Difference Between P-N Junction Diode and Zener Diode

Knowledgebase

The main difference between a P-N junction diode and a Zener diode is that P-N junction diodes allow current to flow in one direction, while Zener diodes are designed to allow the flow of current in both directions. This means that when a voltage is applied across a P-N junction diode, it will become forward-biased and allow current to pass through it. On the other hand, when a voltage is applied across a Zener diode, it will become reverse-biased and allow current to pass through in both directions.

P-N Junction Diode VS Zener Diode

What Is A PN Junction Diode?

-P-N junction diodes are semiconductor devices where a single crystal of semiconductor material is divided into two parts, the P-type and N-type, creating a barrier between them. The p side consists of positively charged particles (holes) and the n side consists of negatively charged particles (electrons). When a voltage is applied to the diode, the electrons and holes will move toward each other and create a current flow.

What Is A Zener Diode?

-A Zener diode is also a semiconductor device, but unlike the P-N junction diode, it is designed to allow current to pass through in both directions. This is done by applying a reverse voltage across the diode, which allows electrons to move from the p side of the diode to the n side. This creates a large number of electron-hole pairs, which can be used to conduct current in both directions. The amount of voltage that needs to be applied to the diode is known as the Zener voltage.

What Is The SI Unit Of Zener Diode?

The SI unit of the Zener diode is the volt (V).

What Is The SI Unit Of the P-N Junction  Diode?

The SI unit of the P-N junction diode is the ampere (A).

How Does It Work?

PN junction diode:

  • A PN junction diode consists of a p-type semiconductor material, with positive charge carriers, and an n-type semiconductor material, with negative charge carriers.
  • In this type of diode, the two materials are connected together to form a single structure.
  • When forward biased (that is when the voltage applied across the junction is in the forward direction), the electrons from the n-type material move to the p-type material, and holes from the p-type move to the n-type.
  • This creates a region of positive charge near the P side of the diode, and a region of negative charge near N side.
  • Thus, the current flow is only possible in the forward direction.
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Zener Diode:

  • Zener diodes are special types of P-N junction diodes that can operate in the reverse-bias mode.
  • When a voltage is applied across the Zener diode, it will become reverse biased and allow current to pass through it until the breakdown voltage is reached.
  • Once the breakdown voltage is reached, the Zener diode will become forward-biased, allowing current to pass through it and providing a relatively constant voltage output. This behavior makes Zener diodes ideal for regulating voltages in circuits.
  • Unlike regular P-N junction diodes, which are only designed to handle a certain amount of current and voltage, Zener diodes can handle large amounts of both without breaking down. This makes them a much more reliable component for voltage regulation.

What Is The Purpose Of A Pn Junction Diode?

The purpose of a PN junction diode is to control the flow of current in an electronic circuit. It acts as a one-way valve, allowing current to pass in one direction but not in the other. It can also be used as a voltage regulator or rectifier.

What Is The Purpose Of A Zener Diode?

A Zener diode is used as a voltage regulator in circuits because it has the ability to maintain a constant output voltage regardless of changes in input current. It is also able to withstand large amounts of power without breaking down, making it highly reliable and efficient.

Applications:

PN Junction diode:

  • Rectifiers
  • Switching elements
  • voltage multipliers

Zener Diode:

  • Voltage regulator in circuits.
  • voltage stabilizers

Pros And Cons:

PN Junction Diode:

  • Pros: Easy to manufacture, inexpensive, and low power consumption.
  • Cons: Wide variances in output voltages due to temperature fluctuations.

Zener Diode:

  • Pros: Highly reliable and efficient, can handle high current and voltage, unaffected by temperature changes.
  • Cons: Expensive and difficult to manufacture.

Difference Between P-N Junction Diode And Zener Diode

PROPERTY PN Junction Diode Zener Diode
Doping level of p-type & n-type semiconductors: Moderately doped Highly doped
Direction of applied voltage: Forward bias only Reverse bias and forward bias
Ability to handle current & voltages: Limited High
Breakdown voltage: No breakdown voltage Has a breakdown voltage
Use case: Used for rectification and as switching elements in circuits Used for voltage regulation in circuits.
Symbol: Symbol shows an arrowhead pointing towards the P-region of the diode. Symbol shows an arrowhead pointing towards a line from P to N region of the diode.
Width of depletion layer: Narrow width Wide width.
Type of current flow: Breakdown Bidirectional
Biasing condition: Forward bias Reverse and forward bias.
Ohm’s law: Follows Ohm’s law Not strictly follows Ohm’s law.
Construction: Two P-N junction are connected in series. Combination of highly doped N and P-type semiconductor material with a thin layer of lightly doped material in between them.
working principle: Electron flow from N-type to P-type material under forward bias. In reverse bias conditions, the electric field in the Zener diode is so high that electrons break free from their covalent bonds and move across the junction and thus allow current to pass through it.
Output Voltage: Variable output voltage. Constant output voltage.
Effect of temperature : Affects its characteristics severely. Not affected significantly by temperature changes.
Manufacturing materials: Made using elements from the third or fourth row of the periodic table. Made using elements from the fifth and sixth row of the periodic table.
Current flow: Unidirectional current flow. Bidirectional current flow.
Behave in forward & reverse bias:  Acts as an open switch when no voltage is applied, and a closed switch when voltage is applied in the forward direction.  Acts as a closed switch when no voltage is applied and allows current to pass through it in both forward and reverse bias.
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FAQs

What Does The Temperature Coefficient Imply?

