naming schemes for components on PCBs?

Sometimes I have to provide a board to match the schematic of an existing product for which spare boards are NLA. At that moment, the non-backannotating system I use isn't a concern.

Then again (somewhat O/T), I don't autoroute either ;-)

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

"Contact Rectifier", I've heard.

They came up with Q because T was already taken, and then U because it was the only letter left.

Hope This Helps! Rich

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)

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

Graham

...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

OK, that's two to one. Crystal it is! ;-D

As good an explanation as I have heard! :-)

Cheers! Rich

You can do it with line numbers, then. ;-)

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

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

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

As opposed to a vacuum rectifier. The 1n21a, b, etc. were used by radars in WWII.

The symbols are specified in:

ANSI Y32.2 CSA Z99 IEEE 315

probably superceded by EIA specs now.

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