what is the utmost important for ferrite EMI filter?

Status
Not open for further replies.
Y

yakex

Junior Member level 3
Joined
Nov 29, 2007
Messages
28
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,475
hi,
there are too many ferrite for emi filter from Murata, but what is the utmost important for the ferrite? the equivalent series resistance? the reactance? or the total impedance?
for example, if the effective radio frequency, then what I should is series mount a ferrite in the supply circuit to BLOCK the inference induced by the supply circuit?
thanks.
yakex
 

For most applications, a standard series "A" type would be suitable, for power supply a "P" type. For circuits dealing with UHF frequencies and it's harmonics, "GHz Noise Suppression" H series and "High GHz" G series may be interesting.

All ferrite beads have an almost resistive impedanz above a certain frequency, in this region resistance and total impedance are effectively equivalent.
 

FvM: Thanks for your reply.

what you said is the general rules for product selection, and it is helpful to me.

But what I want to learn is whether I should select a ferrite of large resistance at the frequency range of interest, in order to block the external interence?

Thank you again.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…