[SI-LIST] Re: LED with series bead

Beads sometimes get applied to front panel LEDs, switches and such in 
the belief that this will limit EMI radiation and/or ESD 
susceptibility.  You can decide for yourself if you think, there is a 
lot that a ferrite bead is going to do that a 100-300 Ohm current limit 
resistor doesn't already do.

Steve.

 
z46147 wrote:
> Content-type: text/plain; charset=gb2312
> Content-transfer-encoding: 7BIT
> Hi all,
>
> I also want to know root cause of this application.
>
> Any thought on it would be appreciated.
>
> Best regards.
>
> Zhuyongfa
> HUAWEI TECHNOLOGIES CO.,LTD.  
>
>
> Address: Huawei Industrial Base
> Bantian Longgang
> Shenzhen 518129, P.R.China
> Tel:+86-755-89653025 
> Fax: +86-755-89650731
> E-mail: zhuyongfa@xxxxxxxxxx
> www.huawei.com
> -------------------------------------------------------------------------------------------------------------------------------------
> This e-mail and its attachments contain confidential information from HUAWEI, 
> which 
> is intended only for the person or entity whose address is listed above. Any 
> use of the 
> information contained herein in any way (including, but not limited to, total 
> or partial 
> disclosure, reproduction, or dissemination) by persons other than the 
> intended 
> recipient(s) is prohibited. If you receive this e-mail in error, please 
> notify the sender by 
> phone or email immediately and delete it!
>
>   ----- Original Message ----- 
>   From: Vijay Anand 
>   To: si-list@xxxxxxxxxxxxx 
>   Sent: Tuesday, November 06, 2007 6:30 PM
>   Subject: [SI-LIST] LED with series bead
>
>
>   Dear All,
>   In our design we connect a bead in series with LED while driving from an 
> I/O pin.  I dont know why this bead is connected ( still series resistor is 
> there for current limiting). Is there is any relation with EMI? Kindly do the 
> needful.
>   With Regards,
>   Vijay Anand. G
>   ------------------------------------------------------------------
>   To unsubscribe from si-list:
>   si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
>   or to administer your membership from a web page, go to:
>   http://www.freelists.org/webpage/si-list
>
>   For help:
>   si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
>   List technical documents are available at:
>                   http://www.si-list.net
>
>   List archives are viewable at:     
>   http://www.freelists.org/archives/si-list
>   or at our remote archives:
>   http://groups.yahoo.com/group/si-list/messages
>   Old (prior to June 6, 2001) list archives are viewable at:
>     http://www.qsl.net/wb6tpu
>     
>
>
>
> -- Binary/unsupported file stripped by Ecartis --
> -- Type: image/jpeg
> -- File: outlook_huawei_logo_en.jpg
>
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> http://www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List technical documents are available at:
>                 http://www.si-list.net
>
> List archives are viewable at:     
>               http://www.freelists.org/archives/si-list
> or at our remote archives:
>               http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
>               http://www.qsl.net/wb6tpu
>   
>
>
>
>   


-- 
Steve Weir
Teraspeed Consulting Group LLC 
121 North River Drive 
Narragansett, RI 02882 

California office
(408) 884-3985 Business
(707) 780-1951 Fax

Main office
(401) 284-1827 Business 
(401) 284-1840 Fax 

Oregon office
(503) 430-1065 Business
(503) 430-1285 Fax

http://www.teraspeed.com
This e-mail contains proprietary and confidential intellectual property of 
Teraspeed Consulting Group LLC
------------------------------------------------------------------------------------------------------
Teraspeed(R) is the registered service mark of Teraspeed Consulting Group LLC

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List technical documents are available at:
                http://www.si-list.net

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
  

Other related posts: