diode because it only allows the positive half cycle of the signal.

Diode Detector

7) Diode as Light Source

The diode such as LED (light-emitting diode) or Laser diode converts the electrical energy into light energy. The LED provides a diverged light while the laser diode provides a beam of converged light. The LEDs are used in lighting system such as flashes etc. while the laser diode is used in optical communication, pointers, printers & scanner etc.

Also Read : How To Test A Diode & Methods Of Diode, LED & Zener Diode Test

8) As a Sensor

The diode can be used as a sensor for temperature & light.

As a Temperature Sensor

According to the Shockley equation, the forward current of the diode depends on the temperature. In fact, if the forward voltage remains constant, the increase in the temperature decreases the forward current. It can be used to sense the temperature.

Peltier or thermal diode is used for heat monitoring in microprocessors.

As a Light Sensor

A photodiode is a light-sensing diode that converts light energy into electrical energy. It is designed with an exposed junction with an opening for light. When the photon particle hits its junction, it releases an electron-hole pair that creates a potential across its terminals.

They are used in optical communications, smoke detectors, IR detectors.

9) A Solar Cell or Photo-Voltaic Cell

The photovoltaic cell used in the solar panels converts solar energy into electrical energy. The difference between the photodiode & photovoltaic cell is that the photodiode needs reverse bias connection while the photovoltaic cell does not need any biasing.

Also Read: How To Test A Capacitor? Using Various Methods

10) As a Clipper

A clipper is a circuit made of diodes that is used to shape the signal waveform by clipping or cutting either a portion of positive half or negative or both halves of the signal. it is used for limiting the voltage at a predetermined point.

Diode as Clipper

11) As a Clamper

A clamper is a circuit that adds a positive or negative DC value shift to the signal without distorting it shape. The peak-to-peak value of the signal remains the same. The clamper is made up of a diode with a capacitor.

Diode as Clamper

12) Circuit Protection

Diodes are also used for protection purposes in a circuit for many reasons.

Protection against Reverse Current

A protection diode is used in a circuit to prevent the reverse current flow that could cause damage to the source or the components inside the circuit.

Protection against Reverse Polarity

A diode is used for protection against reverse polarity in a circuit. The reverse polarity of a battery can cause damage to the circuit’s components. Thus a diode which allows the current flow in only one direction is used to stop the current flow in such cases.

Protection against Surges

Special type of diodes known as TVS (transient voltage suppression) diode is used for suppression against high voltage surges. These diodes do not conduct under normal conditions but it prevents the damage to the components by grounding the high voltage spikes.

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