Zener Diode: Uses and Principles

by Yuvi K - December 17, 2023

What is a Zener Diode and What are its Uses?

A Zener diode is a type of diode, which allows current to flow not only from its anode to its cathode but also in the reverse direction, when the voltage across it reaches a certain level. In other words, a Zener diode is a breakdown diode that behaves like a normal diode in forward bias, and like a short circuit in reverse bias, when the voltage across it is greater than its breakdown voltage. This makes it useful for regulating voltage in electronic circuits. It is also commonly used to provide a reference voltage for various applications such as power supplies, voltage regulation, voltage multipliers and voltage dividers.

What are the Principles of a Zener Diode?

A Zener diode is designed to have a very thin junction. This thin junction allows for a lot of electron-hole pairs to be produced, making it relatively easy for current to flow in either direction, depending on the level of applied voltage. In forward bias, the Zener diode functions as a normal diode, allowing current to flow from the anode to the cathode. However, when the applied voltage exceeds the Zener diode’s breakdown voltage, which can range from 3.3 to 200 V depending on the design, the voltage across the diode will increase dramatically, allowing for a relatively large amount of reverse current to flow.

Uses of a Zener Diode

Zener diodes are used in a variety of electronic applications, including voltage regulation, voltage multipliers, voltage dividers, and power supplies.

Voltage Regulation

Zener diodes are commonly used as voltage regulators in electronic circuits. This is because Zener diodes allow a constant voltage to be maintained across the diode as long as the current through the diode remains within a specified range. This is extremely useful for regulating the output of a power supply to ensure that a varying input voltage does not cause any significant changes to the output voltage.

Voltage Multipliers

Zener diodes are also used in voltage multiplier circuits. These circuits typically consist of several stages of diodes and capacitors, which are arranged in a specific order to create a step-up voltage multiplier. The first stage contains two diodes, with one diode being a Zener diode and the other a regular diode. The Zener diode helps to create a voltage reference which is used by the capacitors in the subsequent stages to calculate the output voltage.

Voltage Dividers

Zener diodes can also be used in voltage dividers. In this configuration, Zener diodes are arranged in series with resistors. The voltage across the Zener diode remains constant, while the voltage across each resistor varies depending on the resistance. This allows for the output voltage to be divided according to specific ratios.

Power Supplies

Finally, Zener diodes are often used in power supplies in order to regulate the input and output voltages. For example, they can be used to ensure that the output voltage is stable and does not exceed a certain level. This is especially important when dealing with high voltage or high current circuits, as such circuits can be very dangerous if not properly regulated.

Conclusion

To conclude, Zener diodes are versatile devices that can be used in a number of electronic applications, such as voltage regulation, voltage multipliers, voltage dividers and power supplies. They are able to maintain a constant voltage as long as the current flowing through them remains within a certain range, making them ideal for a wide range of applications.