In passive filters, what is the difference between band pass and stop band filters?

Question

What are the ripples?

Answer 1

A passive bandpass filter will have either or both:

1) Cap in parallel with coil, in parallel with source and load (which will short out-of-passband signal to ground), or

2) Cap in series with coil, in series between source and load (which will appear as a high resistance to signals not within the passband).

Either of these will tend to reject frequencies that are not close to the resonant frequencies of the LC combinations

A bandstop filter will have the opposite, either or both:

1) Cap in series with coil, in parallel with source and load, or

2) Cap in parallel with coil, in series between source and load,

Either of these will tend to pass only frequencies that are not close to the resonant frequencies of the LC combinations

The reason for the opposite configs is because a series resonant circuit has minimum impedance to the signal frequency, whereas a parallel resonant circuit has maximum.

The ripples in response are a result of having multiple resonant LC combos having slightly different resonant frequencys. Filters are designed this way in order to have a wider, flatter passband yet also have sharper drop-off out of passband.

Answer 2

band pass filters only let signals thru within a certain range eg 1-2khz stop band filters do the reverse they stop all signals in the range specified. Depends what u r on about with ripples, cud be in psu's, variations in voltages that are smoothed out with capacitors also could be voltage spikes

Answer 3

Band pass: stops everything except one specific band

Band stop: passes everything except one specific band

Answer 4

"Pass filter" ? no such thing. "high band-pass" no such thing either. There are low pass, high pass, band pass, and band reject filters. What they do is obvious from the name.