# Difference between resonance and cutoff and corner frequency of a filter

#### mishra87

Joined Jan 17, 2016
984
Hi all,

Could anybody explain me a bit about resonance and cutoff frquency.
Is there any difference in formulas.
How to calculate these frequency.

Thanks !!!

#### WBahn

Joined Mar 31, 2012
28,161
They are two different concepts. What has your own efforts to find the answer yielded so far?

#### mishra87

Joined Jan 17, 2016
984
They are two different concepts. What has your own efforts to find the answer yielded so far?
I found the same equation to calculate resonant as well as corner frequency !!

1. Resonant frequency -
XL=XC

2. Corner frequency-
-3db point where power to be reduced by half(db/decade)

#### WBahn

Joined Mar 31, 2012
28,161
I found the same equation to calculate resonant as well as corner frequency !!
View attachment 152768

1. Resonant frequency -
XL=XC

2. Corner frequency-
-3db point where power to be reduced by half(db/decade)
Where did you find this same equation for both?

What kind of circuit are we talking about?

Have you tried using the definitions given above to determine those frequencies for that circuit?

#### Papabravo

Joined Feb 24, 2006
19,826
@mishra87 Do you think it is possible that the same equation can describe the behavior of two or more different circuits?
How many different circuits can you construct with a single lumped C and a single lumped L? I can think of at least four.
What happens in those circuits when we ask: "for what frequency is the capacitative reactance equal to the inductive reactance".

#### mishra87

Joined Jan 17, 2016
984
I might be misunderstood that's the reason I posted my query to let someone clarify it.

Thanks @Papabravo @WBahn

#### Papabravo

Joined Feb 24, 2006
19,826
I might be misunderstood that's the reason I posted my query to let someone clarify it.

Thanks @Papabravo @WBahn
And by applying the Socratic method we ask you a series of questions that should lead you to the answer. You can choose not to play if you wish.