Path: utzoo!news-server.csri.toronto.edu!rutgers!gatech!ncar!elroy.jpl.nasa.gov!swrinde!zaphod.mps.ohio-state.edu!samsung!spool.mu.edu!uunet!mcsun!ukc!warwick!esupg From: esupg@warwick.ac.uk (Andrew Bargery) Newsgroups: sci.electronics Subject: Re: NEGATIVE VOLTAGE? Message-ID: Date: 13 Mar 91 14:13:49 GMT References: <1991Mar8.140031.20095@uncecs.edu> <1991Mar12.174440.26009@tc.fluke.COM> <2RH&P6_@warwick.ac.uk> Sender: news@warwick.ac.uk (Network news) Organization: Computing Services, Warwick University, UK Lines: 21 Nntp-Posting-Host: clover sorry to follow my own article up, [blurf about connecting PSUs in series] The PSUs that you use must be of the 'Floating Ground Type'. That covers the majority of lab. PSU you are likely to come accross. They can (usually) be identified by having separate +, - and Gnd terminals. If there is not a separate Gnd terminal, it is common to find the - terminal internally connected to Gnd. In this case, you obviously can't reference the +ve terminal to Gnd also! > I don't think you can use this method if > you are using switch-mode power supplies. The type I was thinking of have the -ve terminal (0v) connected (internally) to Gnd. I guess you could also have floating ground SMPS units. ------------------------------ esupg@uk.ac.warwick.cu ----------------------- DISCLAIMER: Andrew University of Warwick, Coventry, UK. Bargery 154 Brunswick St, Leamington, CV31 2ER, UK. I plead the 5th... vox : +44 926 881264