An NPN transistor is used in common emitter configuration as an amplifier with `1 k Omega` load resistance. Signal voltage of 10 mV is applied across the base-emitter. This produces a 3 mA change in the collector current and `15 mu A` change in the base current of the amplifier. The input resistance and voltage gain are:

Options

A. 0.67 `komega` 300
B. 0.67 `komega` 20
C. 0.33 `komega` 1.5
D. 0.33 `komega` 300

Explanation

Input current (base current ) `=15 xx 10^(-6)`
Output resistance `=1000 Sigma`
`V_("input") = i_("input") xx R_("input")`
`10 xx 10^(-3) R_("input") xx 15 xx 10^(6)`
Voltage gain `= (V_("out"))/( V_("input") )= (3xx 10^(-3) xx 1000)/( 10 xx 10^(-3)) =300`
we can see that option (a) is correct