In transistors, the base region is thin and lightly doped elsea)collector current will be much larger than the emitter currentb)the electrons or holes will not be able to reach the collectorc)the transistor will be very thickd)the base current will decreaseCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

In a transistor, base bring interaction between emitter and collector. In a transistor, the base region is made very thin and lightly doped as compared to that of an emitter so that there may be less recombination of electrons and holes in this region. Due to which the base current is quite weak and the collector current is nearly equal to the emitter current.
If the base region of a transistor is doped equally to that of the emitter region, then a large electron hole recombination will take place in base, due to it, the base current would increase but collector current would decrease. Then the very purpose of a transistor would be defeated.

Answer

Base is lightly doped otherwise the most of the charge carries from the emitter recombine in base region
and
none of the emitted carrier reaches at collector

Answer

Explanation:
The base region in a transistor is thin and lightly doped for several reasons. One of the main reasons is to ensure that the electrons or holes can easily reach the collector region.

1. Collector Current:
If the base region is thick and heavily doped, it would result in a much larger collector current compared to the emitter current. This is because a thick base region would provide more carriers for recombination, allowing a larger number of electrons or holes to flow from the collector to the base. This would cause an imbalance in the transistor operation and affect its performance.

2. Carrier Movement:
When a transistor is in operation, the base-emitter junction is forward-biased, which allows the flow of electrons from the emitter to the base. These electrons must traverse the thin base region to reach the collector. If the base region is not thin, the electrons or holes will not be able to easily cross the base region and reach the collector. This would hinder the transistor's ability to amplify the input signal.

3. Transistor Thickness:
If the transistor is very thick, it would result in a larger distance for the electrons or holes to travel from the emitter to the collector. This would increase the transit time and delay the response of the transistor. A thin base region ensures that the carriers can quickly move from the emitter to the collector, enabling faster operation.

4. Base Current:
In a transistor, the base current controls the flow of electrons or holes from the emitter to the collector. If the base region is too thick, it would decrease the base current. This would result in reduced amplification and a weaker output signal. Therefore, a thin base region is necessary to maintain the required base current and ensure proper transistor operation.

In conclusion, having a thin and lightly doped base region in a transistor is essential to allow the easy movement of electrons or holes from the emitter to the collector. This ensures proper transistor operation, balanced current flow, and efficient amplification of the input signal.

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