DC power jack design decision: 2.1mm ID or 2.5mm ID?????

Hello all,  I just received this great reply directly in email, so I thought I would share it with everyone...

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Steve,

   I couldn't find a way to reply to your post so I'll just email you. Regarding the dilemna about DC power jacks, after I designed in a 2.5 MM jack to use some of the power supplies that I though were so common I found myself making many adapters from 2.5 to 2.1 mm. I would suggest that you design in center positive 2.1 MM jacks as this seems to be the most common wall adapter available for 12VDC. If I ever do it again I will make sure that I do the same. Hope this helps, Lloyd Carver Austin Electronics austinelex.com

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Thank you Lloyd Carver!!

So, why is no one else answering this question?  After talking with Emerson Network Power they said that they had done the research and have determined that 2.5mm is the most popular, so therefore they are hopping on that bandwagon.  You can see that its true here...

http://www.powerconversion.com/products/websheet/414/DA4-US

http://www.powerconversion.com/products/websheet/400/DA12-M-Medical

http://www.powerconversion.com/products/websheet/146/DA16

http://www.powerconversion.com/products/websheet/431/DA18-M-Medical

They are all 2.5mm except the 12w model, which offers both 2.5mm and 2.1mm.  So, I have gotten definitely contradicting opinions from people and yet you viewers remain silent.  We are getting ready to launch a family of consumer widgets and it would be nice to confidently move ahead with the right solution.....oh wait, this is engineering...there is no such thing as a right solution!!!

Thank you for any suggestions!!.... changing after we make several thousand will be much more difficult!

Hi Steve, It's an interesting question, one which I have wondered about myself.  2.5mm is about 1/10 inch and I wonder if this is a clue?  It maybe market dependant perhaps? - markets in locations that tend to imperial measurements might prefer 2.5mm, being the equalivant of 1/10".  Having said that it doesn't make much sense that markets that tend towards metric would prefer 2.1mm.  Nice lighting effects on your website!  I use to work for a company, here in New Zealand, that manufactured all the LED lighting products for Hella  for world wide distribution.  Regards, Chris

Hi Steve, It's an interesting question, one which I have wondered about myself.  2.5mm is about 1/10 inch and I wonder if this is a clue?  It maybe market dependant perhaps? - markets in locations that tend to imperial measurements might prefer 2.5mm, being the equalivant of 1/10".  Having said that it doesn't make much sense that markets that tend towards metric would prefer 2.1mm.  Nice lighting effects on your website!  I use to work for a company, here in New Zealand, that manufactured all the LED lighting products for Hella  for world wide distribution.  Regards, Chris

I don't think you will have any issues whichever you choose, they have both been around for years and will continue to do so. From my own research I settled on 2.1mm as looking at catalogues to ensure second and third source options it seemed to be the size I could most easily find several manufacturers and suppliers covering in the same footprint.