Today, in this blog I'm going to give you a thorough overview of different types of diodes. This blog is the continuous blog of the series of Diodes so if you wish to read about any other diodes or basics of diode then click here, we will discuss different types of diodes, their symbols, their characteristics, the applications of all diodes.
In electronics, different types of diodes are used for different applications. They are employed as voltage regulators, oscillators, switches, signal mixes, signal limiters, signal modulators, and demodulators, among other things. In this blog, I will explain the inner workings of many varieties of diodes.
Types of Diodes
P-N Junction Diode or Rectifier Diode
The P-N junction diode is made up of semiconductor material. It consists of two layers of semiconductors. One layer is doped with P-type material and the other layer with N-type material. The combination of these both P and N-type layers form a junction known as the P-N junction.
It allows the flow of current in the forward direction and blocks it in the reverse direction. They are also known as rectifier diodes used for rectification.
Applications Of PN Junction Diode
When converting AC to DC, General diodes are used.
Half Wave rectifier:
Full Wave Rectifier:
The input signal is converted to all positives, as shown in the picture below.
Diodes are used in clamping circuits.
A diode clipper is an electronic circuit that clips or cuts off an input signal using one or more diodes.
A light-emitting diode is referred to as an LED. If the LED is connected in forwarding bias, then current flows through the junction and generates light. When current is passed through a LED, photons are emitted due to which it glows.
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LEDs are fairly popular these days and may be found in most electronic devices. The cost has been reduced to the point that they are now employed in circuits to signify board-level functionality.
Applications Of LED
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LED bulbs are used in homes and industries.
- Used in electronic circuits to indicate power supplied
- Used in mobile phones to display messages.
- Used in traffic light signal.
- Used as bulbs in motorcycles and cars.
A Zener diode is a special type of diode which operates in the Zener breakdown region. In the breakdown area, zener’s have a much sharper current curve than normal diodes, it is used to provide a stable reference voltage. These diodes can work in forward as well as in reverse bias mode eg 1N4742A. It is heavily doped diode than the normal PN junction diodes.
It has a very thin depletion region, so it allows more electric current than the normal PN junction diodes. The Zener diode is used to protect the electronic circuit. Other applications of the Zener diode are it is used in voltage stabilizer and waveshaping.
Applications Of Zener Diode
| Zener diode as a voltage regulator |
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Zener diode in clipping circuits
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Use to protect overvoltage
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A Schottky diode is one in which the P-type material is removed and the N-type material is combined with a metal to form the diode because of which the forward voltage of a diode is decreased.
This Schottky diode has a lower forward voltage drop compared to ordinary silicon PN junction diodes. At low currents, the voltage drop may be between 0.15 and 0.4 volts. These are having high efficiency, low forward voltage drop, low capacitance, low profile surface mount Package. Along with the fact that they recover faster, makes them helpful in circuits such as switching power supply.
Applications Of Schottky Diode
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Schottky diode applied to dual power
- Used in RF mixer and Detector diode.
- Used in stand-alone photovoltaic systems to prevent batteries from discharging
- Used in rectifier application
- This can be used in voltage clamping applications
Avalanche Diode
Avalanche diode is a special type of semiconductor diode which operates in the avalanche breakdown region at a specified reverse-biased voltage. It is similar to the Zener diode but the doping level in the avalanche diode differs from the Zener diode.
It is made of silicon or other semiconductor materials. The avalanche diode is lightly dopped then the Zener diode so the width of the depletion region is wider than the Zener diode.
Avalanche diodes are used to protect the electrical system from excess voltage. so it is used as a relief valve that controls the pressure in the system. And also it is used as a white noise generator.
Some of the applications of an Avalanche Diode include:
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The Avalanche diode is used for the protection of the circuit. When reverse bias voltage increases then up to a certain limit diode starts an avalanche effect at a particular voltage and diode breakdown due to avalanche effect.
- It is used to protect the circuit against unwanted voltages
- It is used in surge protectors to protect the circuit from surge voltage
Gunn Diode
It differs from other diodes in that it is made entirely of N-type material (there is no P-type material in it).
