04-24-2013, 08:37 PM
Yes, I have observed the same thing as Arran. Carbon comps seem to change slowly in value with age, regardless of use. The good thing is as they get older, the rate of change seems to decrease. So your "aged" resistors may actually be more stable than when they were new.
Allen Bradley carbon comps are very reliable despite their age. I very seldom have to change any which have been in use in equipment for decades. I have some which were bought new in the late 70's and although they all seem to drift up a few percent they are still within 5% of their marked value.
Other brands do not seem to fare as well. TRW/IRC and Stackpole come to mind as being very unreliable.
Allen Bradley carbon comps are very reliable despite their age. I very seldom have to change any which have been in use in equipment for decades. I have some which were bought new in the late 70's and although they all seem to drift up a few percent they are still within 5% of their marked value.
Other brands do not seem to fare as well. TRW/IRC and Stackpole come to mind as being very unreliable.