Consider the following statement S1 and S2.S1: The 8 of a bipolar tran...
Β = ICIB = α1-αwhen base width increases , recombination in base region increases and α decreases & hence β decreases.If doping in base region increases , then recombination in base increases and α decreases thereby decreasing β.
Consider the following statement S1 and S2.S1: The 8 of a bipolar tran...
Introduction:
In this question, we are given two statements, S1 and S2, related to the behavior of a bipolar transistor. We need to determine which statement is true and which is false.
Explanation:
S1: The 8 of a bipolar transistor reduces if the base width is increased.
The Early effect (or Early voltage) is a phenomenon observed in bipolar transistors. It refers to the variation in the output current with changes in the collector voltage, keeping the base-emitter voltage constant. The Early voltage, denoted by Va, is typically in the range of 50-150V for general-purpose transistors.
The Early voltage, Va, is inversely proportional to the base width (Wb) of the bipolar transistor. Mathematically, we can express this relationship as:
Va ∝ 1/Wb
Therefore, if the base width is increased, the Early voltage will decrease. Hence, Statement S1 is true.
S2: The B of bipolar transistor increases if the doping concentration in the base is increased.
The B of a bipolar transistor refers to the current gain or amplification factor. It is denoted by hfe or β. The value of B is determined by the doping concentration in the base region of the transistor.
In a common-emitter configuration, the current gain (hfe) is given by the ratio of the collector current (IC) to the base current (IB). Mathematically, we can express this relationship as:
hfe = IC/IB
The current gain (hfe) is directly proportional to the doping concentration in the base region. Therefore, if the doping concentration in the base is increased, the current gain of the transistor will also increase. Hence, Statement S2 is true.
Conclusion:
Based on the explanations above, we can conclude that Statement S1 is true and Statement S2 is also true. Therefore, the correct answer is option D) S1 is true and S2 is false.
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