I remember a serious problem when slivers got between traces and shorted them out. Very hard to spot and required reworking every board. Painful.
However, now with computers, you can make even bigger mistakes much faster!
Yes, sometimes those were from poorly heat-treated tin-coat overhand breaking after etching, it could still happen now.
--
Thanks,
- Win
Winfield Hill wrote in news: snipped-for-privacy@drn.newsguy.com:
Way back then it was usually from bad art and bad QA (not) looking at the art before sending it to production.
Not because they want to be different, because they don't want to break surveying.
"Any data expressed in feet derived from and published as a result of geodetic surveys within the United States will continue to bear the following relationship as defined in 1893 : 1 foot = 1200/3937 meter"
Notice the date they defined this formula!
Rick C.
I still use Gaussian units for electromagnetics. (Gaussian is a rationalized version of the CGS ESU system.) My fave EM textbook is Jackson's second edition--for the third he switched to SI, the dog. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Ouch!
With 4 * pi hidden into the units at random ...
-- -TV
When you're doing theory, it matters a lot more that the equations are simpler. You can convert to SI trivially at the end of the calculation.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
I'm reading.. well slowly chewing.. 'atomic physics,...' by D. Budker
He uses cgs because he finds it easier. Well, he also sets h-bar = 1 sometimes...
George H.
*I like this book, but it's graduate level physics.. and I find myself going back to lower level sources to review things.... I don't remember the eigen values of the (L dot S) operator, with hydrogenic wavefunctions, for instance. GH
Just apply a lot of current!
We make very few mistakes on PC boards. We don't prototype. Rev A is built by production and we expect to sell it.
We don't get PCB shorts either; all board are bare-board tested. One short or open instantly disqualifies a PCB vendor.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
We use ENIG, gold over nickel, and we don't see shorts any more.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
them
er!
When your average new-product development time is two weeks - as John Larki n has told us is his norm - there's not a lot of difference between success ive printed circuit layouts. More adventurous development does offer more o pportunities for things to go wrong, but careful design reviews at every st age can catch quite a lot of bugs.
If they claim to do bare-board testing before they ship it certainly ought to.
It's nice when you have enough suppliers to let you be that rigorous.
-- Bill Sloman, Sydney
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