What is zener diode how a zener diode could be used as voltage regulator 2?
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Answer:
A diode is the first semiconductor diode. A diode can be defined as the fundamental electronic component that allows the flow of electricity in one direction only. There are many types of diodes. One among them is Zener diode. It allows current to flow not only from anode to cathode, but also, in the reverse direction on reaching Zener voltage. Due to this functionality, Zener diodes are the most commonly used semiconductor diodes, etc.
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A conventional reverse biased diode, when subjected to its breakdown voltage allows a significant amount of current. But when this reverse breakdown voltage is exceeded, the diode experiences an avalanche breakdown.
Avalanche breakdown is a form of electric current conduction that allows very large current to pass through good insulators. This may permanently damage a conventional diode.
A Zener diode exhibits the same properties except it is designed to have a reduced breakdown voltage. In contrast to the conventional diode, it exhibits a controlled breakdown.
When we increase the voltage through Zener in reverse bias mode, first current increases uniformly with it but after it reaches the breakdown state, the current increases massively for a very small or negligible change in voltage. The change is sharper in Zener than the normal diode.
Related Article:
Difference Between Zener Breakdown and Avalanche Breakdown
Causes of Breakdown
The breakdown is caused by two effects, the Avalanche effect and the Zener effect. The Zener effect is dominant in voltages up to 5.6 volts and the avalanche effect takes over above that.
They are both similar effects, the difference being that Zener effect is a quantum phenomenon and the avalanche effect is the movement of electrons in the valence band like in any electric current.
Avalanche effect also allows a larger current through the diode than the Zener effect.
Application of Zener Diode
Following are the applications of Zener diode:
Zener diode as voltage regulator:
Zener diode is used as Shunt voltage regulator for regulating voltage across small loads. The breakdown voltage of Zener diodes will be constant for a wide range of current. Zener diode is connected parallel to the load to make it reverse bias and once the Zener diode exceeds knee voltage, the voltage across the load will become constant.
Related Article:
Zener Diode as a Voltage Regulator
Zener diode in over-voltage protection:
When the input voltage is higher than the Zener breakage voltage, the voltage across the resistor drops resulting in short circuit. This can be avoided by using Zener diode.
Zener diode in clipping circuits:
Zener diode is used for modifying AC waveform clipping circuits by limiting the parts of either one or both the half cycles of an AC waveform.
