In a CE transistor, a change of $8.0 \mathrm{~mA}$ in the emitter current produces a change of $7.8…

In a CE transistor, a change of $8.0 \mathrm{~mA}$ in the emitter current produces a change of $7.8 \mathrm{~mA}$ in the collector current. What change in the base current is necessary to produce the same change in the collector current?
  1. $200 \mu \mathrm{A}$
  2. $50 \mu \mathrm{A}$
  3. $100 \mu \mathrm{A}$
  4. $150 \mu \mathrm{A}$

Solution

$\begin{aligned} & \Delta \mathrm{I}_{\mathrm{E}}=\Delta \mathrm{I}_{\mathrm{C}}+\Delta \mathrm{I}_{\mathrm{B}} \\ & \Delta \mathrm{I}_{\mathrm{E}}=8 \mathrm{~mA}, \Delta \mathrm{I}_{\mathrm{C}}=7.8 \mathrm{~mA} \\ & \therefore \Delta \mathrm{I}_{\mathrm{B}}=\Delta \mathrm{I}_{\mathrm{E}}-\Delta \mathrm{I}_{\mathrm{C}}=8-7.8=0.2 \mathrm{~mA}=200 \mu \mathrm{A}\end{aligned}$

Asked in: MHT CET 2021 (24 Sep Shift 1)

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