Question

For the following circuit, R2=220kΩ, R1=10kΩ, find the maximum gain and the phase shift at the cutoff frequency.

(a) Maximum gain = 22, Phase shift = 45°

(b) Maximum gain = 23, Phase shift = 135°

(c) Maximum gain = 22, Phase shift = 225°

(d) Maximum gain = 23, Phase shift = 45°

The question was asked in a national level competition.

My doubt is from Frequency Filters in section Op-amps and its Applications of Analog Circuits

Answer 1

Right choice is (d) Maximum gain = 23, Phase shift = 45°

Explanation: Above is a high pass filter, with maximum gain = 1+R2/R1 = 23

Phase shift = tan^-1(1) = 45°.