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Old 04-01-2012, 10:17 PM
Karls48 (Karl)
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Karls48 is offline
Join Date: Jan 2006
Location: Sydney
Posts: 753
Originally Posted by JohnH View Post
Replacement PCB arrived today - fitted - it works, great service from SBig.

And a word of warning about LAB type power supplies - these often allow the ground to float - that is the -ve pole is not a true ground (earth). This is done, I think, to reduce noise.


In my case the difference between +ve and -ve was 13.8V the difference between -ve and earth was 24.7V baaad.

Bottom line is don't assume - check.


John, as ex engineer that worked with PS for long time - most of power supplies are floating - ea 0 volts is not tied to the Earth

Last edited by Karls48; 04-01-2012 at 11:43 PM.
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