Question

The base current for a transistor is measured as $100\mu A.If\alpha =0.98and{I}_{CBO}=5\mu A$, then the value of collector current is

• A. 5.45 mA
• B. 5.15 mA
• C. 5.35 mA
• D. 4.95 mA

Answer 1

The correct option is B 5.15 mA

$I_{CBO}=5\mu A$
$I_B=(1-\alpha )I_E=I_{CBO}$
$I_E=\frac{I_B+I_{CBO}}{(1-\alpha )}=\frac{100+5}{(1-0.98)}=\frac{105}{0.02}=5.25mA$
$I_C=I_E-I_5$
$=5.25-0.1=5.15mA$