Peter, I'm not sure if I understand you well. Do you mean, that if my PTC has (for example) 1 ohm in normal operation I should assume that only 1 ohm is what is limiting the source power ?
Regards, Piotr ----- Original Message ----- From: "Tarver, Peter" <[email protected]> To: <[email protected]> Sent: Wednesday, October 11, 2006 5:22 PM Subject: RE: EN 60950-1 Limiting power to 15VA > Piotr - > > To expand on Ted's below (and quite correct) response, PTC's are treated > in such applications as fixed impedances, despite their current > dependent impedances. Thus, viewing the source from the load side of > the PTC's impedance is included (in a Thevinin sense) as a part of the > source impedance. > > Regards, > > Peter L. Tarver, PE > [email protected] > > >> From: Ted Eckert >> Sent: Wednesday, October 11, 2006 8:00 AM >> >> Hello Piotr, >> >> I recommend using clause 2.5 as guidance. This clause >> describes limited >> power sources for a different rating and purpose, but it can >> be used as >> guidance as to the proper limiting of any power source. >> >> It state that a power supply with a PTC will be considered >> limited if a >> positive temperature coefficient device is used, as long as >> the PTC passes >> the tests specified in IEC 60730-1, clauses 15, 17, J15 and J17. >> >> >> Ted Eckert > > CONFIDENTIALITY > This e-mail message and any attachments thereto, is intended only for use > by the addressee(s) named herein and may contain legally privileged and/or > confidential information. If you are not the intended recipient of this > e-mail message, you are hereby notified that any dissemination, > distribution or copying of this e-mail message, and any attachments > thereto, is strictly prohibited. If you have received this e-mail message > in error, please immediately notify the sender and permanently delete the > original and any copies of this email and any prints thereof. > ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS > NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform > Electronic Transactions Act or the applicability of any other law of > similar substance and effect, absent an express statement to the contrary > hereinabove, this e-mail message its contents, and any attachments hereto > are not intended to represent an offer or acceptance to enter into a > contract and are not otherwise intended to bind the sender, Sanmina-SCI > Corporation (or any of its subsidiaries), or any other person or entity. > _____________________________________________________________________________ > Scanned by Sanmina-SCI eShield > _____________________________________________________________________________ > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] > Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] > David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
