Re: AC spike go pass XFRM and regulator to reset CPU!!??

"Rodo" <noway@xxxxxxxxxxx> wrote in message
news:G2KQj.4106$zw6.2901@xxxxxxxxxxx
I was thinking about a ground loop with the scope but the circuit is being
powered by a 110VAC to 220 VAC transformer. I know the grounds are not
connected because I checked. I wonder if the transformer (110-to-220) is
not really isolated. I'll have to check this next week.

Such transformers are usually auto-transformers, i.e. they *don't* isolate -
it's just taps on a single winding.

Re your spikes while switching a disconnected fan - as Rocky said, check for
EMI suppression around the switch.

Steve


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