An n-p-n transistor in a common-emitter mode is used as a simple voltage-amplifier with a collector current of 4 mA. The terminals of a 8 V battery is connected to the collector through a load-resistance `R_L` and to the base through a resistance `R_B`. The collector-emitter voltage `V_(CE)=4V`, the base-emitter voltage `V_(BE) = 0.6 V` and the current amplification factor `beta_(dc) = 100`. Then

Explanation

Given, `i_(c) = 4 mA` applying Kirchhoff's second law in loop 1.
`V_(CE)=8-I_(C) R_(L)rArr R_(L)=(8-V_(CE))/(i_(c))=(8-4)/(4 xx 10^(-3))=1 xx 10^(3) Omega =1 k Omega`
`I_(B) = (I_(C))/(beta) = (4 mA)/(100) = 4 xx 10^(-5)A`
`because V_(BE) =8-I_(B)R_(B)rArr R_(B)=(8-V_(BE))/(I_(B))=(8-06)/(4 xx 10^(-5))=185 k Omega`
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