[hpsdr] LED polarity (was: OZY Startup Info)

[Christopher T. Day]

Is this even so bad for Zeners? I could read it as the positive voltage
terminal and still get the diode in right.


	Chris - AE6VK


-----Original Message-----
From: Philip Covington [mailto:p.covington at gmail.com] 
Sent: Monday, July 17, 2006 11:48 AM
To: Scott Cowling
Cc: Lyle Johnson; Christopher T. Day; Bill Tracey; HPSDR discussion list
Subject: Re: LED polarity (was: OZY Startup Info)

On 7/17/06, Scott Cowling <scotty at tonks.com> wrote:
> Hi Phil & Lyle,
>
> We ran into the same problem on boards that we design here at work.
Even
> LEDs from the same manufacturer and from the same series have
different
> pins (A or K) marked. If you have a good microscope (or very good
eyes) you
> can see that the die is mounted opposite in the two versions.
>
> We have standardized on marking LED anodes with a "+" sign. It is easy
to
> read and does not imply any correspondence with the marked end.
>
> This does not work for Zener diodes, however. :-) On those, we mark
the
> cathode with a "K".
>
> This method has really cut down on the incidence of "dead LED"
syndrome on
> our prototypes. When we just used a dot or thick bar, we had about a
50%
> chance of getting the parts put on properly. :-)
>
> 73,
> Scotty WA2DFI

Hi Scotty,

I like your suggestion of using the "+" mark.  I was going to do this
initially but put an "a" at the last minute.

73 de Phil N8VB


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