On Tue, 05 Oct 2004 23:09:32 -0500, David Maynard wrote:

keith wrote:

On Mon, 04 Oct 2004 22:33:31 -0500, David Maynard wrote:


keith wrote:


On Mon, 04 Oct 2004 03:21:58 +0000, daytripper wrote:



On Mon, 04 Oct 2004 01:50:54 GMT, "NSM" wrote:



"larrymoencurly" wrote in message
ogle.com...
...
| National Semiconductor says that each USB port must have a 120uF or
| larger ....................................... But my USB card has
| only a 100uF aluminum capacitor and maybe a ceramic capacitor in
| parallel for this....

Close enough!

Except the tantalum cap would have much lower esl & esr figures than an
aluminum cap, making it more effective.

otoh, tantalums can have a brilliant failure mode ;-)


So do engineers when they're bringing up a system where all
of the tantallums were inserted backwards. You want to see fireworks!
(well,it was 25 years ago - I've mostly recovered and the tinninus
isn't so bad. twitch)


LOL. Yeah, I'll bet.

You get a similar result plugging non keyed circuit boards into a vertical
card rack 180 degrees reversed.


A good reason to hang the mechanical designers by the short things. One
*should* have to go to great lengths to pluch dangerous things in
backwards. In this case they did just that. ...and even complained about
how hard it was!


Hehe. Well, with the one I mentioned it was an experimental prototype built
by the design engineer.

....even this design engineer knows how to key a connector. ;-)

--
Keith