At high frequencies sometimes ferrite beads are used instead of inductors as normal/differential mode filters. I draw Figure 1 and Figure 2 below showing LC and Ferrite bead C differential filters:
Let’s assume we want to quantify the voltage attenuation at 1MegHz. For. Figure 1 case I can write:
Vout / Vin = Xc / |Xc+Xl|
where Xc is the capacitive reactance and Xl is the inductive reactance. But as you see the denominator is actually the vectorial/phasor sum. It means at particular freq. there will be resonance when Xc=Xl and current will reach maximum ect.
What if we use a ferrite bead instead of an inductor as in Figure 2; will the denominator be vectorial/phasor sum or scalar sum? Imagine the ferrite bead impedance is given as 100 Ohm at a particular freq. and by chance the Xc is also 100 Ohm at that freq.; in that case will the denominator be zero or 200 Ohm? Or will it be sqrt(100^2+100^2)?