kamhagh
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Why does the raspberry pi have multiple GND pins?

Sat Jan 16, 2016 12:41 pm

I was wondering why does it have multiple Ground pins:?

aren't all grounds supposed to be connected? is this for the current? I see the same thing on PC's PSU connector's for example my graphic's card power has (3 i guess) GNDs, why is it like that?

paulvha
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Re: Why does the raspberry pi have multiple GND pins?

Sat Jan 16, 2016 12:50 pm

they are the same. just making it easier to make multiple connections

weissjd
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Re: Why does the raspberry pi have multiple GND pins?

Sat Jan 16, 2016 1:42 pm

I've wondered that as well. I think the answer is that if you're using jumper wires to build or prototype your project you can't just plug multiple wires into one pin. So it's really just a convenience.

klricks
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Re: Why does the raspberry pi have multiple GND pins?

Sat Jan 16, 2016 1:47 pm

kamhagh wrote:I was wondering why does it have multiple Ground pins:?

aren't all grounds supposed to be connected? is this for the current? I see the same thing on PC's PSU connector's for example my graphic's card power has (3 i guess) GNDs, why is it like that?
All grounds connect to the same point so only one is needed. The GPIO header contains several grounds mostly for convenience. You could have several circuits attached to the RPi and each would need to have a ground connection. Also it can cause problems in if one ground is looped from circuit to circuit.
Multiple grounds in your computer PSU are there to share the load so that one wire does not have to carry all the current. If too much current is allowed then the wire will get hot a possibly burn up.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

kamhagh
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Re: Why does the raspberry pi have multiple GND pins?

Sat Jan 16, 2016 1:58 pm

klricks wrote:
kamhagh wrote:I was wondering why does it have multiple Ground pins:?

aren't all grounds supposed to be connected? is this for the current? I see the same thing on PC's PSU connector's for example my graphic's card power has (3 i guess) GNDs, why is it like that?
All grounds connect to the same point so only one is needed. The GPIO header contains several grounds mostly for convenience. You could have several circuits attached to the RPi and each would need to have a ground connection. Also it can cause problems in if one ground is looped from circuit to circuit.
Multiple grounds in your computer PSU are there to share the load so that one wire does not have to carry all the current. If too much current is allowed then the wire will get hot a possibly burn up.
:O thanks!

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DougieLawson
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Re: Why does the raspberry pi have multiple GND pins?

Sat Jan 16, 2016 3:35 pm

Lots of the GND pins started out as no connection (NC) pins on the original RPis. They are all tied to the same GND bus now. It makes it easy when you've got more than one sensor or GPIO based project that each needs a GND pin.
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dotnet85
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Re: Why does the raspberry pi have multiple GND pins?

Mon Nov 11, 2019 2:53 am

DougieLawson wrote:
Sat Jan 16, 2016 3:35 pm
Lots of the GND pins started out as no connection (NC) pins on the original RPis. They are all tied to the same GND bus now. It makes it easy when you've got more than one sensor or GPIO based project that each needs a GND pin.
thank you
so we can say that it is only for convenience since all are connected to a same ground point

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rpdom
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Re: Why does the raspberry pi have multiple GND pins?

Mon Nov 11, 2019 8:40 am

dotnet85 wrote:
Mon Nov 11, 2019 2:53 am
so we can say that it is only for convenience since all are connected to a same ground point
Yes, that is correct.

The reason they were marked as NC on the first Pi (even though they were still all connected to a common Ground) is that there was a possibility the design could change and the pins be reassigned for something else. Now the design is finalised and they will not be changing.

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