Parts values on schematic question

But that's on account of the hidebound prejudice of the coder. ;)

Our in-house database/EDA system works fine with both.

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

This also avoids the problem what is a decimal separator The point is used as decimal separator mainly in UK and her (ex)colonies. Comma is used in most of the rest of the world. In some areas even a middle dot or apostrophe has been used as decimal separator.

On Friday, February 15, 2019 at 12:46:16 AM UTC-5, snipped-for-privacy@downunder.com w rote:

First time I saw a comma used for the decimal "point" the period was also u sed for the three digit separator. There are pathological variations that will produce a perfectly valid but completely different number in both syst ems. It's a good idea to avoid the decimal point when you can easily. Thi s is one of them.

Rick C.

Neither the metric system or the Imperial system require you to write numerical component values in a way that makes them difficult to read, or requires you to rely on a small, hard-to-see and easily lost decimal point.

In Europe you can at least mark the decimal point with a comma, rather than a the less extensive period.

Noe of the place where I worked were stupid enough to insist on using printed page orthography on text that was going to be silk-screen or blue-printed.

--
Bill Sloman, Sydney

Then you need better software.

You'd have to write a special parsing sub-routine to translate those strings into strings it would like. It doesn't sound as if it would be difficult, unless the person writing the program was remarkably inflexible and unimaginative.

--
Bill Sloman, Sydney

Get better software!

So if you received a document (schematic or otherwise) with 1.000 (ohms), what would you assume was the value? And what did the originator mean?

Alternatively, should software bend to fit people and cultures, or should people and cultures bend to fit one particular bit of software?

On a sunny day (Thu, 14 Feb 2019 18:19:53 -0800) it happened John Larkin wrote in :

No you do not use software that reads values from schematics. It is easy to write code that writes 2M2 for 2.200.000 Ohm in European notation for example.

2k2 3k3 all perfectly understandable, A lot better than the 0.01uF I often see in US circuit diagrams 10n The symbol says what it is (Farad, Henry or Ohm).

Do not confuse people who do it the right way.

On a sunny day (Thu, 14 Feb 2019 17:26:15 -0600) it happened John S wrote in :

I write 12 Ohm as 12R

/An/ imperial system. You could increase your car's MPG by 20% simply by buying your petrol in England.

Cheers

--
Clive

10? is 10 or 10R 510? is 510 or 510R (it also gets written as 511 with another conventi on) 1k? is 1k 1M? is 1M

If you add extra zeroes it implies extra precision, it's mostly not done.

4k7 type notation is primarily useful when info is being printed on paper, as it avoids dot deterioration causing errors. Naturally paper data is less common now, but still in widespread use. It's not a new system. We use the method on printed paper that is liable to degrade in use. It's much more o f an issue in the developing world.

NT

Another source of confusion is resistor markings. At a very large and well known American manufacturer the standard parts database contains a 601 ohm resistor. The tolerance is 1% or 5% (I forget which). This resistor is used in places where everyone else would have chosen

600 ohms (or the nearest standard value). New designs used this value because it was the closest to 600 ohms in the database. Nobody knew why this value was there. The resistor manufacturers were happy to make them in vast numbers. I suspect that a long time ago somebody copied the markings on the body of a 600 ohm resistor and they made their way, undecoded, into the procurement system. Once there, nobody wanted to go through the hassle of fixing it.

John

Except when it isn't :>

510R can also be written as k51 or 0k51

Likewise 470k can be expressed as M47 or 0M47.

That convention keeps the value a fixed width / number of characters.

I first saw that M47 system on 1960s USSR gear - could be even older!

piglet

Clifford Heath wrote in news:W_p9E.1047$ snipped-for-privacy@fx25.iad:

I just love how some idiots declare the US as the only country to not use the metric system. It is a lie.

The US, starting with the military and also auto makers, have been using the metric system since the '60s.

It all comes down to the individual idiosynchratic behaviors of individual companies and their owners.

And most folks observing it all apparently wear horse blinders every now and then.

OK, I'll take my Prius Prime Plugin and head there pronto.

--
 Thanks, 
    - Win

snipped-for-privacy@ieee.org wrote in news: snipped-for-privacy@googlegroups.com:

Resistor values are marked on the schematic. The method the UK uses is to place the multiplier alpha letter where the decimal point would go. It works as it negates the need or use of the ohm symbol and the decimal. It does not matter though as schematics are printed representations.

The parts themselves do not get marked in the same way, particularly space limited parts like SMD.

PCBs do not typically get values marked onto them either.

snipped-for-privacy@ieee.org wrote in news:a68175b1-61ac-4bf0-9141- snipped-for-privacy@googlegroups.com:

He is wrong about the evaluators. Reading his crap throws an error.

Tom Gardner wrote in news:hIu9E.1348926$ snipped-for-privacy@fx36.am:

The software should follow previous established standards, not attempt to steer or create a non standard modus operandi.

Standards are NOT 'culture'.

1m0 would be 1 milliohm. The difference between upper and lower case M is 10^9.

My convention is always at least 2 significant digits, no leading zeros.

10 Ohm will be 10R. 510 Ohm is 510R, 1k is 1k0.

--
Reinhardt