EEVblog #1129 - Creating a Nice Readable Schematic

[EEVblog]

How to turn a horrible unorganised schematic into a nice readable modular schematic with proper signal flow.
Tips on industry expected layout techniques.

Using the open source Haasoscope oscilloscope as an example.

Please do NOT complain about the length of this video. I know. It is what it is.

[Mr. Scram]

The video is so long!

I like it. In depth nuggets of knowledge that help me get from amateur hour to something slightly better is why I come to Eevblog.

[eV1Te]

I found a mistake: 0.01 uF is 10 nF, not 100 nF as you converted it to in the video at about 45:00.
It can also be written as 0u01, but not 0u1 nor 0n01 as you did.

I won't judge you because I have confused myself with notations like in the past as well.
Probably why you should stick to not using to many zeros after the decimal point in the first place. Hence your comments were spot on 

[Arznei]

So much OCD triggering in this video. It's a real shame the Eagle import didn't quite work (regarding the grid), still enjoyed it though!

I feel like the schematic could have really done with some multi-part symbols (I know you didn't want to mess around with them here), especially with the dual-OpAmps.
What are your opinions on splitting up big components like the FPGA though? I think while splitting it up does seem reasonable (and I've seen it done quite a lot) you don't really gain anything by doing so. You either put all the parts near each other (often on a dedicated sheet) or you plaster them around your schematic wherever they are needed. The latter might tidy up your wires and spare you some net labels but at the expense of the FPGA now beeing all over the place, which I find pretty confusing if you want to check what the FPGA is doing in the schematic.
What are the best practices here?

[Icchan]

This video is really sorely needed one. From now on, if I see horrible schematics I can refer to this one and be done with it. 

It would be really nice if you released the tidied schematic as a PDF AND as a source file. Even if it's Altium format, it would be a good gesture towards OSHW community regardless.

I believe you have a GitHub account?

Thanks for the video and length is warranted on this occasion. hmm... gave me an idea... maybe I could make a video that's a bit more structured and concise, with chapters and time stamps so that people in a hurry could learn the same ideas but with more scripted and overly edited^tm way?

[EEVblog]

It would be really nice if you released the tidied schematic as a PDF AND as a source file. Even if it's Altium format, it would be a good gesture towards OSHW community regardless.

I believe you have a GitHub account?

Sorry but no, it's too much work. The import screwed up a lot of things.
The designed did an update a few days ago I didn't know about, I was using an old eagle import from last week.

[Rutger]

The naming convention should be the number 1 tip. It was buried in the video at 1:12:00, and hard to find.
I think David should make a 5 min version of this video and go over the 10 things on do's and don'ts.

[firehopper]

or maybe just a top 10 things to do or not in a schematic?

[wilfred]

The naming convention should be the number 1 tip. It was buried in the video at 1:12:00, and hard to find.
I think David should make a 5 min version of this video and go over the 10 things on do's and don'ts.

Yep. 5min should mean it'll sneak in under 20. But I was thinking a condensed version would be really useful. More on what you should do only though.

[EEVblog]

or maybe just a top 10 things to do or not in a schematic?

Those Top 10 Youtube channels sure do get a lot of views...

[CJay]

or maybe just a top 10 things to do or not in a schematic?

Those Top 10 Youtube channels sure do get a lot of views...

It's not a bad idea, top ten tips on how to create a readable schematic, top ten tips on how to lay out a board, top ten blah blah...

Dunno how much work it'd be but it would be useful

[www2]

What are the opinions about putting the value/part number inside the part than outside?
Example: https://imgur.com/a/YfDt3Io

[woox2k]

Those Top 10 Youtube channels sure do get a lot of views...

I hate these things. Sure they give a lot of views since these are essentially just to trick our brain to feel like it learned something and release some chemicals that make us feel better. They are pretty much useless for learning something though. Our brains are not a simple databases capable of remembering random facts.
That's why i cant understand why people insist you making shorter videos. I watched this one in one go and i'm sure that thanks to it being so long i can remember what you said there in the future too.

[BrianHG]

What are the opinions about putting the value/part number inside the part than outside?
Example: https://imgur.com/a/YfDt3Io

When it is a large enough single IC component, where you wont be confused with pin labels, I SOMETIMES place the part number & designator in the middle.  Otherwise, for caps and resistors, ICs with sub-components like simple gates, multi-op-amps, it's always outside, right side up, and organized.

