Question

In an NPN transistor the collector current is 24 mA. If 80% of electrons reach collector its base current in mA is

• A. 36
• B. 26
• C. 16
• D. 6

Answer 1

Answer: (D)

6

Answer 2

Given

$\mspace{6mu} i_{c} = \frac{80}{100} \times i_{e} \Rightarrow 24 = \frac{80}{100} \times i_{e} \Rightarrow i_{e} = 30mA$

By using $i_{e} = i_{b} + i_{c}$ ⇒ i_b = 30 – 24 = 6 mA.