Related Terminologies

Table of Contents

Zener Diode: Applications and Basis of Operation


Table of Contents

A Zener diode is a silicon semiconductor gadget that licenses current to stream in one or the other a forward or switch course. The diode comprises of an exceptional, vigorously doped p-n intersection, intended to lead in the converse course when a specific determined voltage is reached.

It is a clearly defined reverse-breakdown voltage at which it begins to conduct current and can continue to function continuously in reverse-bias mode without becoming damaged.

Operation of the Zener diode When connected in the reverse mode, which is typical for the majority of its applications, it may experience a small leakage current. However, when connected in the forward-bias mode, the Zener diode functions just like a standard diode with a turn-on voltage of between 0.3 and 0.7 V. A current begins to flow through the diode as the reverse voltage reaches the predetermined breakdown voltage (Vz). The series resistor determines when the current reaches its maximum, at which point it stabilizes and remains constant over a wide voltage range.

Zener Diode and its application.

The Zener diode is made from heavily doped silicon, so that the depletion layer is very thin.

Zener breakdown

The breakdown is either because of the Zener breakdown impact that happens beneath 5.5 V, or effect ionization that happens above 5.5 V. The two components bring about a similar way of behaving and don’t need different hardware; However, the temperature coefficient of each mechanism varies.

While the impact effect has a positive coefficient, the Zener effect has a negative temperature coefficient. The two temperature impacts are practically equivalent at 5.5 V and counteract each other to make the Zener diodes evaluated at around 5.5 V the most steady over an extensive variety of temperature conditions.

Zener breakdown voltage

Is breakdown voltage positive or negative?

Breakdown Voltage

If a large enough negative voltage is applied to the diode, it will give in and allow current to flow in the reverse direction. This large negative voltage is called the breakdown voltage.


Why breakdown occurs?

Breakdown occurs when the electric field becomes strong enough to pull electrons from the molecules of the material, ionizing them. The released electrons are accelerated by the field and strike other atoms, creating more free electrons and ions in a chain reaction, flooding the material with charged particles.

What is the use of Zener diode?

It is widely used as voltage references and as shunt regulators to regulate the voltage across small circuits. When connected in parallel with a variable voltage source so that it is reverse biased, a Zener diode conducts when the voltage reaches the diode’s reverse breakdown voltage.

What is symbol of Zener diode?

This voltage breakdown voltage, also known as the Zener voltage, is denoted by the symbol Vz.

What is the difference between diode and Zener diode?

Diodes are normally used for rectification, whereas Zener diodes are used for voltage regulation.

What is the working principle of Zener diode?

The working principle is such that if the reverse bias voltage is less than the breakdown voltage, or if it is forward biased then it acts as an ordinary diode. This means that forward bias allows current to flow and reverse bias blocks the current from flowing.

What is an example of Zener?

Therefore a zener diode is sometimes called a Voltage-regulator diode. For example, the output of half-wave, full-wave or bridge rectifiers consists of ripples superimposed on a DC voltage. By connecting a simple zener diode across the output of the rectifier, we can obtain a more stable DC output voltage.

What are the two types of Zener diode?

The principle behind the operation of a Zener diode is determined by the cause of the diode’s breakdown in the reverse bias condition. There are typically two types – Zener and avalanche.

Which devices use Zener diode?

Zener diode is used in clipping circuits

These kinds of circuits are generally used in TV and FM transmitters to remove interference.

What is difference between PN junction and Zener diode?

To conclude, the major difference between a PN junction diode and a Zener diode is that a PN junction diode allows the electric current to pass in only one direction (or forward direction), while a Zener diode allows the electric current to flow in both forward and reverse directions.

Is Zener Diode used in Electric Vehicle?

Zener diodes are used in the cooling fan drive of the Electric Vehicle battery management system. The increase in the use of Electric Vehicles boosts the Zener diode Market.

How many pn junctions are in a Zener diode?

There are many two-terminal devices, which have a single P-N junction. Zener diode is one of such two-terminal devices.

Zener diode applications:

Applications for zener diodes Zener diodes are used for voltage regulation, as reference elements, as surge suppressors, and in clipper circuits and switching applications.

Regulator of the voltage The diode’s breakdown voltage, VZ, is the load voltage. When the diode is conducting, the excess voltage is reduced and the diode’s current is restricted by the series resistor.

diode's breakdown voltage

Zener diode in overvoltage protection Zener diode in shunt regulator If the input voltage rises above the Zener breakdown voltage, current flows through the diode, resulting in a voltage drop across the resistor; This causes a short circuit to the ground and activates the SCR. The short out opens up the wire and separates the heap from the stock.

What is the maximum current of Zener diode?

The maximum current is calculated by dividing the power rating by the Zener voltage: I=P/V = 3W/12V = 0.25A.

Zener voltage and its symbol.

What is the minimum voltage of Zener?

A Zener diode voltage regulator has load requirement of 16 V and 2 Amp. The diode’s minimum current requirement is 2.5 A. The minimum voltage at input is 29 V.

Which current is used in Zener diode?

Zener/Breakdown Voltage – The Zener or the reverse breakdown voltage ranges from 2.4 V to 200 V, sometimes it can go up to 1 kV while the maximum for the surface-mounted device is 47 V. Current Iz (max) – It is the maximum current at the rated Zener Voltage (Vz – 200μA to 200 A)

What is the main use of Zener diode?

Uses of Zener diode : Used as voltage references and as shunt regulators to regulate the voltage across small circuits. In this way zener diodes are used as voltage regulator. These are also used as peak clippers, in switching operations and in meter protection applications.

Why Zener diode is used in reverse bias?

The Zener Diode is used in its “reverse bias”. Current starts to flow through the diode to limit this increase in voltage. Therefore the Zener diode will drain the current through it which is called a regulator. Thus, the Zener diode shows the voltage handling capacity.

Zener diode is used in reverse bias

Does Zener diode regulate AC or DC?

During the reverse biased condition, if the voltage across the Zener diode is greater than the breakdown voltage, then the Zener diode conducts. This breakdown voltage is known as the Zener breakdown voltage. The Zener diode is used as the main component in the dc power supply for voltage regulation.



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