[Cerebus]

What are the opinions about putting the value/part number inside the part than outside?
Example: https://imgur.com/a/YfDt3Io

In the example you give the lack of white space around the value text, and the 90˚ rotation of it both make it harder to read than the counter example. I'd say avoid that style except possibly for small 'illustration' style schematics where you have room for some white space inside the component boundaries.

[jancumps]

Maybe the original designer imported parts of the schematics from somewhere else too? What other reason would there be to mix rectangle and zig-zag resistor symbols?

[SL4P]

One tip I didn’t see, was - if possible -

Place your power busses from the ‘most positive’ at the top, to the ‘most negative’ at the bottom.

You also *implied* layout with the signal flow from left-to-right, but that should also go into the Top 10 important concepts.

Very useful episode to repost! Thanks

[Pentium100]

That's why i cant understand why people insist you making shorter videos.

If a video is too long, people may not have enough time to watch it or they might get bored.

Anyway, when I draw a circuit diagram in Multisim, I usually make it pretty (unless it's something I won't even save), but when I have to do it in Eagle (if I want to order a PCB), then I'm happy it's readable enough so that I can find how everything goes togther as adjusting everything is really annoying. and, in the end, probably nobody else is going to see the schematic anyway.

I always connect everything, using buses if there are a lot of digital signals. I hate it when I have to look around where "DATA_74" goes in a service manual. I can follow a line though. I'd rather read something liek this (attached, a circuit diagram of a tape deck) over the disconnected parts. Even though the tape deck has separate boards and modules, the circuit has them all connected together.

Then again, I am not a professional.

[chris_leyson]

Nice video Dave thanks, it will teach newcomers without much schematic drawing experience one hell of lot. Not only did you show good industry practice but you also explained why it's done that way  Things that perform certain functions have their own blocks and very easy to follow the signal path, nice job very well done.

On a few occasions I've seen schematics drawn from right to left, several of those were because the design engineer was left handed and on one occasion I had a right to left schematic pop up at an interview, I was a bit perplexed trying to follow the signal path and I didn't get the job, no worries though. MInd you on the other hand, no pun intended, I worked with another left handed engineer who drew his schematics from left to right. My late younger brother was left handed and watching him "push" a pen across the page and not smudge think ink was something else.

Do left handed engineers have a preference for drawing from right to left ?

[akowalczyk]

Definitely using this as a teaching tool for new interns/co-ops. Can we have an equivalent for PCBs where you start from a bad one and make it good as well?

It's a better course in schematics than four years of engineering school in the course of an hour and a half. This is really the type of learning that happens when your boss hands you back your schematic covered in red ink.

I mostly avoid pins on the top and bottom, just looks cleaner in general, and lots of named nets rather than long nets connecting blocks. Tends to help when you run out of page space and have to add another, you just switch those net names to off page references.

Also would've been nice to mention multi-symbol parts and separating out hundred-odd-pin chips/connectors into a handful of symbols with logical grouping (i.e. by banks, functions, power etc)

[SL4P]

Sounds like some ideas for a full, multi chapter tutorial...
Perhaps open-source, with fees for republishing...?

[Cerebus]

I haven't had time to watch the video yet, so my apologies if I'm about to suggest something that Dave tackles at length in it.

One rule I'd advocate is to draw typical sub-circuits in standard form.

What I'm talking about is something like a differential pair of transistors. If you draw then in the classic form, shown here as A, then the sub-circuit's function is immediately obvious. If you draw it in non-standard form (B here is one possibility) it takes some thinking before you 'see' a differential pair.



Another examples might be class B complementary output stages. I'm sure that many of you can chip in with design elements that you think should get this kind of treatment.

[nctnico]

And don't draw swastikas...

[mikeselectricstuff]

The thing I hate most is when people just plop down all the symbols, with net names but no interconnect wires at all & call it a schematic.
That, and not providing a PDF version in addition to the format of whatever tool they use

[Mr. Scram]

And don't draw swastikas...

The beauty of technology is that you don't have to worry too much about what's politically acceptable.