Question

In Bipolar Junction Transistor (BJT), Justify the relation IE = IB + IC. (From Chapter - Semiconductor Devices)

Answer 1

Given: Bipolar Junction Transistor (BJT)

To find: Justify the relation I(E) = I(B) + I(C)

Solution:

• The three terminals are known as the Emitter ( E ), the Base ( B ) and the Collector ( C ) respectively.

• Now we know that α is I(C) / I(E) which is current gain.

• β is I(C) / I(B) which is transistors current gain.

                   α =  I(C) / I(E)    ..............(i)

                   β =  I(C) / I(B)    ..............(ii)

• From (i) and (ii), we get:

                   I(C) = α.I(E) = β.I(B)

• As α = β / β + 1 and β = α / 1 - α, so:

                   I(E) = I(B) + I(C)

Answer:

            So the relation is justified.