Capacitor aging

[anonemus]

Guys, apologies if this is unrelated. I keep reading about "capacitor aging", what exactly does this mean? Is this where some say a PSU's performance/efficiency degrades by 10% per year?

[370forlife]

Capacitors will start to loose their capacitance and their ESR starts to raise slightly (in the case of a good brand,) but this usually takes years and years (I still have plenty of 10 to 12 year old Rubycon and UCC caps that are well in spec)

Apparently aging capacitors pull more current somehow? Doesn't make sense. Really doesn't happen. Don't worry about it.

[Travis]

Guys, apologies if this is unrelated. I keep reading about "capacitor aging", what exactly does this mean? Is this where some say a PSU's performance/efficiency degrades by 10% per year?

As it ages the filtering performance drops slowly and the self-heating on capacitor rises a bit.

[anonemus]

One reason I asked is I usually buy PC components from the used market. What are the practical tips in buying a used PSU? Should I avoid units over a year/two/three years old?

[370forlife]

If you are going to buy something 3 years or older you may want to start looking at the caps, make sure they are all fine. Other than that just make sure they are a reputable brand.

[jonnyGURU]

If you know enough to apologize for taking a thread off topic, you probably should just go ahead and start a new thread. ;)

[anonemus]

If you are going to buy something 3 years or older you may want to start looking at the caps, make sure they are all fine. Other than that just make sure they are a reputable brand.

Ah, I see! Now I have to learn first the very basics. Must admit I only have a vague idea about electronics. I guess I'll back read more. Thanks, 370!

If you know enough to apologize for taking a thread off topic, you probably should just go ahead and start a new thread. ;)

I was about to start a new thread when I noticed this is a new thread! Thanks for the assist, Mr. Guru :)

[TheLaw]

For instance. I pulled a 220uF rated electrolytic from a 10 year old power supply and tested it on my multimeter, and read 169uF which is about 50uF lower than what is rated at. However, capacitors have tolerance ratings which mean how far the actual value can be from the value printed on the label. So its only about 5uF out of that range.

But still much less than what it's rated to hold.

[shovenose]

Thelaw, what brand cap was that?