Semiconductor Electronics Materials Devices And Simple Circuits

Given, and
We know that in a transistor amplifier

Now,

When a small amount of pentavalent impurity is added to intrinsic germanium, it is known as n-type semiconductor. Typical examples of pentavalent impurities are arsenic, antimony, phosphorus.

Given that, the density of electron hole pair in an intrinsic
semiconductor
density of holes
We know that

Step 1: Understanding p-n junction behavior.
When a p-n junction diode is forward biased, the positive terminal of the power source is connected to the p-type material, and the negative terminal is connected to the n-type material. This reduces the potential barrier.
Step 2: Explanation of current flow.
In forward bias, the reduced potential barrier allows current to flow easily from the p-side to the n-side. The decrease in the barrier facilitates the flow of charge carriers (electrons and holes).
Step 3: Conclusion.
When the diode is forward biased, the potential barrier decreases, allowing current to flow. Hence, the correct answer is (A).

Step 1: Understanding the Concept:
Doping semiconductors involves adding impurities. Trivalent impurities (Group 13) create P-type semiconductors, while Pentavalent impurities (Group 15) create N-type.
Step 2: Detailed Explanation:
* Trivalent (3 valence electrons): Boron (B), Aluminium (Al), Gallium (Ga), Indium (In). * Pentavalent (5 valence electrons): Phosphorus (P), Arsenic (As), Antimony (Sb), Bismuth (Bi). Antimony belongs to Group 15 and is therefore pentavalent.
Step 3: Final Answer:
The correct option is (b).

Step 1: Understanding the Concept:
A full-wave rectifier converts both halves of the AC cycle into pulsating DC. This effectively doubles the frequency of the "pulses" compared to the original wave.
Step 2: Detailed Explanation:
For a Full-Wave Rectifier: .
Given .
$ $
Step 3: Final Answer:
The correct option is (a).

Step 1: Understanding the Concept:
Forward bias occurs when the P-side is connected to the positive terminal and the N-side to the negative terminal of a battery.
Step 2: Detailed Explanation:
In forward bias, the applied voltage opposes the built-in potential (barrier potential) of the depletion layer. This reduces the width of the depletion region and lowers the potential barrier, allowing majority carriers to diffuse across the junction easily, resulting in a large current.
Step 3: Final Answer:
The correct option is (b).