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Ferrite Bead symbol and reference designator

Printed From: PCB Libraries Forum
Category: Libraries
Forum Name: Schematic Symbols
Forum Description: [General or a CAE specific issues / discussions]
URL: http://www.PCBLibraries.com/forum/forum_posts.asp?TID=2271
Printed Date: 15 Jun 2019 at 3:30pm


Topic: Ferrite Bead symbol and reference designator
Posted By: bnoel
Subject: Ferrite Bead symbol and reference designator
Date Posted: 20 Dec 2017 at 8:29am
Hello,

I am seeing some conflicting information online regarding Ferrite Beads.  I see some documentation that shows the schematic symbol for a Ferrite Bead as an Inductor with a reference designator of L and other documentation that shows the symbol as in the inserted image with the reference designator of FB.  

What is the definitive symbol and ref des?



Replies:
Posted By: Tom H
Date Posted: 20 Dec 2017 at 8:45am
Here is a list of common ref des for the past 30 years - 
https://www.pcblibraries.com/forum/common-pcb-reference-designators_topic728.html" rel="nofollow - https://www.pcblibraries.com/forum/common-pcb-reference-designators_topic728.html
 
They have the same electrical function:
 
"L" covers Inductors, Beads, Ferrite Beads,
Chokes, Common Mode Chokes and all parts related to the function of an electric
or electronic circuit that possesses inductance used in order to filter common
mode electromagnetic interference (EMI) currents without de-rating under high
currents and without causing signal degradation. Or, the geometry and
electromagnetic properties of coiled wire over the ferrite bead result in an
impedance for high-frequency signals, attenuating high frequency EMI/RFI
electronic noise.

I guess you can use FB for Ferrite Bead. Sounds good to me.



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Posted By: tgrodnicki
Date Posted: 21 Dec 2017 at 12:28am
Originally posted by Tom H Tom H wrote:

Here is a list of common ref des for the past 30 years - 
http://www.pcblibraries.com/downloads/temp/Reference_Designators_7537645.pdf " rel="nofollow - http://www.pcblibraries.com/downloads/temp/Reference_Designators_7537645.pdf  ;
"Error 404: Page was Moved!"

In document from 2004 created by PCB Libraries and titled Standard Reference Designators "FB" stands for Ferrite Bead.
I followed standard from this publication.

In document from 2009 created by PCB Matrix and tltled IPC-7351B Naming Convention for Standard SMT Land Patterns in section PCB Matrix Naming Convention for Non-Standard SMT Land Patterns land pattern name for Ferrite Beads is FB_Mfr.'s Part Number.

Current version of lattter document does not have section for non-standard patterns.



Posted By: Nick B
Date Posted: 21 Dec 2017 at 2:26am
I don't know where the temporary link came from, but I modified Tom's post with the proper link.
Please try again...

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Posted By: LarryJoy
Date Posted: 28 Aug 2018 at 2:29am
The IEC 60617 graphic symbol for a Ferrite Bead is shown in IEEE 315A, Clause 6.2.11 as follows:

In addition the class letter to use in a ref des is E. See IEEE 315, Clause 22.4.




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