JEE Main2018PhysicsSemiconductorsActual
In a common emitter configuration with suitable bias, it is given that R L is the load resistance and R B E is small-signal dynamic resistance (input side). Then, voltage gain, current gain and power gain are given, respectively, by: β is current gain, I B , I C and I E are respectively base, collector, and emitter currents.
Options
- Aβ R L R B E , Δ I C Δ I B , β 2 R L R B E
- Bβ R L R B E , Δ I E Δ I B , β 2 R L R B E
- C  β 2 R L R B E , Δ I C Δ I B , β R L R B E
- D  β 2 R L R B E , Δ I C Δ I E , β 2 R L R B E
Correct answer
A. β R L R B E , Δ I C Δ I B , β 2 R L R B E
Step-by-step solution
For a common emitter configuration, current gain, β = Δ I C Δ I B . Voltage gain is the ratio of output voltage to the input voltage. It is given as, A V = Δ V C E   R B E Δ I B = β R L R B E (Since from Ohm's law, R L = ∆ V C E ∆ I B ). Power gain A P = β A V = β 2 R L R B E .