Godamned 0603

Your label of "Euro-centric" would seem to be rather US-centric. It's pretty much us against the world on this one. I do see some data sheets that seem to treat inches as the obligatory technical concession to the US. Otherwise it is metric all the way.

It's a damn good thing they had already developed metric measurements for electricity by the time things got rolling. Otherwise we would be the only country left measuring resistance in barley corns and electrical potential in hands, requiring a conversion factor of 3.92118E-4 to get current flow in ounces of silver per fortnight.

Lasse Langwadt Christensen snipped-for-privacy@fonz.dk wrote in news:4ecce2c8- snipped-for-privacy@googlegroups.com:

I always used the metric designations and perform my purchases and my layouts in metric as well. Much easier. I have been 'metrisized' since the '70s.

Jeroen Belleman snipped-for-privacy@nospam.please wrote in news:sunu9q$1l2u$1 @gioia.aioe.org:

Anti-metric much? You anti-mask as well?

I would hope you'd understand the difference in changing nomenclature and changing measurement systems. Caliber is not an actual measurement of anything, rather a nominal use. Same as 12 inch wafers or a 19 inch rack cabinet. I guess something on a 19 inch rack cabinet is actually 19 inches, but in reality, it's just a name we use.

Yeah, whoever does a thing first gets to name it and set the measurements, but they can get changed. You still see references to angstroms in measuring wavelengths. Doesn't mean it isn't stupid.

In the US there is no conversion process. We decided to convert and then decided not to. That's on us. I believe we lost a Mars lander because of that. I'm sure there have been many, many other issues as well. I know that's why the Navy won't convert from yards to meters for targeting. The two measurements are close, but they are too concerned about what happens during the switchover which would take some decades. Opps, I didn't mean to hit *that* ship!

With feature sizes on PCBs using fractions of thousandths of an inch, there isn't much reason to stick with it. Get rid of the confusion and convert. Rip the band aid off and be done with it. But PCB manufacturing is one of the least progressive areas of electronics in terms of standards and modernization. They have tried on more than one occasion to incorporate Gerber files into a standard that would provide much more information. I think those attempts have only met with limited acceptance. Is it because there are too many competing standards from different companies?

Joe Gwinn snipped-for-privacy@comcast.net wrote in news: snipped-for-privacy@4ax.com:

Yep.... for many many decades.

If I say a number in 'mils' to an engineer in the US, he or she automatically knows I refer to thousandths of an inch.

Well.. maybe Larkin is an exception to that. He still thinks you are supposed to dip in a vapor phase cleaning tank.

Lasse Langwadt Christensen snipped-for-privacy@fonz.dk wrote in news: snipped-for-privacy@googlegroups.com:

And a conscious mental effort on the part of the person claiming to be performing engineering tasks.

In the US, machinists usually say thou and engineers most often say mils, both meaning 0.001 inches.

Surprisingly, some big aerospace companies still use pounds and slugs and BTUs and things. Creeps me out.

The Gimli Glider was about confusing gallons with liters.

Many decades ago I bought some stripboard for a prototype. It was 2.5mm pitch, which I assumed was really meant to be 0.1".

It was in fact 2.5mm as claimed, and the pins on my 40 pin DIL processor were well bent, like a man trying to fit into too small shoes.

I do have a lot of sympathy for some 'imperial' units. For example, I have a set of scales in the kitchen with both metric and imperial weights. The imperial weights have no duplicates. The metric weights have two of 200g and two of 20g. Yes, I realise that's because there are 2^4 ounces in a pound. Likewise, inches in halves, quarters, eights, sixteenths etc - very convenient and easy to eyeball.

We need to make 16 the default number base. You know it makes sense.

Hard to count on the fingers?

I knew a woman who had six fingers on each hand, all fingers looking and working normally. But she didn't even attempt to get to eight fingers per hand.

Joe Gwinn

I would hope you'd understand the difference in changing nomenclature and changing measurement systems. Caliber is not an actual measurement of anything, rather a nominal use. Same as 12 inch wafers or a 19 inch rack cabinet. I guess something on a 19 inch rack cabinet is actually 19 inches, but in reality, it's just a name we use.

a 19" rack enclosure is 19" wide including the "ears"

in the case of 7.62mm it is land to land diameter of the barrel, the bullet is bigger

Mars Climate Orbiter likes it! ;) Best regards, Piotr

Not entirely, decibels still haunt the landscape. Why would I write 60dB if I mean 1e3 relative something?

Best regards, Piotr

Hard for kids to learn the addition and multiplication tables.

Most DEC computers were octal, even the 16-bit PDP-11. I can still assemble some octal instructions from memory.

Base 12 has been proposed to replace 10.

There must be some FOR loop in our DNA that wraps around a subroutine called FINGER. Maybe one base pair is the index.

What's amazing is that the 6th finger actually works, has veins and nerves and muscles and tendons and stuff.

I didn't know that. Thanks for the heads up. I have a design I need to check (again) before it goes to JLC.

Actually, there was a time when I was disassembling PDP-11 machine code manually, and one soon learned the common opcodes.

Well, it's mechanistic, but way more interesting than DO loops: Sonic Hedgehog and Homeobox genes, specifically HOX genes. The literature is immense. Here are some summary articles.

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Yes, extra fingers are often vestigial, and people usually have them removed surgically. But not in her case. The only problem, aside from an occasional quizzical look, was that regular gloves didn't fit.

Joe Gwinn

Somehow, I managed to connect an imperial 0603 resistor to a metric 0603 pad. The component is skewed, and its top surface is at a 45 degree angle to the board (!), but it is connected.

I don't expect that it's something I can repeat though.

Sylvia.

No, I think the question was why was a size code needlessly duplicated? The numbers are only an approximation to the size anyway. Whichever came second could have been named 0604, without any other impact whatsoever.

Sylvia.

Then there are the sideways caps, like 0306.

It's not about first or second. The convention is to name the part by its size. If you are using metric the size will be named by the approximate metric values.

People need to learn this is a metric world. Do you really think the rest of the world is bound by the mistakes made in the US fifty years ago?

While anyone can make a mistake, in reality, this is your mistake. I sympathize with your problem, but it is not the responsibility of the people who make the parts. Have you figured out exactly how it happened? Did an engineer specify the wrong part? Or was it an error in the layout where someone didn't understand the names of the footprints in their system?

If you can't get the SMT parts to solder properly, you might try using small wires to connect the parts.