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Difference btw PWB and PCB

Discussion in 'Misc Electronics' started by Alex C, Aug 11, 2003.

  1. Alex C

    Alex C Guest

    Hi,

    Can anyone kind to tell me what's the difference btw PWB (printed Wiring
    Board) and PCB (printed Circuit board)?
    I can't find it in the net.... I heard some refer to PCB others said about
    PWB, but any difference(s)

    Thanks
     
  2. They're the same thing.

    Harry C.
     
  3. Blake

    Blake Guest


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

    Blake
     
  4. JeffM

    JeffM Guest

    what's the difference btw PWB (printed Wiring Board)
    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.
     
  5. Fred Abse

    Fred Abse Guest

    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?
     
  6. Gary Tait

    Gary Tait Guest

    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
     
  7. DarkMatter

    DarkMatter Guest


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

    DarkMatter Guest

    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)
     
  9. DarkMatter

    DarkMatter Guest


    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 <sp>
    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.
     
  10. Blake

    Blake Guest

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

    Blake
     
  11. DarkMatter

    DarkMatter Guest


    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.
     
  12. Fred Abse

    Fred Abse Guest

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

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

    DarkMatter Guest


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

    DarkMatter Guest

    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"?
     
  15. DarkMatter

    DarkMatter Guest


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

    Blake Guest

    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
     
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