A Zener diode is a semiconductor having a p-n junction that functions as a transistor when utilised in reverse biassing. It performs similarly to a normal signal diode when run in forward bias; however, when operated in reverse voltage, the voltage remains constant throughout a wide range of currents. It can be employed in a variety of applications because of this feature, such as voltage regulators in direct current circuits. The Zener diode acts as a voltage regulator, ensuring that a consistent voltage level is maintained. If you utilise a 10 V Zener voltage, the voltage will remain constant at 10 V, and the Zener Diode will help you keep the voltage constant.
It is a device that aids in the regulation of the circuit’s voltage level. It helps by scaling down the input voltage to the required level and keeping it constant throughout the supply. This assists in maintaining a steady load. The voltage regulator is in charge of two major tasks:
- To assist with output voltage control.
- To aid in the stabilisation of the output voltage and its steady maintenance at the correct value, even when there are variations.
Voltage regulators can be found in a variety of electrical and electronic devices, such as computers, alternators, and other similar devices.
Use of Zener Diode as a Voltage Regulator
A series resistor is connected to the circuit when employing a Zener Diode to limit the amount of current that can flow through it. It is connected to the positive terminal of the direct current (the +ve terminal). If we apply reverse bias above the breakdown voltage to any low power rating diode, the diode will be severely damaged and will be unable to work even under normal voltage settings.
The zener diode current should always be at its lowest possible value if we apply the lowest possible input voltage while concurrently supplying the highest possible load current.
Best way to depict the Zener Diode Circuit
We should always pay attention to the positive and negative terminals when inserting a Zener diode into a circuit because we already know that they perform best under Reverse Biassed circumstances. The p-type material should be linked to the diode’s negative terminal, while the n-type material should be attached to the diode’s positive terminal. The depletion zone in a Zener diode is exceedingly tiny when compared to the depletion region in a regular diode because it is severely doped.
What is the Function of the Zener Diode?
This is mostly owing to the diode’s addition of impurities, which helps to increase its conductivity, making it more suitable for our applications. Zener diodes have a very small depletion region, which is owing to the addition of impurities to the diode, which improves its conductivity and makes it more suitable for our purposes. Any voltage given to the system through this diode increases the intensity of the field across the depletion area, no matter how tiny the voltage applied.
The valence band of a p-type semiconductor material is a region where electrons are attracted to one another. As a result, the diode does not have any current flowing through it. The valence band electron is the electron that belongs to this band. When external energy is given to this section of the periodic table, electrons begin their journey from one valence band to the next.
The diode conducts itself in reverse-bias mode when the Zener voltage equals the supply voltage, which is an unexpected result. It’s vital to remember that the Zener voltage is the voltage at which the depletion region thins out and practically vanishes.
The electric field intensifies when the depletion area thins down due to the increasing current flow when a reverse bias is applied across the diode. As a result of this transition, electrons shift from the valence band of the p-type semiconductor material to the conduction band of the n-type semiconductor material. The barrier between the two substances is broken down by this movement. The diode conducts current in the opposite direction of the bias current field at this voltage and current field level.
Characteristics of the Zener Diode
When in forward bias mode, the Zener diode functions precisely like any other diode on the market. The reverse voltage, on the other hand, rises when the reverse bias is applied. As a result, the Zener diode suffers a complete collapse.
As a result of the breakdown, which occurs at a voltage known as the breakdown voltage, the current is forced to flow in the opposite direction. The graphs show that the Zener diode has a large amount of resistance and that it does not break down in a linear or vertical manner.
As a result, the voltage of a Zener diode can be calculated using the following equation: V = VZ + IZRZ.
Zener Diode Applications
Zener diodes are the most prevalent type of diode used in industrial and commercial settings. When it comes to voltage regulation, a voltage stabiliser is employed. In this situation, voltage variations are transformed to constant voltages, which are subsequently sent to the power load. As a result, the Zener diode is frequently wired in parallel with the load. It is a great voltage regulator or stabiliser due to its ability to maintain a consistent voltage.
Due to the huge volume of electricity utilised in commercial and industrial buildings, massive power-metre systems are prone to metre overloads. These multimeters, on the other hand, are wired in series with the Zener diode, preventing the system from becoming overloaded by accident. Even if there is an overload, the majority of the current is deflected through the diode, preventing the metre from being damaged.
A sine wave can be readily turned into a square wave by connecting two Zener diodes back to back and in opposing directions in series with the circuit’s resistance.
The Zener diode also has certain criteria, such as the Zener voltage, the minimum and maximum currents required for breakdown, the amount of power that the diode can waste, the diode’s temperature stability, and the Zener resistance.
Current flows from the anode to the cathode in Zener diodes in a usual manner. This silicon semiconductor has been developed to perform adequately in the presence of reverse bias. The current can be reversed and the circuit shut down if the voltage exceeds a certain value, known as the breakdown voltage. In addition, by applying reverse voltage to the Zener diode, the voltage is guaranteed to remain constant over a wide variety of current flows.
A Zener diode is a silicon semiconductor device that allows current to flow in either a forward or a reverse direction depending on the current flow direction. The diode is composed of a special, strongly doped p-n junction that is designed to conduct in the opposite way when a specific voltage is attained. Despite having a clearly defined reverse-breakdown voltage, at which point it begins to conduct current, the Zener diode is capable of continuing to operate continuously in the reverse-bias mode without being destroyed. The voltage drop across the diode is also consistent over a large range of voltages, which makes Zener diodes appropriate for use in voltage control applications, as previously stated.