Q.Draw the frequency response of an amplifier with and without negative feedback.

The frequency response is a graph of voltage gain against frequency; comparing the two curves shows what negative feedback does to gain and bandwidth. …

[!TLDR]

The response is a gain-vs-frequency graph; with negative feedback the curve is lower (less gain) but wider (more bandwidth).

The frequency response of an amplifier is a plot of its voltage gain against frequency (on a log frequency scale). It has a flat mid-band region bounded by two 3 dB (0.707 of maximum) frequencies — the lower cut-off $f_1$ and the upper cut-off $f_2$ — and the bandwidth is $BW = f_2 - f_1$.

When the same amplifier is drawn with negative feedback, two changes appear:

• The peak gain falls from $A_{max}$ to $A_{f,max}$, because $A_f = A/(1+A\beta)$.
• The band widens: the lower cut-off moves down to $f_1' = f_1/(1+A\beta)$ and the upper cut-off moves up to $f_2' = f_2(1+A\beta)$, so the new bandwidth is $BW_f = BW(1+A\beta)$. …