What will resist a frequency?

[nightlife]

 I also am wondering if a magnetic field is a frenquecies resistance.

[mapsrg]

Frequency is a wave or a pulse....and everthing has one.Depending on timing some waves travelling in different directions will cancel or partly cancel each other.Its all about phasing of peaks and troughs

[the_big_m_in_ok]

Quote from Hans von Lieven:
"a frequency can be cancelled by levelling the same frequency at it with a 180 degree phase shift"

>>"A band-pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range."
quoted from:
http://en.wikipedia.org/wiki/Band-pass_filter

A high pass filter stop let all but the higher frequencies than the target frequency through (let them pass).
The low pass filter will do the opposite.

Wikipedia should have examples of the math needed to figure the frequencies.


A band-stop filter will all allow all but a narrow band or frequencies through (notch filter).
The thread starter, nightlife, may have been looking for a band-stop filter.



http://ecelab.com/band-stop.htm

...had the basics for notch filters.