Difference between a Normal diode and a Zener diode: Explained

In this blog, we will discuss the “difference between a normal diode and a Zener diode”. There are many differences between a diode and a zener diode.

Although both the diode and the zener diode belong to the diode family, they are used for different applications.

Table of contents:

Difference between a normal Diode and a Zener diode: Functional

What is a Diode?

A diode is a two-terminal semiconductor device. It allows the current to flow in only one direction.

The current flows in the diode during forward bias.

It blocks the current during reverse bias. However, a very small leakage current can still flow.

Applications of diodes

Main applications of the diode are as follows:

• Since current flows only in one direction, we use it for rectification, as in AC-to-DC conversion.
• It is also used to block reverse voltage.
• Other applications of diodes are in clamping.
• They can also be used to double the peak voltage of the AC voltage. to be useful in generating high voltage for testing.
• It is also used in IGBT based rectifier.

Further applications of the diode:

• Many diodes can be connected in series for higher voltage applications with proper design.
• It can also be used for blocking reverse current in DC circuits.
• Also used to limit reverse voltage in the DC power supply of IC circuits.
• Making a simple “OR” gate
• Input voltage protection in operational amplifier circuits.

What is a Zener diode? explained

A Zener diode is a special type of diode designed to operate in reverse voltage.

If we apply a reverse voltage across the zener diode, then it allows current to flow once the voltage reaches the Zener breakdown voltage (Vz).

Applications of the Zener diode

The main applications of the Zener diodes are:

• Voltage regulators
• Overvoltage protection for electronics
• Voltage reference circuits in electronics, like in comparator circuits.
• Protection of integrated circuits
• Blocking the OP amp from going into saturation
• Surge protection of limited energy

Difference between a normal diode and a Zener diode – Comparison chart

Functions	Diode	Zener Diode
Current and Volatge Characterstics	Allows current to flow in one direction only. and block voltage in the reverse direction	Allows current in one direction and regulates voltage in reverse voltage bias
Voltage Regulation	No	Yes, maintains a constant voltage across it
Reverse Volatge	Yes, but it may be damaged if more voltage is applied.	Current will flow if reverse voltage is applied. A resistor is seried required to limit the current
Signal or power type	Signal and power didoe, both types are available	Signal and power Zener diode, both types are available
Symbol	See fig 1	See fig 1
Applications	IGBT Rectifier, bridge, Rectifiers, signal, clamping, doubling the AC voltage peak in the surge generator, for reverse current protection in inductor circuits.	Voltage regulation, voltage reference, protection to the Op amp input, and limiting the output voltage of the OP Amp

Questions and Answers

Question: Are a diode and a zener diode the same?

Answer: No, they are different function-wise.

Question: Can I apply reverse voltage across a diode?

Answer: Yes, but within the limit of the diode

Question: Can diodes be connected in parallel to increase current?

Answer: Yes, but the current will not be doubled. Derating in the current required.

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I hope you enjoyed reading the article on the “difference between a normal diode and a Zener diode”.

Further read, the current transformer with an open circuit.

Also, read AC or DC, which is more dangerous.

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