DIY explained :
I bought a couple of wind-up dynamo LED lanterns in anticipation of the
winter power cuts. They have a 6volt charging socket but there is no
indication of the polarity on the case next to the socket and no instructions
as to polarity. My understanding is that the usual convention is that the
central pin is positive and the outer sleeve is negative on the charging
plug. Is this likely to be correct?

There is no convention, but more often than not tip is positive.


An adaptor was not included but I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip.

The only way to be certain is to disassemble and check. If the battery
is connected directly across the socket it might be possible to plug a
plug into it and check its polarity with a meter, but likely there will
be a diode in series to prevent wrong polarity, especially so if it is
unmarked.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk