Hi,
some Switching Power Supplies come with some electronic components partially covered by a white glue called "Varnish".
Does anybody know what Varnish is and why they use it all around in Power Supplie?
Thanks in advance, Enrico Migliore
Flyback Power Supplies: Varnish question
Apr 29, 2011
3 Replies
I don't think that's the correct translation. Somtimes it's RTV silicone, but I think there are other formulations of adhesive used.
There's often goop of some kind added to prevent premature failures due to mechanical vibration- typically on physically large inductors or capacitors.
I believe that for high-voltage supplies, varnish (or humidi-seal) can decrease the chances of arcing -- but I dunno, never having done anything with a circuit that had more than 800V on it.
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
Varnish is usually the red coating on the Transformer windings. It is there as an isolation. If the white looks and feels like silicon, it is.
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