Answer / ashish

None of you has explained, what happens if I take 4 dB or 5
dB point.
Every one knows that at 3 dB point, power becomes half....so
what?

Answer / john lam

A filter's cutoff frequency is generally, but not
necessarily based on the type of filters, defined at -3dB.
At this point, the voltage of the input has attenuated to
70.71%, or in power form 50%. After this point, the voltage
of the input will drop dramatically rendering it useless.
Therefore the -3dB point is picked as the cutoff frequency
point because of this nature. It's not chosen randomly.

*** Sorry, last one has typo errors by mixing up the two
percentages. This one is correct.

Answer / sigma 6

The question is only asking, why not any integer between 0
and 3 Db.


Answer No.5 grips the teory of the question, and answer no.
6 Explains the applicability for the question.

Answer / yesodha

3db value is the mean square value which is 70% of the
maximum value. the bandwidth found by using rms value will
be accurate

Answer / vasmatkar@hotmail.com

Mrudula at some extent you are correct can you pls make it
more clear

Answer / mrudula

3db implies 70%(o.7o7) of the power,i'e we r interested to
consider the bandwidth range from peak to 70% b'coz uptp
70% its reliable.hence 3db is called as half power freq

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