P N Junction Diode vs Zener Diode: Difference and Comparison

Our world changed with the discovery of electricity, we get our word done easily, and that gives us more time to think and invent new things. Many electrical and electronic devices around us come into existence in a few periods after electricity.

Similarly, diodes are a small but very important part of every piece of electronic equipment that most people are unaware of. There are many types of diodes, like PN junction Diode and Zener Diode.

Key Takeaways

  1. A P-N junction diode is a semiconductor device that conducts current in only one direction. In contrast, a Zener diode is a special P-N junction diode that allows current to flow in both directions and regulates the voltage.
  2. P-N junction diodes are used in various electronic devices, including rectifiers, oscillators, and amplifiers, while Zener diodes are often used in voltage regulation and protection circuits.
  3. P-N junction diodes and Zener diodes have different characteristics and applications, and their selection depends on the specific needs of the designed electronic circuit.

P N Junction Diode vs Zener Diode

A P-N Junction diode is a device which allows the current to flow in only one direction. When the current flows in the opposite direction in the PN junction diode, it causes damage. The semiconductors used in the manufacturing of pn junction diodes are silicon or germanium. Zener diodes allow the flow of current in both directions. In a Zener diode, the direction of the current can be forward or reversed.

P N Junction Diode vs Zener Diode

PN junction diode is like a simple diode that allows the flow of electrons only in one direction. It is generally made using semiconductors like silicon or germanium. In this diode, layer P of the semiconductor is joined to the N layer of the semiconductor using the alloying method. It is used as a rectifier, voltage multiplier, etc.


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In contrast, the Zener diode is a diode that allows the flow of current in both forward and reversed directions. It is made using semiconductors like silicon.

It has highly doped junctions. The breakdown voltage for Zener diodes is comparatively lower, and it is known as Zener voltage. It is generally used as a voltage stabilizer.

Comparison Table

Parameters of ComparisonP N Junction DiodeZener Diode
Definition It is a type of diode that allows the flow of current in one direction only.It is a type of diode that allows the flow of current in both directions.
Doping LevelIt is not highly doped as it allows current only in forward breakdown condition.It is a highly doped diode, as it is also used in reverse bias conditions.
Breakdown Voltage The breakdown voltage is comparatively higher.The breakdown voltage is comparatively lower.
Ohms LawIt obeys Ohms Law.It does not obey Ohms Law.
Application It is used as voltage rectifiers.It is used as voltage stabilizers.

What is P N Junction Diode?

PN junction diode is a type of diode that allows the flow of current in one direction only. It does not resist the current while it is going in the forward direction, but when the current comes backwards, it increases its resistance, stopping the current from going in the opposite direction.

It is made of semiconductors like silicon and germanium. The layer P of the semiconductor is put on the N-layer semiconductor to make a PN junction diode.

In the first layer of the semiconductor, holes are the main carrier, whereas electrons are the main carrier in the second layer of the semiconductor.

Both layers are not just connected using a simple coupling method, but it uses a very much complicated technological process. As there are more electrons in the N layer, hence after connection, there is a diffusion of holes and electrons.

Electrons move from the N layer to P, and holes move from layer P to N to make equal concentration on both sides.

The PN junction diode is represented using a diagram. In that diagram, there is an arrowhead known as an anode and a bar on it known as a cathode.

All these things are represented in a straight line. It has various uses and applications in electronic equipment. It is used as a rectifier, voltage multipliers, waveshapers, etc.

p n junction diode

What is Zener Diode?

Zener diode is listed as a special type of diode that allows the flow of electrons in both directions. It has a highly doped p and n junction.

It allows the current to flow backwards when the voltage crosses a certain value. This certain value is known as breakdown voltage or Zener voltage.

The Zener effect was discovered in 1934 by American physicist Clarence Zener when he was studying the voltage breakdown in insulator properties.

Hence this Zener effect was named after him, and the Zener diode works on the Zener effect. It tells about the breakdown voltage of the diode, which is comparatively low in this diode and known as Zener voltage.

It is generally made of silicon, and the concentration of ions is more in the material of the diode.

Whenever the current is passed from this diode, the depletion layer between the junction reduces, and due to this, the electric field concentration increases.

An increase in voltage leads to ions of electrons going towards the depletion region to make it conductive.

It has its application in various electronic equipment and is an essential part of electrical circuits.

It is used at places where voltages vary as it can provide a constant voltage to the load. Hence it is used surge protector and voltage stabilizer.

zener diode

Main Differences Between P N Junction Diode and Zener Diode

  1. The main difference between the PN junction diode and the Zener diode is that the PN junction diode allows the flow of electrons in one direction only, whereas the Zener diode allows the flow of electrons in both directions.
  2. The voltage of the PN junction diode at which it starts working is comparatively higher, and the voltage of the Zener diode at which it starts working is lower, and it is known as Zener voltage.
  3. The PN junction diode is not highly doped. On the other hand, the Zener diode has highly doped junctions.
  4. On applying a large reverse bias voltage, the PN junction diode has a chance of getting damaged, but the Zener diode is specialized for this case.
  5. PN junction diode is used as a voltage rectifier, switcher, waveshaper, etc., whereas Zener diode is used as voltage stabilizers.
Difference Between P N Junction Diode and Zener Diode
  1. https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.200306185
  2. https://www.cambridge.org/core/journals/mrs-online-proceedings-library-archive/article/study-of-zener-diodes-by-semdvc/88F7CB35265416463D397AD438FF1816

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