Schematics & standards

Am 18.06.2010 22:18, schrieb David Nebenzahl:

I prefer the traditional (German?) rectangle shape for resistors, your zigzag things too much look like inductors, Herr Nebenzahl ;-)

Same here.

I prefer the nKm to n.mK, as in the second case the very small "." makes the difference between 5.6 and 56.

Falk

I agree mit Herr Nebenzahl.

I grew up with Popular Electronics, and it and its sister magazine, Electronics World, had the nicest-looking schematics I've ever seen, anywhere. Obviously that's a matter of taste, but they were clean and handsome (to me).

On 6/18/2010 1:32 PM Falk Willberg spake thus:

Danke schoen, Herr Falk. (ich bin nein ein Deutschlander)

So those little boxes are a German thing, eh?

Well, you should see my on resistor symbols (zigzags). You'd *never* mistake one of them for an inductor.

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

How often have you come across compressed pdf-type schema or reduced paper-based ones where the decimal point has disappeared , and there is no kerning for dots, so you cannot infer a position for any dot position. Replace R/K/M for the dot makes a lot of sense.

Yes, I'd go along with that. It is a far more sensible way of showing values, and I can't see anything counter intuitive about understanding it. I still prefer zig-zags for resistors, and if I'm drawing a quick 'sketch' of a diagram, I always still 'jump' the non-connected lines. However, when I'm hand-drawing a diagram properly, with nice straight lines and 'gridded' components, I always break one of the two crossing lines, where they break, so sort of the 'jumping over' convention, but without the actual bridge being drawn. I'm not sure where I first saw this, but schematics drawn like it, look quite nice. There's no question about whether lines do connect or not, and the brain fills in the little missing bit of the line without you having to think about it. Where lines do connect, they get a nice dot on them.

I always still use the original logic symbols for gates and counters and latches and inverters and so on. I find the new style 'blocky' symbols need too much looking at, and taking into consideration of additional writing and symbols within the block. I always thought that the original symbols were all sufficiently different for the most part, to allow instant understanding of function by quick glance alone.

I would agree that appliance schematics are often unclear, and use odd symbols. Also, with apologies to Herr Willberg, I think that German schematics from 20 or 30 years back, are some of the worst to follow that I've ever seen. I defy anyone who's not German, to follow a Grundig schematic, for instance ...

Although Dutch, some of Philips' ones from a few years back were also a nightmare to follow. They had a very frustrating convention regarding where signals went when they (frequently) disappeared off the side of a page, and the signal was often nigh on impossible to ever find again ...

But the prize for impossible to follow schematics, has to go to the automotive industry. Those diagrams have a convention all of their own, and always have done. Some of the most frustrating fault-tracing sessions of my life, have involved cars and the electrical diagrams for them. They are a cross between a schematic and a wiring diagram, with symbols peculiar to and only understood by automotive manufacturing initiates. Every bullet and connector is shown, using a variety of different conventions between manufacturers. Schematics go across multiple pages, with wires that leave often almost impossible to re-find on the next diagram. Colours, wire gauges and goodness only knows what other info, are all crammed onto the diagrams. Nightmare ...

Arfa

Using a rectangle for a resistor allows the value to be inserted in it - quite useful where they're close. And therefore 4K7 takes up less room than 4.7K - and a full stop is more easily missed when reading. Similarly a circle for an electrolytic, oval for non electrolytic. After all, an IC is just a box - not a representative of what it does.

As regards a dot where two cables join, I agree. For some reason this isn't used much these days. With usually a gap where two circuits cross rather than a loop. With a dot you don't have to do either.

--
*I used to have an open mind but my brains kept falling out *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

I

of

I'm

break,

like

need

and

understanding

where

and

and

my

and

gauges

diagrams.

My beef is with caps marked 270 say, is it 27 or 270 ?, if there are no other same series caps on the board for convention comparison, eg 471

"Falk Willberg"

** Little boxes, little boxes and they're all made out of ticky tacky .....

Must be some kind of rabid Nazi obsession to put everything and everyone into boxes ???

With or without Zyklon B gas for filler.

** Lotsa folk fail to see the * point * of this ..... ** Must be one of them WW2 Messerschmitt pilots

.... Phil

You should see some old IBM mainframe schmatics. Almost everything is a box.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

[...]

Some years ago I owned a Standard Vanguard and the circuit diagram in the owners handbook (you didn't need to buy an expensive workshop manual) was exemplary. I have never seen one as clear as that for any other car.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[...]

