What is a Zener diode? Uses of Zener diodes

What is a Zener diode? Known as one of the semiconductor devices that allow current to flow in both forward and reverse directions. Zener diodes have a well-defined voltage and can operate in reverse bias without breakdown. So what are the structure, specifications, working principle, and some applications of this component? Let’s find out in the following article.

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What is a Zener diode

What is a Zener Diode? It is one of the silicon semiconductor devices that can allow current to flow in both forward and reverse directions. The breakdown voltage of the zener diode is well defined, and at the moment of breakdown, it begins to proceed in reverse bias mode without error.

In addition, the voltage drop across the diodes remains constant over a wide voltage range. This is one of the characteristics that make zener diodes suitable for use in voltage regulation.

The zener diode behaves like a normal diode when allowing forward current. But unlike ordinary diodes, it does not block reverse current. At this point, the zener diodes can still conduct electricity in the opposite direction.

Specifications of Zener diodes

Different diodes are defined based on specifications such as rated operating voltage, power consumption, and maximum reverse current. Some of the most commonly used parameters are:

• VZ voltage: zener voltage refers to reverse voltage from 2.4V to about 200V; it can be as high as 1kV, while the maximum for surface-mount devices (SMD) is around 47V.
• IZ max current: The maximum current rating of zener diodes is 200 µA – 200 A.
• Current IZ min: The minimum current for diode breakdown is 5 mA – 10 mA.
• Power rating: the maximum power a zener diode can dissipate multiplied by the product of the voltage across the diode and the current flowing through it. Typical values are 400 mW, 500 mW, 1W, and 5W; for surface mounting, normally 200 mW, 350 mW, 500 mW, and 1W.
• Voltage tolerance: Normally ± 5%.
• Stable working temperature: Working with a 5 volt diode voltage has the best stability.
• Zener resistor RZ is visible from the IV characteristic.

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Working principle of zener diodes

Zener diodes have the same operating principle as conventional forward diodes and have a turn-on voltage of 0.3 V to 0.7 V. It uses reverse polarity in most applications. When the reverse voltage reaches a certain value of breakdown voltage (VZ), current begins to flow through the diodes. The current rises to a maximum and is determined by the series resistance, then stabilizes and does not change over a wide range of applied voltages.

What are zener diodes used for?

With the ability to generate voltage sources that move in both forward and reverse directions, zener diodes can be applied to:

Voltage regulator

Zener diodes are very common in voltage regulators. The voltage level of the load is determined by the breakdown voltage of the semiconductor diodes. Then a series resistor limits the current passing through the diodes and reduces the excess conductivity of the diodes. At this time, the output voltage level is also more stable, ensuring stable operation of the device.

Zener diodes are used in overvoltage protection circuits

When the input voltage is higher than the zener breakdown voltage, current will flow and the voltage across the resistor will drop. During this time, the SCR transistor is activated and generates a short circuit to ground. The fuse will blow to disconnect the load to protect the device and the circuit.

Power switch with voltage stabilizer diodes

Zener diodes are also used in power switches to change and convert AC waveforms. Zener diodes are applied to limit or cut off components of one or two half cycles of an AC waveform to shape or protect electrical circuits.

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Through the above article, you must have understood what zener diodes are. If you have a need to buy products such as electronic components, soldering materials, etc. to serve in production, please come to our unit. The Tech ensures to provide the best and most quality products on the market today.