design of L-C filter?

Answer 1

I guess with what you asked this is what you need???

Cut-Off Frequency
F = 1/(2*PI()*SQRT(L*C)
Characteristic Impedance
Z = SQRT(L/C)

circuitcalculator.com/lcfilter.htm

here is where i got it...If you need to know how it works ask again....Good luck from the E....

Answer 2

Typically, it's an inductor (L) and a capacitor (C) in series with an oscillating voltage source (a signal generator). The output is taken as the voltage across either the inductor or the capacitor, depending on the purpose.