Scott, My first experience with this was in 1971 on a US military power supply. In reality it was a 1/8 Watt resistor of very low value and it would fuse with a little "pop", we called it a burp resistor. Being a carbon composition, and only 1/8 Watt it would quickly open with no smoke or fire and very little heating. It would generally just cracked open and even the circuit board was completely unmarked and no traces were lifted. It was a bit of a pain to change because it had to be soldered back in each time.
I just did a search of "burp resistor" (with quotes) on Google turned up nothing. Maybe that term is unique to the place where I worked at the time. -doug Douglas E. Powell Senior Compliance Engineer Corporate Product Compliance Advanced Energy Industries, Inc. Fort Collins, Colorado USA 80525 From: [email protected] [mailto:[email protected]] On Behalf Of Scott Xe Sent: Wednesday, July 18, 2007 8:49 AM To: [email protected] Subject: Carbon film resister acts as fuse to avoid temp rise I recently evaluated an audio product. During fault condition test, I short-circuited an electrolytic capacitor in power supply unit and found two small-value carbon resistors in series with a group of output windings of the isolating transformer and rectifier circuitry burned out in a couple of seconds. I repeated it several times and it worked reliably. I am wondering if this method is deem to be acceptable as a reliable means to prevent overheating. Any different comments about such means of protection? Thanks and regards, Scott - 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, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. - 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 ______________________________________________________________________
