3 Sep
2014
3 Sep
'14
12:15 p.m.
Came across something else last night.. are the power transformers (in B
model PSUs) known to be a bit on the leaky side?
I was running the machine on a non-grounded outlet, and noticed quite a bit
of tingle along the metal chassis. Hooked up an instrument and read around
90uA of 60Hz AC leakage current between chassis and the cold-water pipe
ground circuit for my ESD protection scheme. (actually an iron radiator,
Is there a amins filter circuit in this machine? This would often involve
capacitors between the AC lines and the chassis/gorund, so if the chassis
is not conencted to ground yo can draw a currnet form the live ('hot')
side of the mains thoough one of the capacitors to the chassis and then
to gorund.
Note that htis does not mean the capacitor is leaky. A capacitor will pass
an AC current, which is what the mains is.
-tony