Great posts.
Me? Still learning.
And I still have all my templates.
Bob Wilson CID+
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On Thu, Feb 26, 2015 at 8:42 AM, Ed Murphy <[log in to unmask]> wrote:
> Hey Bill...
>
> Thanx for reminding me just how old I am.... jeesh!!
>
> Ed Murphy CID
>
> -----Original Message-----
> From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
> Brooks, William
> Sent: February-26-15 11:24 AM
> To: [log in to unmask]
> Subject: [DC] The (K) in Cathode
>
> Thanks for the lively discussion. The perception of some is that the
> designers and others on this forum are too busy to talk about things like
> this and that is presumed due to the lack of posting that goes on here...
> You proved them wrong. :)
>
> Bravo!
>
> I have been designing boards since the early 1970's and teach PCB design
> and Electronics Drafting, I have instructed many other designers and
> students before and it amazes me that some folks still speak like they KNOW
> things when in fact they have some tribal knowledge from a previous job
> that becomes the source of misinformation to others because of their very
> confident delivery.
>
> I really like to go back and research things before stating something as
> fact and usually preface my words with "I think" meaning that 'I'm not
> completely sure' if I don't really know for sure. Usually... I do know for
> sure, but there's always that doubt and I like to point to some source for
> my students and colleagues to verify it for themselves.
>
> The 'K designation for 'Cathode' thing, to the best of my knowledge, comes
> from ANSI Y32.2 where it was documented for Diodes of all types. ANSI
> Y32.2.8.5.12 Pin Diode clearly identifies the Anode as (A) and the Cathode
> as (K). Now clearly, ANSI and IEEE and CSA all got their consensus for the
> standard from 'common use' in the industries they were serving.
>
> According to The Dictionary... The word 'Cathode' is mid 19th century:
> from Greek kathodos ‘way down,’ from kata- ‘down’ + hodos ‘way. This was
> proposed by the Rev. William Whewell (1794-1866), English polymath, and
> published by English chemist and physicist Michael Faraday (1791-1867).
>
> I do believe the reason (K) was chosen as the symbol for Cathode to not
> confuse it with the 'C' for the collector of the transistor in schematic
> diagrams. This seems to makes sense... though I was not there when it was
> first established. I used it for a more practical reason... :)
>
> All of us who did standard drafting of Schematics for companies through
> the end of the 20th Century indicated the cathode of a DIODE as (K). If you
> didn't the Drafting Checker would redline the blue line Diazo check print
> in Bright Red INK and tell you to fix it!
>
> Not all PCB designers or Engineers are even aware of or know where the
> symbols for the schematics we use today really came from. But if you did
> drafting 'Back in the day' (like the kids say these days)... you learned
> that your symbols needed to comply with the international standard ANSI
> Y32.2 and your reference designators needed to comply with ANSI Standard
> Y32.16 to be acceptable on your drawing or you were required to change it.
> Proper documentation, especially if you were doing work for the Department
> of Defense (DoD), required this as mandatory. These standards were taught
> in Drafting classes around the world in the colleges and schools. Most of
> today's younger CAD tool users think the CAD companies made them up. They
> didn't. We drew them with lead pencils, drawing templates, drafting
> machines and electric erasers on Vellum long before the CAD companies
> existed.
>
> Standards are pretty important if you want to communicate with a common
> language and thought process.
>
> William Brooks, CID+
> Senior MTS
> 2747 Loker Ave West
> Carlsbad, CA 92010-6603
> 760-930-7212
> Fax: 760.918.8332
> Mobile: 760.216.0170
> E-mail: [log in to unmask]
>
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