On Fri, 18 Jun 2010 13:18:41 -0700, David Nebenzahl
wrote:

Someone else made a comment in another thread here about weird
schematics (like for home appliances).

Wanted to get a small discussion going on that topic. My take: there are
good and bad standards for schematics. Personally, I can't stand the
ones that use rectangle shapes for resistors, instead of the traditional
zigzag that [insert name of deity here] intended to be used. (And even
here there are lots of variations, like old-fashioned schematics that
took this symbol rather literally and sometimes had ten or twelve zigs
and zags, as if an actual resistor was being constructed on paper).

Likewise the wire-connecting/jumping convention: here I much prefer the
modern approach, which is to use a dot for a connection and no dot for
no connection, rather than the clumsy "loop" to indicate one wire
jumping over another with no connection.

Regarding resistor values: Who the hell came up with that new way of
specifying resistance values, like "10R" "or 5K6" or whatever? And why
use this system? I've always used the plain value of the resistance: 10,
56, 5.6K, 56K, etc. Simple, obvious, requires no interpretation. Is this
some kind of Euro thing?

In general, some schematics just look and feel nicer than others. A
well-drawn schematic is a pleasure to read. A bad one--lines too thin or
too thick, misshapen symbols, idiosyncratic interpretations, etc., just
don't look right.

Feel free to add your own schematic pet peeves here.
Well, the worst schematics of all are those which you cannot find.
Even the most miserable scratching on a crumpled piece of paper is
better.

While I learned using the 3.3K style, I fiend the 3K3 eminently
satisfactory, especially because of the redundancy. As was
mentioned,, this is important when dealing with a PDF of a poorly
scanned, poorly printed original.

I prefer the 'old' style - zig-zag lines for resistors, parallel lines
for non-polar capacitors, etc.

Lines should be drawn with the little loop when crossing lines do not
connect, a dot when they do. Again, redundancy.

Tags indicating the signal connecting to an IC should have an arrow
indicating if the signal is an input or an output, double arrows for a
bidirectional bus. And when a signal goes off the page, the
description should be accompanied by the page and grid location of the
destination, as in SYNC 3E5 indicating the SYNC signal is coming
from page 3, grid location E5.

As a bonus, the location of each component should be tabulated,
either on the schematic, or in a separate chart so it is possible to
determine that IC205 is on the bottom side of the circuit board at
grid location J12.

PlainBill