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Electronic schematic drawing standards? 4

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geekEE

Electrical
Feb 14, 2005
412
Does anyone know of any recognized standards for drawing schematics (circuit diagrams)? For example, on Wikipedia ( it shows a "modern style" of drawing schematic wire junctions, but it does not say if that is from a particular standard.

Or perhaps if the standards out there are too generic, maybe I'm looking for a "style guide" that I can edit for use in my company so that all the EEs are able to reuse each other's schematics more easily.
 
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If you are talking about the US, there really are no standards. Different industry segments have different conventions, but no true standard exist.

IEC/DIN world does have standards.
 
Actually many standards exist. Most codes and standards are cooperating between the US organizations and IEC/ISO standards across the many industries.

I rarely use component level schematics. IEEE 315 reflects some electronic diagram symbols with IEC references. IEEE C95.2 reflects electronic warning shapes. IEEE Y32.9 reflects building wiring symbols.

ISA 5.1 reflects process instrument symbols.

I think that NFPA has a standard for depicting fire, gas and suppression equipment symbols.

Are you specifically looking for micro-processor board level chip type components? I could look in my ham radio handbook to see the source of their symbols. I think that we can identify several standards that you could gather from.


 
There may be some hopeful standards, but there is virtually no consistent complicance with any of them. I've been down this road many times, so pardon my cynicism.

You want "standards"? Try these:

ANSI Y32.9, American National Standard Graphic Symbols for Electrical Wiring and Layout Diagrams Used in Architecture and Building Construction. (I believe this has be deprecated.)

ANSI/IEEE Std 260.3™, American National Standard for Mathematical Signs and Symbols for Use in Physical Sciences and Technology.

ANSI/IEEE Std 260.4™, American National Standard Letter Symbols and Abbreviations for Quantities Used in Acoustics.

IEEE Std 91™, IEEE Standard Graphic Symbols for Logic Functions.5,6

IEEE Std 260.1™, American National Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units).

IEEE Std 280™, IEEE Standard Letter Symbols for Quantities Used in Electrical Science and Electrical Engineering

IEEE Std 315™, IEEE Standard Graphic Symbols for Electrical and Electronics Diagrams (Including Reference Designation Letters).

IEEE Std 945™, IEEE Recommended Practice for Preferred Metric Units for Use in Electrical and Electronics Science and Technology.

IEEE Std 991™, IEEE Standard for Logic Circuit Diagrams.

IEEE/ASTM SI 10, American National Standard for Use of the International System of Units (SI): The Modern Metric System.

ANSI/NECA 100-1999, Symbols for Electrical Construction Drawing
 
Well, I am looking for more of a component-level spec. I'll take a look at IEEE 991. That sounds like it might be closest to what I want.

I've thought that the IEEE 91 standard was kind of odd. I've only seen those symbols used on Texas Instruments data sheets.

Anyway, I'm just trying to see if there's list that has some good schematic drawing practice. There's a few things that really bug me on the schematics I've seen.

Chips that are drawn with no visible power and ground pins are a pain when trying to read a schematic! Also, I'm annoyed when the schematics are all drawn on one sheet so that, even if you print it out on the largest printer in the company, you still need a magnifying glass to read the text.

Thanks guys!
 
I've thought that the IEEE 91 standard was kind of odd. I've only seen those symbols used on Texas Instruments data sheets.

Yep the worst in the industry yep! Yep. uh huh.. Yuck!
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Keith Cress
Flamin Systems, Inc.-
 
There are two electrical that I know of

JIC and IEC standards. Symbols are different from each and so is formating.

JIC used mainly here is US
IEC used in Europe.

I believe when you draw text into autocad it has always been my standard of 1/8" text on a b size print.

 
Then in Europe, there's the EN60617 series (replaces the older BS3939/IEC617 standards).

BS EN 60617-2, Graphical Symbols for Diagrams Part 2: Symbol Elements, Qualifying Symbols and Other Symbols Having General Application

BS EN 60617-3, Graphical Symbols for Diagrams Part 3: Conductors and Connecting Devices

BS EN 60617-5, Graphical Symbols for Diagrams Part 5: Semiconductors and Electron Tubes

BS EN 60617-6, Graphical Symbols for Diagrams Part 6: Production and Conversion of Electrical Energy

BS EN 60617-7, Graphical Symbols for Diagrams Part 7: Switchgear, Controlgear and Protective Devices

BS EN 60617-8, Graphical Symbols for Diagrams Part: 8 Measuring Instruments, Lamps and Signalling Devices

BS EN 60617-10, Graphical Symbols for Diagrams Part 10: Telecommunications: Transmission

BS EN 60617-12, Graphical Symbols for Diagrams - Part 12: Binary Logic Elements

BS EN 60617-13, Graphical Symbols for Diagrams Part 13: Analogue Elements

A.
 
I like the ones on the Wikipedia. Wiggly resistors and coily inductors!

If you use a drawing package like Orcad it will have the symbols built in anyway.

Cross-overs used to be humped bridges. That is now very dated. The modern version just crosses without any hump BUT you must not make 4-branch nodes. Only 3 branches at any node please.

Typically circuit signal flow is left to right and top to bottom. Other than that you can make up your own rules on value labelling, positions of ref and val labels etc.
 
I'm sort of in the same situation...apparently ANSI Y14.15 used to be the standard...is still included on many govenrment manuals for documentation of Electrical and Electronic Diagrams...yet the ANSI/ASME/IEEE website doesn't have a or suggest a replacement for it...Like IEEE 315-1975 = ANSI Y32.2-1975 = CSA z99-1975...so what does ANSI Y14.15 = ??? (AND 14.15a & 14.15b)
 
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