Zener Diode Interview Questions

February 16, 2024 Post a Comment

Zener diode interview questions

A Zener diode operates just like a normal diode when it is forward-biased. However, a small leakage current flows through the diode when connected in reverse biased mode. As the reverse voltage increases to the predetermined breakdown voltage (Vz), current starts flowing through the diode.

What is Zener diode short answer?

A Zener diode is a special type of diode designed to reliably allow current to flow "backwards" when a certain set reverse voltage, known as the Zener voltage, is reached.

What is Zener diode and its uses?

Zener diode acts as a voltage regulator When the load voltage equals the breakdown voltage, the resistors which are connected in series limit the current through the diode when there is an excess amount of voltage while the diode is conducting.

How does Zener limit voltage?

Zener Diode Regulator Resistor, RS is connected in series with the zener diode to limit the current flow through the diode with the voltage source, VS being connected across the combination. The stabilised output voltage Vout is taken from across the zener diode.

What is Zener voltage called?

Voltage regulator diodes actively use this characteristic. Since this breakdown voltage is also called Zener voltage, voltage regulator diodes are also called Zener diodes. This voltage may be used as a constant voltage power supply or a reference voltage for electronic circuits.

What is Zener diode symbol?

In zener diode, electric current flows from both anode to cathode and cathode to anode. The symbol of zener diode is similar to the normal p-n junction diode, but with bend edges on the vertical bar.

Is Zener diode used in AC or DC?

Hence, the Zener diode acts as a voltage regulator. Therefore, the Zener diode is used as an A.C. voltage regulator.

Why Zener diode is called so?

A Zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the rated breakdown voltage or "Zener voltage". The device was named for Clarence Zener, who discovered this electrical property.

What causes a Zener diode to fail?

Excessive temperature will destroy a zener diode, and because it both drops voltage and conducts current, it produces its own heat in accordance with Joule's Law (P=IE). Therefore, one must be careful to design the regulator circuit in such a way that the diode's power dissipation rating is not exceeded.

What is minimum Zener current?

It's knee current, breakdown current, or minimum current is 0.25 mA. The maximum current is calculated by dividing the power rating by the Zener voltage: I=P/V = 3W/12V = 0.25A.

Where is Zener diode used?

Zener diodes are used for voltage regulation, as reference elements, surge suppressors, and in switching applications and clipper circuits. The load voltage equals breakdown voltage VZ of the diode.

Does a Zener have resistance?

A zener has an internal resistance, think of is as a series resistor inside the diode. Its a dynamic resistance – it changes with current, temperature etc. Power – Remember your zener will heat up by the amount of power it is dissipating, just like say a linear voltage regulator!

Is Zener active or passive?

A normal PN junction diode is passive whereas tunnel diode or zener diode is active component due to their negative resistance property.

Is a TVS a Zener?

Thus, a TVS diode absorbs surge voltage to protect other semiconductor devices, whereas a Zener diode provides constant voltage to other semiconductor devices.

What is another name of Zener diode?

Zener diode is also known as breakdown diode as it works in reverse bias breakdown for voltage regulation. It is PN junction (silicon PN junction) diode and has a low specified reverse voltage which takes advantage of any reverse voltage applied to it.

Why Zener diode is highly doped?

Why is the p-n junction of the zener diode heavily doped? The p-n junction of the Zener diode is heavily doped to get a narrow depletion region. The narrow depletion region allows the ions to easily gain energy from the external source. In the reverse bias, the junction potential of the Zener diode is increased.

What is a Zener current?

The current, IZM, of a Zener diode is the maximum current that can flow through a Zener diode at its rated voltage, VZ. Typically there is also a minimum current required for the operation of the diode. As a rough rule of thumb, this can be around 5 to 10 mA for a typical leaded 400 mW device.

What is breakdown voltage?

Breakdown voltage is the threshold voltage at which the initiation of breakdown occurs. However, before current can flow, the open gap voltage increases until it has created an ionization path through the dielectric. Once the current starts to flow, voltage drops and stabilizes at the working gap level.

Can Zener be used as rectifier?

Answer: We donot use a zener diode in a rectifier circuit because in a rectifier circuit a high maximum peak inverse voltage is required. Zener diode has low inverse peak voltage unlike other normal diodes. This is the reason zener diode is not used in rectification purpose.

What is Zener diode made of?

The true Zener diodes, which have the same properties as avalanche diodes and are used in the same applications, rely on the Zener effect. The diode is made from heavily doped silicon, so that the depletion layer is very thin.