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The input resistance of a common emitter transistor amplifer, if the output resistance is `500 K Omega`, the current gain `alpha = 0.98` and power gain is `6.0625 xx 10^(6)`, isA. `198 Omega`B. `300 Omega`C. `100 Omega`D. `400 Omega` |
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Answer» Correct Answer - A (a) Apply the concept, power gain is product of current gain and voltage gain and find the resistance Voltage gain `= A_(V) = beta (R_(2))/(R_(1))` Also, current gain `beta = (alpha)/(1 - alpha) = (0.98)/(1 - 0.98) = 49` `A_(V) = (49) [(500 xx 10^(3))/(R_(1))]` Power gain `= 6.0625 xx 10^(6) = 49 xx [(500 xx 10^(3))/(R_(1))] xx 49` `:. R_(1) = 198 Omega` |
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