PRISM Forum - Message Replies


Topic: PRISM Questions and Answers
Topic Posted by: SRC (src_forum@alionscience.com )
Organization: SRC
Date Posted: Wed Jan 12 8:33:33 US/Eastern 2000
Topic Description: Welcome to the PRISM forum! Please feel free to post your questions and comments about the PRISM assessment software here.

Back to message list Show all replies About this forum

Original Message:

Posted by: Sue Hedrick (shedrick@advanced-control.com )
Organization:ACC
Date posted: Wed May 3 16:43:04 US/Eastern 2006
Subject: Resistor calculation
Message:
With regard to resistor calculations, how can I determine theta EC. I had thought that it was calculated using (storage temp - max operating temp) / resistor power rating. This gives me huge numbers, greater than 600 deg C / W. What should I be doing? Thanks, Sue


Previous reply
Reply:

Subject: Resistor Temperature/Temperature Rise
Reply Posted by: David Dylis (ddylis@alionscience.com )
Organization: System Reliabilitye Center (SRC)
Date Posted: Thu May 4 10:47:56 US/Eastern 2006
Message:
In lieu of actual information, I would recommend using the PRISM default. Appendix G of the PRISM User Manual includes defaults for resistor temperature rise. These defaults vary based on the type of resistor being used. Defaults are as follows:

Resistor, Fixed, Carbon Composition: Temperature Rise = 20
Resistor, Fixed, Carbon Film: Temperature Rise = 30
Resistor, Fixed, General: Temperature Rise = 30
Resistor, Fixed, Metal Film: Temperature Rise = 30
Resistor, Fixed, Network: Temperature Rise = 30
Resistor, Fixed, Thermistor: Temperature Rise = 0
Resistor, Fixed, Wirewound: Temperature Rise = 20
Resistor, Variable: Temperature Rise = 25
Resistor, Variable, Film: Temperature Rise = 25
Resistor, Variable, Non-Wirewound: Temperature Rise = 20
Resistor, Variable, Trimmer, Composition: Temperature Rise = 20
Resistor, Variable, Wirewound: Temperature Rise = 0
Resistor, Varistor: Temperature Rise = 50

If you have additional questions, feel free to contact me.


Reply to this message