The temperature coefficient of a PN junction diode denotes how its characteristics are influenced by changes in temperature. Generally, as the temperature increases, the output voltage of the diode decreases. Zener diodes don’t exhibit any significant changes in their characteristics with changes in temperature.

What Is The Purpose Of A Zener Diode As A Voltage Regulator?

A Zener diode is used as a voltage regulator in circuits because it has the ability to maintain a constant output voltage regardless of changes in input current.

What Does It Mean When A Zener Gets Broken Down?

When a Zener diode gets broken down, it means that the electric field in the diode is too strong and electrons are able to move freely across the junction, causing current to flow through it.

Explain The Differences Between P-Type And N-Type Semiconductors.

  1. P-type semiconductor materials are made up of positively charged holes, while N-type semiconductors are composed of negatively charged electrons.
  2. P-type materials tend to have higher electrical conductivity than N-type materials.
  3. In a circuit, P-type material is used for current flow in one direction and N-type material is used for current flow in the opposite direction.
  4. When P and N type materials are joined together, a PN junction diode is formed.

Explain The Meaning Of The Term “Doping” And Why It Is Necessary.

Doping is the process of introducing impurity atoms into a semiconductor material, usually in order to increase its conductivity. Doping is necessary because it allows for current flow to be possible through the PN junction diode. Without doping, the two materials would not be able to interact and no current would be able to pass through.

Why Does A P-N Junction’S Depletion Zone Produce An Electric Field?

The depletion zone of a p-n junction produces an electric field because the positively charged holes and negatively charged electrons are separated by this region. This creates an imbalance in the electric charges, resulting in an electrostatic force that causes current to flow.

How Many Pn Junctions Are In The Zener Diode?

A Zener diode is composed of two PN junctions connected in series, with a heavily doped region in between. This allows for current to flow both ways through the diode, creating a voltage regulator.

What Are The Advantages And Disadvantages Of Using Zener Diode?

  • Advantages: Highly reliable and efficient, can handle high current and voltage, unaffected by temperature changes.
  • Disadvantages: Expensive and difficult to manufacture.

What Is the Difference Between Diode And Junction?

  1. Diodes are two-terminal PN junction devices in which current can flow in only one direction, while junctions refer to any type of connection between two components.
  2. Diodes are used for rectifying AC power, while junctions can be used to connect and integrate multiple electrical components together.

Is Zener Diode Ac Or Dc?

Zener diodes can be used for both AC and DC circuits. When used in an AC circuit, the diode will regulate and stabilize the output voltage regardless of any fluctuations in the input current. Similarly, when used in a DC circuit, the Zener diode will maintain a constant DC voltage by conducting current only when it reaches or exceeds a certain threshold.

What Are 2 Names For A Zener Diode?

A Zener diode is also sometimes referred to as a breakdown diode or avalanche diode.

Is Zener Diode Active Or Passive?

A Zener diode is a semiconductor device, and therefore it is considered to be an active component.

Why Zener Diode Is Used In Rectifier?

Zener diodes are used in rectifiers because they can regulate the output voltage and ensure that it remains constant regardless of changes in the input current.

What Are The 3 Diode Models?

  1. The Shockley diode model
  2. The ideal diode model
  3. The practical diode model

What Are The Three Main Types Of Diodes?

The three main types of diodes are:

  1. PN junction diode
  2. Schottky diode
  3. Zener diode.

Is A TVS A Zener?

TVS stands for Transient Voltage Suppressor, and it is not a type of Zener diode. TVS diodes are used to protect circuits from high-voltage transients, while Zener diodes provide a regulated voltage output in order to stabilize the power supply of a circuit.

Do Zener Diodes Limit Current?

Yes, Zener diodes do limit current. The breakdown voltage of a Zener diode is the point where it will start conducting current, and any voltage above this threshold will cause more current to flow through the diode in order to keep the output voltage constant.

Conclusion

P-N Junction Diodes and Zener Diodes have several differences. PN Junction Diodes are unidirectional, meaning that current is able to flow in only one direction. Zener Diodes are bi-directional and can handle higher voltages and currents than standard PN junction diodes. They also have a more reliable response to temperature changes compared to the latter. It is important to understand the differences between these two diodes in order to correctly use them in any circuit.

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