17 Aug
1999
17 Aug
'99
11:22 a.m.
Hi Tony and all,
At 12:28 AM 8/18/99 +0100, you wrote:
In many cheap wall-warts, the primary wire is undersized and is the default
fuse link. Is is scramble wound without much/any added insulation between
the start of the winding and the rest of the coil, so it being the fuse is
pretty common.
This practice may be worse for wall-warts for charging NiCd's, where the
smaller wire size provides the current limiting, especially with one or
more shorted cells.
-Dave
Also, if
using a packaged 'OEM' supply unit, one is spared the
onus of compliance with a bunch of Regulatory Agencies... UL, FCC,
CSA, ISO..... this is the reason a lot of products came with
'brick' or 'wall-wart' power units... someone else has already
It's just a pity that those wall-warts in general are _not_ safe in my
opinion (to the extent that I generally replace them with homebrew PSUs).
Most of them have no internal fusing or thermal fuses (at least in the
UK).