SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and Answers
Topic Posted by: Reliability & Maintainability Forum
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by: Richard Smith
Date posted: Tue Mar 18 10:22:38 US/Eastern 2003
Subject: CHR Capacitor Shelf Life/Aging
Can anybody please refer me to a source of information on Capacitor Aging and Shelf Life (aging mechanisms and reliability of older components).
I am particularly interested in CHR capacitors (fixed, metallized, plastic film dielectric).
Thanks in advance.
Subject: Capacitor Non-op Degradation
Reply Posted by: BWD
Date Posted: Wed Mar 19 10:44:44 US/Eastern 2003
All components have degradation due to corrosion over time when in an uncontrolled non-op condition. Inaddition, electrolytic capacitors have a degradation mechanism due to loss of electrolyte by means of vapor transmission through the end seal. The rate of loss is a function of the storage temperature. Film capacitors do not have this degradation problem, so all you need to be concerned with is the corrosion. Sealing the parts or units in a bag that is back filled with dry nitrogen is one way of controlling the environment. By the way, electrolytic capacitors can be re-aged every two or three years by slowly applying voltage with a resistor in series.