On Sun, 2007-05-27 at 13:11 +0100, Peter Clifton wrote: > On Sun, 2007-05-27 at 08:02 -0400, Randall Nortman wrote: > > So now I have to figure out if I really care about those >60Hz spikes, > > dips, and noise. I am thinking not, so transformers should be just > > fine. Then again, the reference designs for these Analog Devices > > chips just put a resistor divider between hot and neutral and feed it > > straight in without isolation. They use neutral as DC circuit ground > > and derive power from the hot line, so the whole circuit is tied to > > mains without isolation. If I did that, I would of course have to > > make sure that the digital interface between my measurement system and > > the PC that captures the data is isolated, which is pretty easy. Any > > thoughts on that setup? > > Not a bad setup, but like you say, needs careful attention to isolation > and insulation at appropriate points. > > Be careful with resistors, they have a voltage rating, so for mains work > you may need more than one in series (in the high side of the divider) > to avoid them failing open-circuit. > > Regards, > > Peter Clifton ... see also http://www.edcheung.com/automa/power.htm > > Greg Cunningham <[EMAIL PROTECTED]>
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