I find the 'gap' convention is easy to draw (with a computer) and extremely easy to read. It also looks tidy. Four-way junctions which could be mistaken for crossings should never be used, they should be staggered instead.

e.g.

I first saw it in German and Dutch publications. Once you have become accustomed to it, it is quite easy to use and it is utterly unambiguous, even when badly photocopied.

Probably the best circuit diagrams were those in Wireless World when it was still part of Illiffe Publications (also those in BBC Technical Instructions). They were drawn by trained draughtsmen who also understood electronics.

The worst ones are those with boxes. A symbol should indicate what the component is without having to read the small print. I was very pleased when Wireless World declared that it would not be following British Standards and would continue to use 'proper' symbvols.

--
~ Adrian Tuddenham ~
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www.poppyrecords.co.uk

Am 19.06.2010 15:59, schrieb Phil Allison:

...

By the way, when you have stopped to slaughter aborigines? Before or after WWII?

Falk

On 6/19/2010 8:35 AM Adrian Tuddenham spake thus:

BZZZZZZT! Fail.

While the gap thing looks OK for non-crossing wires, I have to ding the drafts-person of that schematic for the following:

o Idiosyncratic symbols for electrolytic cazapitors[1] o Idiosyncratic ground symbol (one horizontal line????) o And no, I disagree about those offsets for connecting wires.

That's totally unnecessary here: it would be quite obvious that all those vertical wires connect to what is obviously a bus or rail. A well-drawn dot is all that's needed there.

(And I don't much like their transistor symbols either)

[1] With apologies to J. Liebermann.

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

It appears that you had no difficulty identifying them, so they succeeded as symbols. The polarity is also a lot more 'intuitive' than the conventional symbol.

Again, you recognised it without ambiguity and it isn't all that unusual:

That's your preference, but I prefer offsets because they are utterly unambiguous, even in a poorly copied drawing.

For junction transistors they are incorrect, I agree, but I have become used to them. I find it takes me a while to get my mind around the correct symbols because they are so rarely used nowadays

Just for fun, I've replaced the point-contact symbols in that drawing with the correct junction ones:

The wrong symbols have become so well-estabilshed nowadays that I doubt if most people even noticed they were wrong.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On 6/19/2010 1:19 PM Adrian Tuddenham spake thus:

Now that's just plain *weird*.

Since when are the *conventional* symbols for (junction) transistors considered to be for the old, obsolete point-contact ones? Every single schematic that uses transistors--modern silicon ones, not ancient point-contact germanium ones--uses the conventional symbols, like the ones in the first drawing you posted.

I've *never* seen symbols like the ones in your "new, improved" drawing. Those are just plain idiosyncratic, non-standard and weird. They look kind of like diodes with an elongated anode.

I'll stick with the tried and true standard symbols, thank you very much.

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

I thought you would find them interesting.

When junction transistors were first introduced there was a need for a new symbol to distinguish them from the point-contact type which the 'conventional' symbol represented. Several eminent journals and text books changed over to the new 'junction' symbol, but, by then, the point-contact symbol was so well established that the change never caught on.

You will find the 'junction' symbols in some Acoustical Quad circuit diagrams, Peter Walker was a stickler for getting things right. They also appeared in Wireless World for a while and are used in "The Foundations of Wireless" by M.G. Scroggie (8th Edition) specifically to distinguish the two different types of transistor.

They certainly look strange when you have been used to the point-contact symbol, but you must admit they give a clear representation of a junction transistor.

At least you will be able to recognise the other types if you ever encounter them again.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

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

Crossings (four-way intersections) never connect. Three-way intersections always connect. Stick with that convention and neither the humpie or a dot are needed, although dots do "look right."

There is an authorized reprint of H&H's "How to Draw Schematic Diagrams" from AoE Appx E over at

--
Rich Webb     Norfolk, VA

I must say that I don't really like the staggered connections, but what's wrong with the transistor symbols ? And the single heavy horizontal line for the 0v rail, is very common this side of the pond. 0v rails always used to be shown as a heavy horizontal line right across the schematic, sometimes with a chassis symbol attached as well. These days, most schematics are so complex, that the 0v line is now left out, and 'abbreviated' to individual short heavy lines at each connection point on the schematic. The electrolytic symbol is not, however, the one commonly used here, which is a pair of rectangles, one filled in for the -ve side, and the other open for the +ve side. Sometimes, the American convention of one straight and one curved plate, is used.

Arfa