Zener Diode(497)

A Zener diode is a type of semiconductor diode that is designed to allow current to flow in the reverse direction when a specific voltage, known as the Zener breakdown voltage or Zener voltage (Vz), is reached. Unlike regular diodes, which block reverse current, Zener diodes are intentionally operated in the reverse breakdown region to provide voltage regulation in electronic circuits. This unique property makes Zener diodes useful for applications such as voltage regulation, overvoltage protection, and reference voltage generation.

Key Characteristics of a Zener Diode:

1. Reverse Breakdown Operation:

• The defining feature of a Zener diode is its ability to operate in reverse breakdown without damage. When the reverse voltage across the Zener diode reaches the Zener voltage (Vz), it starts to conduct and maintains a nearly constant voltage across its terminals, regardless of the current passing through it (within specified limits).

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2. Zener Voltage (Vz):

• The Zener voltage is the voltage at which the diode enters reverse breakdown and begins to conduct. Zener diodes are available with different Zener voltages, typically ranging from 2.4V to 200V, depending on the application requirements.

• The Zener voltage is a key parameter used to regulate the voltage in circuits.

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3. Forward-Biased Operation:

• When a Zener diode is forward-biased, it behaves like a normal diode, with a typical forward voltage drop of about 0.7V for silicon Zener diodes.

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4. Low Zener Impedance:

• Zener impedance (Zz) refers to the dynamic resistance of the diode in the reverse breakdown region. Low Zener impedance means that the voltage across the diode remains stable even with changes in current, making it effective for voltage regulation.

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5. Power Dissipation:

• The power rating of a Zener diode is a measure of the maximum power it can dissipate without being damaged. It is calculated as the product of the Zener voltage and the current passing through it.