Zener diode, operation and applications!

Do you know what a diode is and how it works? Do you know the Zener diode, its characteristics, how it works and its applications? In this article, the World of Electrical explains what is a diode, what are the main types of diodes and especially what is a ze

Do you know what a diode is and how it works? Do you know the Zener diode, its characteristics, how it works and its applications? In this article, the World of Electrical explains what is a diode, what are the main types of diodes and especially what is a Zener diode, besides mentioning how a Zener diode works, what are the characteristics and applications of the Zener diode. Come on!

You may never have heard of the diodes, but it is very likely that you have seen diodes, since all LED panels, monitors and lamps are actually a type of diode, which is the Light Emitting Diode, popularly known as LED ( Light Emitter Diode).

Diode – What is it?

The diode is basically an electronic component that allows the passage of electric current in only one direction, according to its polarization. A simple analogy that we can make is to compare a diode to a valve that only lets water flow in one direction, that is, the diode does the same thing with the electric current, as we can see in the image below.

Diodes are like valves, allowing the passage of electric current in a single direction.

Nothing in the electronics is ideal, so to make a diode conduct electricity you need to supply it with a voltage of at least 0.7V between anode and cathode, considering silicon diodes, that is, less than that the diode is not capable of a drive.

The diodes can perform specific functions such as capacity varies depending on the voltage, voltage regulator, light emission, such as varicap, Zener and lead respectively. In addition to these diodes that have been mentioned, we can mention other types of diodes with specific characteristics such as, for example, Schottky diode, photodiode, Gunn diodes and tunnel diode. In the image below we can see the diode symbologies that were mentioned.

Description and symbologies for different types of diodes.

Zener Diode

The zener diode, also known as voltage regulator diode, is named after the American physicist Clarence Melvin Zener, he was the first to describe that the breaking mechanism of electrical insulators is a type of diode, which unlike most applications for the diodes, which operate in the conduction region, the Zener always operates reverse polarized.

Zener diode – Operation

Therefore, in order for us to understand how the Zener diode works, we need to understand its characteristic curve, as we can see in the image below:

The part that interests us to understand the operation of the Zener diode is located in the fourth quadrant of the graph above, where we find the cut and avalanche region of a diode, which is where the diode is reversedly polarized.

As we can see, while the reverse voltage is lower than the rupture voltage, nothing different happens, characterizing a conventional diode, but when the reverse voltage approaches a value that depends on the diode being analyzed, this diode conducts and electrical current passes through it, and this current is only limited by the value of external resistances.

In this situation, even if the reverse voltage at the diode tries to be raised above the Zener voltage value, this is not possible. However, if the current increases too much, the power dissipation in the diode will increase, causing the device to reach its point of destruction, mainly due to the joule effect.

The zener diode, operating in reverse, maintains the value of the maximum voltage between its terminals at a constant value, called the voltage of the zener diode, however, if the Zener diode is directly polarized it will behave like a common rectifier diode.

Zener Diode – Features and Applications

Comparing the zener diode with the common diode, we can conclude that the zener diode is manufactured precisely to work with reverse polarization, thus, when the rupture voltage of the zener diode is reached it becomes practically constant regardless of the current passing by the diode.

When working as a zener diode, we must take into account some parameters such as its regulating voltage, minimum current and maximum operating current.

The regulating voltage of the zener diode is the voltage that will remain practically constant for as long as the diode is in operation.

The minimum current is the minimum current capable of ensuring that the zener diode is operating correctly, that is, values ​​below the minimum current mean that the component does not have the capacity to deliver its main characteristic as a voltage regulator.

The maximum current of the zener diode is the maximum current value that the zener diode can support, that is, this current value cannot be exceeded, in case this component is damaged.

Below is a table with the standard voltage values ​​for zener diodes, one table for zener diodes up to 500mW and the other for zener diodes up to 1.3W.

ner diode, besides mentioning how a Zener diode works, what are the characteristics and applications of the zener diode. Come on!

You may never have heard of the diodes, but it is very likely that you have seen diodes, since all LED panels, monitors and lamps are actually a type of diode, which is the Light Emitting Diode, popularly known as LED ( Light Emitter Diode).

Diode – What is it?

The diode is basically an electronic component that allows the passage of electric current in only one direction, according to its polarization. A simple analogy that we can make is to compare a diode to a valve that only lets water flow in one direction, that is, the diode does the same thing with the electric current, as we can see in the image below.

Diodes are like valves, allowing the passage of electric current in a single direction.

Nothing in the electronics is ideal, so to make a diode conduct electricity you need to supply it with a voltage of at least 0.7V between anode and cathode, considering silicon diodes, that is, less than that the diode is not capable of a drive.

The diodes can perform specific functions such as capacity varies depending on the voltage, voltage regulator, light emission, such as varicap, Zener and LED respectively. In addition to these diodes that have been mentioned, we can mention other types of diodes with specific characteristics such as, for example, Schottky diode, photodiode, Gunn diodes and tunnel diode. In the image below we can see the diode symbologies that were mentioned.

Description and symbologies for different types of diodes.

Zener Diode

The Zener diode, also known as voltage regulator diode, is named after the American physicist Clarence Melvin Zener, he was the first to describe that the breaking mechanism of electrical insulators is a type of diode, which unlike most applications for the diodes, which operate in the conduction region, the Zener always operates reverse polarized.

Zener diode – Operation

Therefore, in order for us to understand how the Zener diode works, we need to understand its characteristic curve, as we can see in the image below:

The characteristic curve of the Zener diode.

The part that interests us to understand the operation of the Zener diode is located in the fourth quadrant of the graph above, where we find the cut and avalanche region of a diode, which is where the diode is reversedly polarized.

As we can see, while the reverse voltage is lower than the rupture voltage, nothing different happens, characterizing a conventional diode, but when the reverse voltage approaches a value that depends on the diode being analyzed, this diode conducts and electrical current passes through it, and this current is only limited by the value of external resistances.

In this situation, even if the reverse voltage at the diode tries to be raised above the Zener voltage value, this is not possible. However, if the current increases too much, the power dissipation in the diode will increase, causing the device to reach its point of destruction, mainly due to the joule effect.

The Zener diode, operating in reverse, maintains the value of the maximum voltage between its terminals at a constant value, called the voltage of the Zener diode, however, if the Zener diode is directly polarized it will behave like a common rectifier diode.

Zener Diode – Features and Applications

Comparing the Zener diode with the common diode, we can conclude that the Zener diode is manufactured precisely to work with reverse polarization, thus, when the rupture voltage of the Zener diode is reached it becomes practically constant regardless of the current passing by the diode.

When working as a Zener diode, we must take into account some parameters such as its regulating voltage, minimum current and maximum operating current.

The regulating voltage of the Zener diode is the voltage that will remain practically constant for as long as the diode is in operation.

The minimum current is the minimum current capable of ensuring that the Zener diode is operating correctly, that is, values ​​below the minimum current mean that the component does not have the capacity to deliver its main character as a voltage regulator.

The maximum current of the Zener diode is the maximum current value that the Zener diode can support, that is, this current value cannot be exceeded, in case this component is damaged.

Below is a table with the standard voltage values ​​for Zener diodes, one table for Zener diodes up to 500mW and the other for Zener diodes up to 1.3W.