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Spehro Pefhany Spehro Pefhany is offline
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Default Why do some manufacturers wrap the electrolytic capacitor that gets the hottest in a switching power supply in shrink wrap?

On Tue, 30 Aug 2011 15:47:21 -0500, the renowned Chuck

Extron has been doing this for years and of course it is the first
part to fail in their units. Smart Technologies Sympodium power
supplies, that they have contract built in China, fail in a year or so
for the same reason. Technicians and electronic engineers at my work
place can't think of a rational reason why these manufacturers do
this. This is pro gear where reliability is a great concern so it
doesn't seem to be planned failure mode. Thanks. Chuck

How about a photo?

There are two possible reasons that I can think of.
If it's a mains input filter capacitor, then it's likely for safety-
to beef up the very, very thin insulation on the capacitor body, so
they can get through the approvals process.

Otherwise, it could be to bolster mechanical support for the part so
it won't suffer failure form vibration, as an alternative to goop.

Best regards,
Spehro Pefhany
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