does anyone know the formula for band pass filters.
Well, if it is the ideal RC filters case, then is just the combination of the low pass and the high pass. I can't remember the formula. I think you can also make CL band pass filters. Which case are you interested in?
There's no real Formula per-se, as there are many types of filters.
Active,passive, wide band,narrow band, variable q, It all depends on your application. Do you know what you want or do you have an application in mind?
There are some dozen different kinds of filters used in industry, and, if none of them suit you, you can make your own.
the formula i need is for a passive band pass filter
Blair , I'm not trying to be critical, but you've posted 3 times in relation to passive filters and alluded to thier importance to your education.I believe You're looking for answers rather then help understanding the method.If you cannot grasp the basic ideas and
math of this material and seek only answers to homework, you will surely be lost when it comes to much harder concepts. So do yourself a favor learn the math , buy a casio scientific calculator one that has automatic decimal translation ( I.E push the k button for Kilo, the m button for micro) they sell for < $20 programmable is better you just call up the routine and plug in the variables.
In direct answer to your question ...RC or RLC? An RC is basically two series t filters with more components then an RLC.
You need to look into two-terminal-pair networks analysis to get a paticular formula for your circuit. The best way I've found in designing a filter is to do a little trial and error with the components.
Separate names with a comma.