Physics Practicals Class 12

# Zener Diode

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• Zener diode experiment is one of the important class 12 physics practicals that you can learn in our virtual lab.
• In this simulation, you will get the knowledge of the basics of Zener diode, its working system, plotting characteristics of a Zener diode and calculating its breakdown voltage.
• You will learn about Avalanche and Zener breakdown in PN junction.
• You will study about the application of Zener diode as a voltage regulator.
• All the experiment steps and procedures like determining the least counts, arranging the experimental setup, adjusting the rheostat, noting down the readings, plotting the graphs, etc., and many more are highly interactive and have been simulated in a very similar manner as you do in a physics lab.

• This interaction provides a very immersive environment and gives you a real-lab-like experience while conducting or performing experiments.
• This will help learners to better prepare for various competitive exams such as IIT-JEE (JEE Main & Advanced), NEET, and Olympiads.

### Simulation Details

Duration – 30 Minutes
Easily Accessible
Language – English
Platforms – Android & Windows

Description

A Zener diode is a silicon semiconductor device that permits current to flow in either a forward or reverse direction. The Zener diode has a reverse-breakdown voltage, at which it starts conducting current, and continues operating continuously in the reverse-bias mode without getting damaged. The following two mechanisms can cause a breakdown in a junction diode:

### (i) Avalanche breakdown

With increasing reverse bias voltage, the electric field across the junction of p-n diode increases. At a certain reverse bias, the electric field imparts a sufficiently high energy to a thermally generated carrier crossing the junction. This carrier disrupts a covalent bond and produces an electron-hole pair. This process is cumulative and produces an avalanche of carriers in a very short time. This mechanism is known as avalanche multiplication, causes large reverse current and the diode is said to work in the region of avalanche breakdown.

### (ii) Zener breakdown

In a Zener diode, both the p and n-sides are heavily doped. Due to the high dopant densities, the depletion layer junction width is small. This high junction field may strip an electron from the valence band, which can tunnel to the n-side through the thin depletion layer. Such a mechanism of emission of electrons after applying a certain electric field is termed as internal field emission which gives rise to a high reverse current or breakdown voltage. This breakdown is termed as Zener breakdown.

To protect a diode from damage, we connect a protective resistance to a Zener diode which limits maximum current. Also, Zener diode is used as a voltage regulator.

### Requirements for this Science Experiment

Zener Diode Voltmeter Milliammeter Plug Key Rheostat Battery Resistance

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