..........biasing of p-n junction offers high resistance to current flow across the junction. The bi

Q: Why does reverse bias offer high resistance?

In reverse bias, the applied voltage pulls the majority charge carriers away from the junction. This widens the depletion region, which lacks free charge carriers and acts like an insulator, offering high resistance.

Q: Does absolutely zero current flow in reverse bias?

Not exactly zero. A very small current, called the reverse saturation current, still flows. This is due to the minority charge carriers (electrons in $p$-type and holes in $n$-type) being pushed across the junction.

Q: What happens if we increase the reverse bias voltage too much?

If the reverse voltage exceeds a certain critical value, the junction undergoes breakdown (Zener or Avalanche breakdown). This leads to a sudden, massive flow of current which can permanently damage the diode if not controlled.

Q: Why is the $p$-side connected to the negative terminal in reverse bias?

The $p$-side is rich in positively charged holes. Connecting it to the negative terminal attracts these holes away from the junction, which is necessary to widen the depletion region and stop the current.

Q: What is the practical use of a reverse-biased diode if it doesn't conduct?

Reverse-biased diodes are incredibly useful! They are used in voltage regulation (Zener diodes), tuning circuits (varactor diodes), and light detection (photodiodes), where their high resistance and breakdown properties are exploited.

Question

..........biasing of $p$-$n$ junction offers high resistance to current flow across the junction. The biasing is obtained by connecting the $p$-side to the ........ terminal of the battery.

Sigma Percentile · Accepted Answer

### The Magic of the P-N Junction

Imagine a bustling city where people are constantly moving. Now, imagine putting up a massive wall right in the middle of the city. Suddenly, the movement stops. This is exactly what happens inside a $p$-$n$ junction when we apply a **reverse bias**.

A $p$-$n$ junction is the heart of modern electronics, formed by joining a $p$-type semiconductor (rich in positively charged holes) and an $n$-type semiconductor (rich in negatively charged electrons). When they meet, a small border zone is created called the **depletion region**, where the charges cancel each other out, leaving behind fixed ions.

### Setting Up the Reverse Bias

To control the flow of current, we connect this junction to a battery. If we want to stop the current, we use a setup called **reverse biasing**. In this configuration, we connect the $p$-side of the junction to the **negative terminal** of the battery, and the $n$-side to the **positive terminal**.

Why do we do this? It's all about manipulating the charge carriers. The positive holes in the $p$-side are strongly attracted to the negative terminal of the battery. Similarly, the negative electrons in the $n$-side are pulled towards the positive terminal.

### The Wall Gets Thicker

As the majority charge carriers are pulled away from the central junction towards the edges, the depletion region in the middle starts to widen. Think of it as the wall in our city getting thicker and taller.

This widened depletion region is devoid of any free charge carriers. Without free carriers, electricity cannot flow. Therefore, this thick depletion region acts as an insulator, offering **very high resistance** to the flow of current.

### The Final Verdict

Because of this massive resistance, practically zero current flows across the junction (except for a tiny leakage current due to minority carriers).

So, returning to our original question: It is the **reverse** biasing of a $p$-$n$ junction that offers high resistance to current flow. And how do we achieve this? By connecting the $p$-side to the **negative** terminal of the battery. Understanding this simple yet profound mechanism is the key to unlocking the secrets of diodes, transistors, and the entire digital world!

Animated Solution for Physics - Semiconductors: ..........biasing of $p$ - $n$ junction offers high resistance to current flow across the junction. The biasing is obtained by connecting the $p$ -side to the ........ terminal of the battery.

Visualized Solution

$p$ - $n$ \text{ Junction Biasing}

\text{Reverse Bias Setup}

\text{Effect on Majority Carriers}

\text{Widening of Depletion Region}

\text{High Resistance}

\text{Conclusion}

The Sigma Insight: P-N Junction Diode

The Magic of the P-N Junction

Setting Up the Reverse Bias

The Wall Gets Thicker

The Final Verdict

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