4 Jun
2005
4 Jun
'05
2:50 p.m.
By the way, the power supply, so far, has tested fine.
I'm going to look
for any ripple with the scope later today. I've never done that test --
should I DC or AC couple the scope for that test?
AC coupled. That's really what AC coupling is for -- you want to ignore
the steady DC level (of several volts) and look at the (hopefully) much
smaller AC ripple on top of it. To do that you need to turn up the Y
sensitivity on your 'scope, and unless you have a differential comparator
input or something, you won't be able to keep the trace on-screen with DC
coupling.
Don't worry too much about ripple on an S100 supply. The S100 supply is
not regulated -- the regulators are on each of the boards (the 8V input
is designed to be regulated down to 5V, etc). The regulators should take
care of small amounts of ripple on the backplane supply lines.
-tony