I was going through the application note AN-1368 regarding Ferrite bead selection and design.
I understand the inductive region lies on the left side of the X=R point in the Impedance vs frequency graph.
But how is the capacitive region determined?
The above shown picture is taken from the application note. Clearly inductive region is left side of the Z=X point.
How is the capacitive region determined.
Thanks in advance
Yes inductive region is below the point where inductive reactance is equal to R. As for the capacitive region, it is the frequency range after the absolute value of capacitive reactance is equal to R. The capacitive reactance goes negative as you can see in the graph below.
Yes. You are correct. Can you explain how to find the frequency where the absolute value of capacitive reactance equals R. I am not undersanding how this particular area is being considered as capacitive region..
Most of the ferrite bead datasheet just shown the positive impedance that is why it's difficult to know where the capacitive region starts or where the crossover for the R and Xc (as Xc is negative) unless you ask the manufacturer that specific information or you perform the impedance measurement yourself like the one we have below.
This plot is measured from our lab.
The purple trace shows the absolute value of X to make the Xc positive and see the crossover of the X and R.
The capacitive region is after crossover of the R and the Xc where the capacitive reactance starts to dominate the overall impedance Z (the R component starts to drop) which can be seen as the light blue shaded region at the figure added by Aldrick.
Thanks and regards,
Thanks Jeff, Got an idea about the graph and how to get the capacitive region.
I will contact the manufacturer for the same.