DIYbanter - View Single Post - What is the expected lifetime for an electrolytic capacitor?

mike

wrote:
On 22 Mar, 12:17, wrote:

I'm wondering what the expected lifetime is for electrolytic
capacitors in recent years. I'm sure temperature and operating
voltage play a role.

It varies hugely. Some have lives of thousands of hours, some of over
a century.

Ripple current also affects them.

Capacitors failng to do the job are often not down to bad caps, but
rather bad design with insufficient margins.

I'm no fan of replacing good caps with other good caps that are just
as likely to fail, but if you've found bad caps in there then any
others the same make are probably best replaced.

NT

I recently came to a sad realization...I'm gonna have
to quit buying (newer) old equipment with the expectation of fixing it.

Was an HP LCD monitor. The cap on the output
of the swticher had failed putting 20V pulses on the
5V supply line. Fixing the cap didn't help 'cause
the 20V had taken out the control processor and who-knows-what-else.

Switcher designs I've seen use the cheapest available components and
have no prevision to limit voltage when the output cap opens...and given
the extreme stress placed on it by the switcher, it will...eventually.

I predict this time bomb is gonna have a profound impact on the
used equipment market.

mike

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