For CE transistor amplifier, the audio signal voltage across the collector resistance of `2 kOmega` is 4V. If the current amplification factor of the transistor is 100 and the base resistance is `1kOmega`, then the input signal voltage is

Options

A. 10 mV
B. 20 mV
C. 30 mV
D. 15 mV

Answer

B

Explanation

Here, `R_(C )=2kOmega=2kOmega=2000Omega, V_(0)=4V`
`beta=100, R_(B)=1kOmega=1000Omega, V_(i)=?`
Voltage gain, `A_(v)=beta(R_(C ))/(R_(B))=100xx(2000)/(1000)=200`
Also, `A_(v)=(V_(0))/(V_(i))` or `V_(i)=(V_(0))/(V_(i))` or `V_(i)=(V_(0))/(A_(v))=(4)/(200)=(2)/(100)V=20mV`