Parts values on schematic question

snipped-for-privacy@gmail.com wrote in news:3faa63ee-ae35-499b-9020- snipped-for-privacy@googlegroups.com:

I agree.

I was at a gov contract mfgr. We were not mil spec as no one is any more. However, IF a particular procurement contractor wanted a certcain circuit built with 63/37 solders, we might eve have to get chips re-balled for them. The contractor specifies.

And they can also complain about schematic nomenclature, which is all this is about.

A good engineer knows about naming conventions and even how to investigate and learn about any encountered during any normal day. Thereafter having knowledge of yet one more standard in the recent memory zone of his brain.

Einstein said that we should not commit to memory anything that can be looked up as it clutters the mind. He was right.

But here is how inductors go.

The part marking uses an R for the decimal signifier.

A schematic, however, should never use a coded reference. We have high resolution laser printers now, so things like decimal points

are three orders of magnitude each. We are familiar with that.

Trying to garner some other country's normal usage should not be something I need to do. "4R7" is LAME when the printer AND the reader can clearly see the decimal point.

Why some dopes decided that using a comma as some kind of decimal signifier because of some lame calligraphic hack fix method for far sighted elders did has really f***ed things up. A decimal point is the same as a period... PERIOD! Keep that dumb shit in your accounting circles, but leave it out of math and engineering! Yer screwin' up the whole world.

Reply to
DecadentLinuxUserNumeroUno
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So you're not sure about the value to three or 12 orders of magnitude?

10u is 10 microfarads to us.

10 would be 10 farads, namely a supercap.

That convention, among other virtues, keeps scientists from mocking us as rubes.

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

Of course, and any industry has its non-SI-standrd practices & sometimes units. That's life, and there are reasons for each & every one of them. If you work in a given industry you need to know what's used & done in that industry.

NT

Reply to
tabbypurr

kin

sonal taste. There are multiple standards for various things, and in many c ases no-one to enforce them, so it's inevitable that many are seen in pract ice. It's a complete non-problem.

Vcc and Vee was the only correct way. I never saw much sense in either that convention nor the insistence that it was somehow the only correct one and must be used.

ly always means uF, sometimes pF, only seldom farads.

that's an odd thing to say. Could you not tell which convention were in use by looking at the circuit?

that really has nothing to do with it.

NT

Reply to
tabbypurr

I haven't noticed you caring much about People Who Know Best. ;)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

R for radix, not ohms.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

That might be 4.7 nH on our boards.

We actually stock a 4.7n inductor. 1.6n, too.

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

So, wouldn't that be 4n7? Or 1n6?

Reply to
John S

This was written by scientists:

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It's heavy going in places (I skip those parts) but some of it is stunning revelation. They talk about engineers a lot - so as to not mention God directly - and seem to like us.

"Scientists are constantly lashed with the strop from Occam's razor... if one design is simple and another complicated, choose the complicated." (with references)

They also advise to not use one part to do two jobs. I figured that one out decades ago.

--
John Larkin         Highland Technology, Inc 

lunatic fringe electronics
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Reply to
John Larkin

(Shrug) It wouldn't be a problem if some bozos somewhere hadn't arbitrarily decided to start using commas instead of periods as decimal separators. Change for the sake of change, yay.

Inventing yet another way to write numbers is, indeed, stupid, and is also a good way to hatch massive engineering disasters. I don't know if I'd call it 'amateur', though, since the hams still use conventional notation. :-P

-- john, KE5FX

Reply to
John Miles, KE5FX

But not in Europe and most of the rest of the world, where they adopted a different convention.

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Except that the USA and the UK are the only one's that went for the particularly dumb calligraphic hack of using a period rather than a comma as the radix character.

Clearly a mistake.

--
Bill Sloman, Sydney
Reply to
bill.sloman

That is simply not the case. Look at the history of the decimal point.

-- john, KE5FX

Reply to
John Miles, KE5FX

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Only the US and the UK seem to have decided to use periods as decimal separators.

Simon Stevin - a Dutchman - was the first to use decimal fractions in Northern Europe but he didn't use either the comma or the period as his radix character.

Stevin's notation was bit bulky.

Inventing decimal fractions was probably a good idea. Why England chose a different decimal radix character from the rest of the world is not clear to me, but it was probably a bad decision.

--
Bill Sloman, Sydney
Reply to
bill.sloman

I did, and have posted at least one link to it. You clearly haven't.

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Bill Sloman, Sydney
Reply to
bill.sloman

different convention.

ath and engineering! Yer screwin' up the whole world.

cularly dumb calligraphic hack of using a period rather than a comma as the radix character.

On your part maybe?

"The countries found to the north, like the U.S.A and Canada, use the decim al point, although the comma is used in the Francophone area of Canada as w ell. Countries closer to Central America, such as Mexico and the Caribbean Islands, also use the decimal point."

"Australia, New Zealand, as well as the islands and archipelagos close to t hem, use the same system as the rest of the Anglophone countries. Therefore , the decimal separator they use is a point."

"There is no official standard used across Africa, but we know that some co untries like Zimbabwe, South Africa, and Cameroon use the decimal comma. Ot hers such as Botswana, Kenya, and Nigeria, use decimal points."

"The decimal point is generally used in countries such as China, Japan, Mal aysia, Singapore, Sri Lanka, The Philippines, etc."

Wow! That's a lot of wrong!

Rick C.

Reply to
gnuarm.deletethisbit

So you are the only person here who can't use Google properly?

Rick C.

Reply to
gnuarm.deletethisbit

Trailing zeros before a multiplier (or none) are theoretically ambiguous as to whether or not they are significant digits. Of course, if you know it i s E24, then you _usually_ know two SD, and if unique to E96 or E192, then y ou know 3 SD. (For example, 590R is E96 (or E192), but not E24, thus the tr ailing zero counts.)

Also, they are making low tolerance resistors matching the "old" E24 values . One can't be sure if it is the usual 2 SD for E24 w/o other info. If the tolerance is listed in the schematic, then it is a dead giveaway, of course . If not, the ambiguity may exist.

So, for example, w/o some other SD key to "200R" one does not know if it is 2 or 3 SD. k20 and k200 (0k20 and 0k200) are distinguished for SD w/o addi tional info, yet they are quite ugly.

This isn't much of a problem in practice, of course. I usually have toleran ce "turned" on in a schematic if it is important. The tolerance (and ppm) i s better than the SD anyway.

Reply to
Simon S Aysdie

That would be 4.7 henrys, then.

Reply to
krw

I use bunches of them. It's a good number for switching power supplies (they generally run between 1uH and 10uH, depending).

Reply to
krw

If you could use Google properly, you could prove it by posting your own links.

You haven't. Pity about that.

--
Bill Sloman, Sydney
Reply to
bill.sloman

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