Two Black Wires question on wiki

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WillAdams
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Two Black Wires question on wiki

Post by WillAdams » Tue Jun 11, 2013 1:08 pm

Dbdukes asked:
Two Black Wires?

The pictures for this batch show the DC connector pig tail with a red wire (+) and a black wire (-). The pig tail I received with my kit has two black wires (one pure black, one black with a white stripe). I'm trying to figure out which one is the + and which one is -. Googling has not yielded results.
on the talk page

http://www.shapeoko.com/wiki/index.php/ ... ch_4_and_5
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

cvoinescu
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Re: Two Black Wires question on wiki

Post by cvoinescu » Tue Jun 11, 2013 1:27 pm

Is it a barrel jack (like this one)? If so, the center pin is positive. This has been practically universal ever since germanium transistors fell out of fashion.

Or, to be extra-sure, plug the supply into the pigtail, make sure the wires aren't touching, plug the supply in, and use your multimeter to measure.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

NickKK
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Re: Two Black Wires question on wiki

Post by NickKK » Tue Jun 11, 2013 1:31 pm

... aaand it's been common to use the black wire with the white stribe for PLUS (+) since the dawn of mankind :-)
ShapeOko #1738 Rev. F

WillAdams
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Re: Two Black Wires question on wiki

Post by WillAdams » Tue Jun 11, 2013 1:31 pm

It should be this one:

Image
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

NickKK
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Re: Two Black Wires question on wiki

Post by NickKK » Tue Jun 11, 2013 1:39 pm

If RED and BLACK then PLUS (+) is the RED wire.
If BLACK and BLACK (with white stribe) then BLACK WITH WHITE STRIBE is PLUS (+).

It's that simple :-)
ShapeOko #1738 Rev. F

mmmmmick2011
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Re: Two Black Wires question on wiki

Post by mmmmmick2011 » Wed Jun 12, 2013 7:32 pm

Thanks for the answers, cvoinescu and NickKK.
I think I could have done without the sarcastic "look-down-at-nose" augmentations, such as "dawn of..." and "practically..." After all, I don't know much about electronics, and I'm willing to bet you only know a little bit about Anthropology!!!

cvoinescu
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Re: Two Black Wires question on wiki

Post by cvoinescu » Wed Jun 12, 2013 10:03 pm

No sarcasm from me. It was an honest qualifier: the convention is not universal these days, just nearly so. There still is the odd device out there that is center-negative, and some take low-voltage AC using the same connector. I was just adding the useless piece of trivia that center-negative used to be the norm in the age of germanium transistors (while bipolar silicon transistors are easier to manufacture in NPN, germanium favoured PNP, so schematics had reverse polarity back in the day, with positive ground and negative VCC).
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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