Ian and the group,

Although possibly redundant, long ago and far away, there was a Printed
Circuit Board.

According to the prehistoric legend of one galaxy, it got that name
because the conductors were made with a conductive ink which was
literately "Printed" on to a piece of nonconductive phenolic or
fiberglass support material which resulted in a "Board" with "Circuits"
to which components could be attached.

According to yet another prehistoric legend of yet another galaxy, it
got that name because the an ink was literately "printed" on to a thin
sheet of copper which was laminated to a piece of nonconductive phenolic
or fiberglass support material which was then etched in acid leaving a
"Board" with copper "circuits" on the nonconductive support material to
which components could be attached.

Who knows for sure which, if not both, are true.

Anyway, in this galaxy, and in this country (U.S.), that item was called
a "Printed Circuit Board", or PCB, which was originally recognized by
all by that term, and that PCB was a component part on a parts list with
other parts, all of which went together to form an "Assembly".

This "Assembly" was variously given a name such as XYZ, and would be
called variously the "XYZ", the "XYZ Assembly", the "XYZ Printed Circuit
Board Assembly" (PCBA), or the term which was originally used more
commonly, and specific in the title of a drawing, was "XYZ Printed
Circuit Assembly" (PCA), or more correctly, "Printed Circuit Assembly,
XYZ".

Thus we had PCB for the bare board, and PCA which was used by most (but
certainly not universally for the assembly). Some even then and to this
day call the finished Assembly a "Printed Circuit Board".

Enter the Military, and since they liked to define everything their way,
what the industry had universally called a "Printed Circuit Board" or
PCB, the Military called a "Printed Wiring Board" or PWB, which meant
that if you made a PCB for a Military Contract, it was no longer a PCB
but now the identical item was to be referred to as a PWB.

What was called the "Assembly" by some, or variously, the "Printed
Circuit Board Assembly" (PCBA), or "Printed Circuit Assembly" (PCA), was
what the Military in all cases called the "Printed Wiring Assembly" PWA.

Hence by the 70's we had bare board which the Military called a PWB and
Industry called a PCB, but which were otherwise identical, and a board
with its components installed which the Military called a PWA and
Industry called a PCA (for the most part, but not universally), which
once again were otherwise Identical.

Thus, with very few exceptions, a bare board is a PCB in industry and a
PWB to the Military. In recent years this has also come to be called a
"Circuit Card" (CC), or simply "board" or "card".

Again, with few (but more) exceptions, a assembled board is a PCA in
industry and a PWA to the Military. In recent years this has also come
to be called a "Circuit Card Assembly" (CCA), or again simply "Board",
or "Board Assembly",or "Card", or "Card Assembly".

According to some current definitions, some are now trying to limit the
usage of "printed circuit" to somehow include "printed component", such
as in printing resistors on a board or substrate with resistive ink. We
here need to recognize that over the years definitions tend to evolve,
and what eas a PCB or PWB in the past is now being redefined.

The fact is, from the Perspective of RF, we have been making components
(inductors, resistors, capacitors, RF chokes, etc. (not to mention
controlled impedance transmission lines in the form of Strip Line and
Micro Strip)) for years on PC Boards out of copper, and only recently
have the EDA companies began to take notice. (Go ahead, ask Protel what
an RF Choke is, and how to make one in Protel).

Hopefully of some help,

JaMi Smith


-----Original Message-----
From: Ian Wilson [mailto:[EMAIL PROTECTED]] 
Sent: Tuesday, February 19, 2002 8:48 PM
To: [EMAIL PROTECTED]
Subject: [PEDA] What does "printed circuit board" mean to you?

G'Day all,

I was having an email discussion the recently...

We use the term printed circuit board (or PCB) to describe the bare
board 
(no components fitted) and the term printed wiring assembly (PWA) for
the 
assembly (PCB + components).  Some of the younger colleagues around here

are comfortable with PCB and "assembled PCB" as meaing the board and the

board+components respectively.

(One of the older school here use the term PWB (printed wiring board) 
interchangeably with PCB.  And PCA (printed wiring assembly) 
interchangeably with PWA.  No guessing which industry he came from...)

How do others interpret the following terms?
PCB (printed circuit board)
PWA (printed wiring assembly)

What term(s) do you use for the assembled PCB?

Hooroo,
Ian Wilson

(Maybe the Topic Police will get cranky over this flagrant mis-use of 
electrons but we can move to the OT list if it gets out of hand.)


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