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'power supply - slightly [OT]'
1999\10\30@175959 by paulb

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Keith Causey wrote:

> Every Thrift Shop I ever go in has a full bin of orphaned wall warts
> of every conceivable description for prices ranging from $0.25 to
> $3.50.

 You mean "Every Thrift Shop I ever go in *had* a full bin"!

 Also - think "Garage Sales" - yeah, time consuming but fun.  I gave $5
yesterday for a shopping bag containing a Sinclair ZX Spectrum with
printer, many books etc.  One more for my museum collection. :)

 Another slight annoyance comes to mind - I can't remember where I
*put* my box of Plug Packs.  My collection of those includes several
with Euro and British pinouts (or indeed, pin-ins).  I need some sockets
for those.

Mark Willis wrote:

> I usually use DC 'wall warts' - Interesting!  I hadn't measured an AC
> one, I just let someone else use those, usually.  I didn't anticipate
> any real drop in voltage - guess I forgot about internal resistive
> losses inside the transformer, which is already part of why a DC
> plugpack "peaks" sans load.  Need a vacation here, obviously <G>

 General principle is: *All* transformers sag under load.  Small ones
do so a *lot*, and those in plug packs/ wall warts are *consumer*
appliances rated at unconscionably high temperatures.  It follows the
internal electrolytics dry out fast under constant use too.  You could
argue they are really not made for continuous all-day use, and if you
have a *serious* application you should under-rate them to 50% at which
point they must be over specified voltage.

 You're not going to use them to power logic circuitry without
regulation anyway.  It's not an option.  Your motor doesn't care whether
it gets 10V or 14V anyway (or if it does then *it* needs a regulator
too).

 Remember too that the mains itself varies a *lot*.

> or skip the fuse & let the plugpack's diodes blow if you must

 Even 1A plugpacks generally have diodes that can withstand the short-
circuit current quite well.  on less than 500mA devices I'd say it's
guaranteed the transformer will burn first.  You're using the
transformer winding as the fuse!  (Nowadays contains a thermal fuse.)

> I like the recent trend to try to use different plugs for different
> voltage ranges;  Even though it is a pain in terms of finding all
> those sockets, makes it less likely that someone will plug a 15VDC
> plug into their 4.5VDC device, then complain to the manufacturer about
> poor design quality <G>

 Eh?  First I've heard of this!  As far as I can see, it's a lost
cause.  20 years ago I tried for my own equipment to use 2.1mm coaxial
fittings for 12V and 2.5mm for anything less, but there has never been
any standardisation.  Worst of all are manufacturers who make the centre
pin negative.  I have been known to go so far as to re-wire internals
to correct for safety this foolish polarity on equipment.

>  Hoping Chris gets a new plugpack!

 200mA into one amp definitely won't go.  He'll need it.
--
 Cheers,
       Paul B.

1999\10\30@190724 by Mark Willis

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Paul B. Webster VK2BZC wrote:
>
> Keith Causey wrote:
>
> > Every Thrift Shop I ever go in has a full bin of orphaned wall warts
> > of every conceivable description for prices ranging from $0.25 to
> > $3.50.
>
>   You mean "Every Thrift Shop I ever go in *had* a full bin"!

<G>  I resemble that too!

>   Also - think "Garage Sales" - yeah, time consuming but fun.  I gave $5
> yesterday for a shopping bag containing a Sinclair ZX Spectrum with
> printer, many books etc.  One more for my museum collection. :)
>
>   Another slight annoyance comes to mind - I can't remember where I
> *put* my box of Plug Packs.  My collection of those includes several
> with Euro and British pinouts (or indeed, pin-ins).  I need some sockets
> for those.

I'd zing over & help look, but...  <G>

{Quote hidden}

Cheap to replace, tho <G>  I'm "spoiled", when growing up I always had
these 10-12 huge 12.6VAC 15A (or more) "can" transformers around - as in
about 15 of them - that I used, I think those things had about .02A
internal resistance, you could make NiCad wire glow pretty well off
that!  <G>  (If not turn it to plasma in short order.)  Those things
were about a foot on a side, mil surplus or some such I think, pretty
robust units.  Sure would power any project I cared to wire to them!
Tube filaments, no problems <G>

{Quote hidden}

A friend messed up & blew the diodes on a ComputerGate 12V 1A DC plugin,
running his AC/DC Television.  He replaced them with 3A Schottky's and
is still using the whole mess;  Hasn't blown up (yet.)  I think a
startup surge nailed the diodes?  Man, the things he'll do to not spend
$10 for a better power supply <G>

{Quote hidden}

Hate that too, I prefer center pin + as well.  I'll see if I can find
that table, anyone else seen that Barrel/Pin size vs. Voltage suggestion
table?  I'll keep an eye out.

> >  Hoping Chris gets a new plugpack!
>
>   200mA into one amp definitely won't go.  He'll need it.
> --
>   Cheers,
>         Paul B.

Mark

--
I do small package shipping for small businesses, world-wide.

1999\10\30@193708 by William Chops Westfield

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Manufacturers of any size who use wall-warts could improve their products
a great deal by simply providing a sticker that would fit on the wart and
identify WHICH product it belonged to!

:-(
BillW

1999\10\30@200651 by Mark Willis

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I just add that sticker myself (laser-print & use shipping tape, sticks
right on there nicely.)  Solves the problem, but I agree, should be
either a sticker, or just hot branded on there, before we get the
product.  I've been known to wire tie the power lump to the product <G>

 Mark

William Chops Westfield wrote:
>
> Manufacturers of any size who use wall-warts could improve their products
> a great deal by simply providing a sticker that would fit on the wart and
> identify WHICH product it belonged to!
>
>  :-(
> BillW

--
I do small package shipping for small businesses, world-wide.


'power supply - slightly [OT]'
1999\11\06@224056 by Jason Muhammad
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Just buy a Bigger label and write the Voltage and Amperage if using for
project power supplies, or what product it belongs to ZIP, EPROM eraser
(I wouldn't want to use my 24VAC wall wart with the PicStart Plus...)
The PIC would get Flashed alright...


Mark Willis wrote:
{Quote hidden}

--
Jason
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