Question

In an npn transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector, the emitter current (I_E) and base current (I_B) are given by ____________.

Options

• I_E = -1 mA, I_B = 9 mA

• I_E = 9 mA, I_B = -1 mA

• I_E = 1 mA, l_B = 11 mA

• I_E = 11 mA, I_B = 1 mA

Answer 1

In an npn transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector, the emitter current (I_E) and base current (I_B) are given by I_E = 11 mA, I_B = 1 mA.

Explanation:

`"I"_"C" = 90/100 xx "I"_"E" Rightarrow  10`

` = 0.9 xx "I"_"E"`

`therefore "I"_"E" = 10/0.9 = 11  "mA"`

`"Also"  "I"_"E" = "I"_"B" + "I"_"C" Rightarrow  "I"_"B"`

` = 11 - 10 = 1  "mA"`