Question

The injected excess electron concentration profile in the base region of an npn BJT, biased in the active region, is linear, as shown in the figure. If the area of the emitter-base junction is $0.001c{m}^2,{\mu }_n=800c{m}^2/(V-s)$ in the base region and depletion layer widths are negligible, then the collector current $I_c\left(inmA\right)$ at room temperature is (Given : thermal voltage $V_T=26mV$ at room temperature,electronic charge $q=1.6\times {10}^{-19}C)$

• A. 6.656

Answer 1

The correct option is A 6.656
$I_c=Aq{D}_n\frac{dn}{dx}where{D}_n={\mu }_n{V}_T$ $=0.001(1.6\times {10}^{-19})800\times 26\times {10}^{-3}\left[\frac{{10}^{14}}{0.5\times {10}^{-4}}\right]$
$=66.56\times {10}^{-4}a=6.656mA$