Difference btw PWB and PCB

They're the same thing.

Harry C.

As far as I can tell, if you've worked at TI you call it a PWB. Everyone else calls it a PCB.

Blake

Depends on whom you ask. There is no industry-wide standard.

I call a finished subassembly a PCB and a bare, unstuffed board a PWB.

Not quite. At one time, printed circuit boards quite commonly used screen-printed-on components in addition to wiring, whilst printed wiring boards were just that - wiring.

I remember Philco radios with printed resistors.

The practice has now fallen into disuse, apart from circuits fired onto a ceramic substrate, and etched coils, so the two terms have become synonymous.

I wonder if anyone here remembers (or has heard of) the "Tinkertoy" ceramic printed circuit assemblies of the 1940s?

I have some stereos from the 1980s (quite possibly made in the same plant), that have traces and resistors screened onto the component side of the board. I

On Mon, 11 Aug 2003 22:50:13 +0800, "Alex C" Gave us:

They are one and the same. PWB is the old, archaic term, and PCB is the new current usage.

On Mon, 11 Aug 2003 18:06:30 GMT, Blake Gave us:

There are several monikers. PWB PCB PWA CCA UUT, etc.

Printed Wiring Board.

Printed Circuit Board

Printed Wiring Assembly

Circuit Card Assembly

Unit Under Test. (a stretch)

On 11 Aug 2003 13:13:02 -0700, jeffm snipped-for-privacy@email.com (JeffM) Gave us:

Sure there is. It is more about era than standards.

When they were first introduced, they were referred to as Printed Wiring Assemblies, Or Printed Wiring Board(s). Once Printed Circuit Board came into vogue, the other is used primarily by old foggeys that are still entrenched in the past, or just to familiar with it to change, but these days, PCB is pretty much the accepted norm.

Actually the "assembly" terms apply to the loaded boards, where the PCB/PWB apply only to the bare board.

Blake

On Tue, 12 Aug 2003 04:04:30 GMT, Blake Gave us:

Actually, contract manufacturers refer to assemblies as PCBs. Only those of us that actually do the developments of products make the distinctions you outline, and know the difference.

All of the acronyms that have an "A" in them are obviously about loaded assemblies. Since they have military roots, it is unlikely that you will hear today's commercial contract houses using any of them. They jus' call 'em PCBs. Loaded or not. There has been a BIG relaxation in the industry. When I was learning it, ALL personnel on the lab floor had electronic training. Now we gotz idiot on the line that can't even read assembly drawing OR speak in the language of the country they are living and working in. Pretty sad, that.

That's pretty late. I was thinking back to the '50's and '60s.

Do that a lot these days. Sad isn't it?

On Tue, 12 Aug 2003 22:30:12 +0100, Fred Abse Gave us:

Hell, back then, most of them were point to point wired! Hahahahahah...

Read the latest magazines from IEEE, this is coming back because of a need to reduce board size. Brad PC Logic

Schematic entry and PCB design software

On 13 Aug 2003 07:27:13 GMT, snipped-for-privacy@aol.com (AtPCLogic) Gave us:

Have you ever even seen an 0402 resistor? What about 0201? They are both in use... Today. ANY film screen process could not possibly control the value with repeatable enough results for it to be economical to do at those sizes, on the fly. Thousands of resistors get trimmed at one time on a chip manufacturing line, once the average slicing point is determined, then they get culled again after glazing for the one percent units Probing and laser trimming on a custom PCB AIN'T cheap. I doubt that you'll be beating the 0402 or 0201 form factors any time soon. Both for automated assembly reasons, AND precision.

So... what exactly is "coming back"?

On Wed, 13 Aug 2003 10:56:43 +0200, Jean-Michel Friedt Gave us:

Still a ways off as far as a low cost, high volume, quick turn manufacturing process, however.

Pretty funny, I read my reply later and thought that the "actually" sounded pretty authoritative, and I was only guessing. Oh well. The hazards of being a know-it-all.

Blake