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naming schemes for components on PCBs?

S

Steve Kavanagh

Jan 1, 1970
0
M. Noone said:
Is there a standard way to name components?

I believe I remember an IEEE standard on reference designations. I am
afraid I don't recall the number at present. If I remember correctly
it does not address schemes for meaningful designations within a board,
but it would discourage the use of "CA1, CA2" etc.

73,
Steve
 
P

Pooh Bear

Jan 1, 1970
0
John said:
ACK! And besides, the available space for reference designators is
getting very tight these days.

You're suggesting that D takes up *more* space than CR ?

Graham
 
R

Richard Henry

Jan 1, 1970
0
John Larkin said:
ACK! And besides, the available space for reference designators is
getting very tight these days.

Or for part numbers ( or any meaningful identification) on the parts.
 
R

Rich Grise

Jan 1, 1970
0
Hi - I am finishing up the layout of my first really sophisticated PCB.
(over 12 ICs, 3 modules, over 10 connectors, and nearing 100 discretes,
among other components).

When laying it out I've just turned off all the value and name layers.
The names of all the parts are just incremental in the order in which I
added them (C1, C2, etc.)

But this seems a very ugly naming system. I have two ideas for ways to
fix it:

1. there are maybe 8 or so different types of capacitors on this board
- I thought that I could give the types different letters (ie A, B,
etc.) and then name all the capacitors of type A CA1, CA2, etc. Then
all of type B CB1, CB2, and so on and so forth.

2. Instead of giving them different type names, I could just name all
those in type A in a series (is C1-C10 are type A, C11-115 are type B,
and so on)

Is there a standard way to name components? Having a naming scheme is
especially important as this is a prototype board and will thus be
soldered by hand.

Historically, I've named them in the order they appear on the schematic.

In real life, however, I've found that they take the layout and just
number them left to right, top to bottom, the way you'd read letters on
the page.

What you suggest, using different designators based on "type" of capacitor,
is a non-starter. Don't bother, it will just confuse things.

You could silk-screen values onto the board, but don't do "CA1, CB1, CA2,"
and so on - it's "C1 .1 uF" "C2 10 uF 16V" stuff like that.

The order doesn't matter as long as you're consistent and your parts list
matches.

Good Luck!
Rich
 
R

Rich Grise

Jan 1, 1970
0
Where the hell did CR come from anyway ?

"Contact Rectifier", I've heard.
Not to mention U or Q !

They came up with Q because T was already taken, and then U because
it was the only letter left.
We use D, IC and TR. As do most Europeans.

Hope This Helps!
Rich
 
J

JeffM

Jan 1, 1970
0
Where the hell did CR come from anyway ?
"Contact Rectifier", I've heard.
Rich Grise
I've heard it like DJ said: "Crystal Rectifier".
..
..As good an explanation as I've heard.
..
..A = repairable assembly
U = unrepairable assembly (e.g., throw-away modules)
 
R

Robert Latest

Jan 1, 1970
0
Exactly how I do it. It's something I picked up from a service manual for some
gear twenty-odd years back.

....back when service (and even user) manuals came with
schematics. Many of those schematics were real beauties. with all
their waveform annotations and stuff. Even consumer HiFi stuff
came with full-blown schematics, which made fixing it a breeze.

robert
 
R

Rich Grise, but drunk

Jan 1, 1970
0
I've heard it like DJ said: "Crystal Rectifier".
.

OK, that's two to one. Crystal it is! ;-D
A = repairable assembly
U = unrepairable assembly (e.g., throw-away modules)

As good an explanation as I have heard! :)

Cheers!
Rich
 
W

Walter Harley

Jan 1, 1970
0
Richard Henry said:
However, the effect will be negligible because I have been transferred to
the firmware group and I am no longer allowed to do hardware designs.

You can do it with line numbers, then. ;-)
 
Rich said:
Historically, I've named them in the order they appear on the schematic.

In real life, however, I've found that they take the layout and just
number them left to right, top to bottom, the way you'd read letters on
the page.

What you suggest, using different designators based on "type" of capacitor,
is a non-starter. Don't bother, it will just confuse things.

You could silk-screen values onto the board, but don't do "CA1, CB1, CA2,"
and so on - it's "C1 .1 uF" "C2 10 uF 16V" stuff like that.

The order doesn't matter as long as you're consistent and your parts list
matches.

Good Luck!
Rich


The simple convenient option is to put the usual C12 etc on, then add
values and types as and where theres room. Thus some parts are fully
described on the board, some arent. With some boards, few will be, with
some many will. Just a case of making the most of the space.

And why oh why do so many PCBs still have big blank etched areas?? Dont
someone know its cheaper to not etch those bits?


NT
 
Rich said:
Historically, I've named them in the order they appear on the schematic.

In real life, however, I've found that they take the layout and just
number them left to right, top to bottom, the way you'd read letters on
the page.

What you suggest, using different designators based on "type" of capacitor,
is a non-starter. Don't bother, it will just confuse things.

You could silk-screen values onto the board, but don't do "CA1, CB1, CA2,"
and so on - it's "C1 .1 uF" "C2 10 uF 16V" stuff like that.

The order doesn't matter as long as you're consistent and your parts list
matches.

Good Luck!
Rich


The simple convenient option is to put the usual C12 etc on, then add
values and types as and where theres room. Thus some parts are fully
described on the board, some arent. With some boards, few will be, with
some many will. Just a case of making the most of the space.

And why oh why do so many PCBs still have big blank etched areas?? Dont
someone know its cheaper to not etch those bits?


NT
 
J

Joel Kolstad

Jan 1, 1970
0
Rich Grise wrote:
And why oh why do so many PCBs still have big blank etched areas?? Dont
someone know its cheaper to not etch those bits?

Depends on the quantity... many PCB shops aren't interested in going through
the process of figuring out what sort of discount your board deserves due to
your not etching all the blank spots unless you're talking quantities of
10,000+...
 
Z

Zak

Jan 1, 1970
0
And why oh why do so many PCBs still have big blank etched areas?? Dont
someone know its cheaper to not etch those bits?

ISTR some boards are produced in reverse: a very thin layer of copper is
etched, then more copper is electroplated.

Electroplating is done for through-hole anyways.


Thomas
 
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