It consists of three N-type layers; two of them which are on the terminal’s side have a higher doping concentration whereas the middle thin layer has a lighter doping concentration.
As the voltage across the device rises, the current rises until it reaches a point where it starts to fall.
They're often utilized in microwave electrons oscillator circuits, such as radar speed guns and automated door openers.
Applications Of Gunn Diode
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It is used as gun oscillators just to generate frequencies that range from 100mW 5GHz to 1W 35GHz.
- Used as sensors to detect trespassers.
- It is used as an efficient microwave generator.
- Used in, door opening sensors.
- It is used for remote vibration detectors.
The photodiode is a type of P-N junction diode that converts the light energy into an electrical current. Its operation is opposite to that of an LED. When photons are absorbed by a photodiode, electricity is generated. Typically, photodiodes operate under reverse bias conditions where even a small amount of flow of current resulting from the light can be simply noticed.
Every semiconductor diode is affected by optical charge carriers. That is why they are packaged in a light-blocking material.
In the photodiode, there is a special opening that allows the light to enter its sensitive part. When the light (Photon particles) strikes the PN junction, it creates an electron-hole pair. These electrons and holes flow out as electrical current.
In reality, every digital camera technology is based on an array of photodiodes, each of which is referred to as a pixel.
Applications of Photodiode
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Used in Fire Alarms
- Used in charge of a couple of devices.
- It is used in photomultiplier tubes.
- It is used to measure the intensity of light exactly.
- Widely used in numerous medical applications.
PIN Diode
PIN diodes are created by placing two undoped materials between two P-type and N-type materials.
The electron and holes from N and P-type regions respectively flow to the intrinsic region (I). Once the “I” region fills completely with electron-holes, the diode starts conduction.
In reverse bias, the wide intrinsic layer in the diode can block and tolerate high reverse voltages.
At a higher frequency, the PIN diode will act as a linear resistor. It is because the PIN diode has a poor reverse recovery time. The reason is that the heavily charged “I” region does not get enough time to discharge during fast cycles.
Applications Of Pin Diode
- Used as a high voltage rectifier.
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It is used as an ideal radiofrequency Switch.
Tunnel Diode
Tunnel diodes make use of a phenomenon known as quantum tunneling.
The interesting thing about these devices is that current travels easily from anode to cathode at first. The current flowing through the device reduces as the forward voltage rises, resulting in negative resistance.
Then, when the voltage drops even lower, it begins to behave like a typical diode. They're helpful in circuits like frequency converters and detectors.
A tunnel diode is a heavily doped PN junction diode that has negative resistance due to tunneling. The diode is used as a very fast switching device in computers and used as a logic storage memory device. and also it is used in high-frequency oscillators, amplifiers, and FM receivers.
The tunnel diode also conducts current in reverse direction & it is a fast switching device.
Applications Of Tunnel Diode
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It is used as a relaxation oscillator circuit.
The tunnel diode helps in generating a very high-frequency signal of nearly 10GHz. A practical tunnel diode circuit may consist of a resistor R2 and a supply source V, connected to a tank circuit(resistor Rp, capacitor, inductor) through a tunnel diode D.
- R1 sets proper biasing for the diode.
- R2 sets proper current level for the tank circuit.
- The parallel combination of resistor Rp inductor L and capacitor C form a tank circuit, which resonates at the selected frequency
- Used as an ultra-high-speed switch
- It is used as a logic memory storage device.
- Used as a microwave oscillator due to small capacitance and negative resist
Power Diode
A power diode is a type of diode that is commonly used in power electronics circuits. Just like a regular diode, a power diode has two terminals and conducts current in one direction. A power diode varies in construction from a standard diode to enable this higher current rating.
The ordinary signal diodes have a junction formed by p-type semiconductors and n-type semiconductors.
Power diodes are also similar to regular diodes, although they vary slightly in their construction.
Applications of Power Diode
- Power Diodes are used in high power applications such as three-phase rectifiers, inverters.
- Power diodes are used for power controllers, battery chargers, control panel power supplies, etc.
- Power diodes are used in snubber circuits, high voltage rectifications, etc.
If you wish to buy any of these diodes then you may click on their names present down.