17 Sep
2007
17 Sep
'07
11:19 p.m.
I find that
very hard to believe. I would be suprised if most (if any)
signal connecotres met the approvale requirements for a mains connector.
You got me curious, so I just ran a search on Farnell's database for DB25
connectors rated to 500V; it coughed up 60 different ones.
I can't think of an example where I've actually seen it done with D-types, but
I've certainly come across it on telecomms stuff before using DIL-type card
connectors (what I've always called 'euroconnectors', but I'm not sure
what
the official term is)
DIN41612 connectors? The sort of think used for Nubus cards, for example?
There are many variants of those, incluiding ones iwth widely spaced pins
(0.2"?) for mains work. That Philips machine you gave me has one on the
SMPSU board for that purpose.
I've seen PCBs with a mains DIN41612 connecotr and a signal DIN41612
connector alongide each other, but I've never seen a board that puts live
mains on the same connecotr as low-votlage logic signals.
I bought one of those wall warts with a range of
interchangeable connectors
when I was in the US last. Seemed like a good idea at the time; the connectors
were reversible so that you could swap polarity just by changing the connector
through 180 degrees on the cable, not to mention that it came with about ten
different sizes of connector. (the kids were getting through batteries in toys
with lightning speed :-)
It was only when I took the packaging off that I discovered the flaw: the
terminals at the end of the cable are marked for polarity - but there are *no*
markings on the interchangeable connectors which give an indication of which
of the two pins goes to the connector's ring, and which goes to the tip.
Without any test gear it's random as to the polarity of the plugged-in connector.
Argh!. How about 'buzzing out' each 'end' with an ohmmeter to determine
which pin is the tip and which the sleeve, and then marking the 'tip' pin
on each 'end' with, say, Tipp-Ex.
The box of 'ends' I bought at Maplin each have a little diagram on 2 of
the sides of each tip showing the polarity (opposite polarites for the 2
diagrams on each dip, of course). The cable-mounted socket has an arrow
on one sidem and I wired it so that points to the apporpairte diagram
when the tip is plugged in. That maant the wire wit the the tracer stripe
on it wen to the -ve side of the bench supply and the plain wire to the
+ve. Oh well...
-tony