On Sat, 06 Dec 2008 17:30:05 +0000, Eeyore
wrote:



John Fields wrote:

Eeyore wrote:
gore wrote:

I work at an electronics contract manufacturimg facility. We do work for
several companies and I wonder why they use different labels on the
schematics and pcb's to refer to IC's. Some of them have a U1, an A1, and
X1, or an IC1. Why do they do this? Is there a standard used to label IC's
in a schematic? Just curious why this is.

X should be a crystal.

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No, a crystal is designated with a 'Y'.

What you're probably thinking about is the abbreviation for 'crystal',
'XTAL'.

You won't see any Y crystals in Europe IME.

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You will on stuff that we send there.
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A would be an amplifier (I haven't ever seen that btw)

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Then how would you know?

Anyway, it's not for 'amplifier, it's for 'assembly'.

Which is hardly a pcb component is it ?

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It is if it's a subassembly, which is when the 'A' reference designation
is used.
---

IC is self-explanatory and is widely used in Europe
U is some weird US practice. U for what ?
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Unit.

Terrell disagrees. I have now heard explanations of Unknown, Unique and Unit !

IC otoh is 100% unambiguous.

'unknown' and 'unique' are nonsensical. 'U' is not, and when seen on a
schematic unambiguously identifies the part.

Besides, since the integrated circuit was invented in the US, no doubt
the 'U' reference designator was too.

That, in and of itself, was probably enough to send you lot into a tizzy
and cause you to spend a lot of sleepless nights trying to come up with
something other than the NIH 'U'.

Typical.

JF