Mike Harrison wrote:

This is normal for any non-earthed mains operated device with a metal case

aye, more or less;

- it's capacitive coupling of the mains through the transformer

pickyif it's through the transformer it's scarcely capacitive, is
it/picky It is usually capacitive coupling, either through
interference-suppression capacitors in the mains input filter (but in
that case the case *should* damn well be earthed, so you won't feel any
juddering/humming/whatevering: and if you can, it could indicate a
broken earth conductor in the supply lead (bad) or at the wall socket
(worse); or, in the case of Class-II ("double insulated") kit, designed
not to need an earth connection, capacitive coupling through stray
capacitances as mains wires or switched-mode PSU wiring comes close to
the case. VCRs and TVs additionally may have small-value capacitors
which couple the mains feed to the outer core ("earth") of their aerial
connectors - for these, you can sometimes get rid of the tingle by
reversing the mains input lead if it's one of those figure-of-8 leads.

.. Very low current and not harmful.

Not harmful by itself, no, but in some cases an indication of the case
not being earthed when it should be. In the OP's case, it's *not* that
for his Palm 3, but possible for the DVD player, depending on whether it
takes a 2-wire feed from the mains or a 3-wire one...

Stefek