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Semiconductor Electronics: Materials, Devices And Simple Circuits

Question
CBSEENPH12047897

A change of 8.0 mA in the emitter current brings a change of 7. 9 mA in the collector current. The value of a will be

  • 0.96

  • 0.93

  • 0.90

  • 0.99

Solution

D.

0.99

We have

         IE = IB + IC

         ΔIE = ΔIB + ΔIC

According to question,

          ΔIE = 8.0 mA

          ΔIC = 7.9 mA

    ∴    ΔI = 8.0 mA - 7.9 mA

           ΔI = 0.1 mA

  Now

          α = ICIE

Where IC is the current flowing into the collector terminal

           IB is the current flowing into the base terminal

           IE is the current flowing into the emitter terminal

         α = ICIE 

            = 7.9 mA8.0 mA

          α  = 0.99