Hi,

can someone help with this question . The cutoff frequency of the low pass filter below is not 4.8 kHz but 1.8kHz . and i dont understand why . Shouldnt the cutoff frequency be the cutoff frequency of the input RC: 1/2*Pi*R*C ?

 

hi Sk,
This a LTspice sim
E


Update:

Post your actual calculations.

 

That is not an active filter, it is a passive RC filter with a non-inverting op amp buffer on the output.
Active filters have feedback from the output to the input network.

The cutoff frequency of the low pass filter below is not 4.8 kHz but 1.8kHz

Why do you say that?

 

Hey , guys Thanks a lot for your help. Its an online practice test that i found on the internet. And the "Correct" answer is also given for each question. For this question , the supposed correct answer was 1.8 kHz. I had doubts that there would be mistakes but , you guys confirmed it .

Thank you !