how one can identify the polarity of the pin of the connector for power supply.

[Meenu bhardwaj]

i am building a board for atxmega in which i am using a 2 pin female connector for 5v power supply one question struck in my mind if the polarity of the 2 wires in which one is positive and other is ground is changed what will happen n if i used same colour wires or opposite wires then otherperson come to know about which wire is for ground n which is for power ????????? plz help me ......

 

[manofchalk]

Can you more clearly state which plug/connection you are talking about? I'm thinking you are talking about the connection between the wall and back of the PSU but I am not sure.

 

[FinneousPJ]

With a multimeter.

 

[Meenu bhardwaj]

Can you more clearly state which plug/connection you are talking about? I'm thinking you are talking about the connection between the wall and back of the PSU but I am not sure.

see in my eagle schematics i have connected the connector with the regulator in which let i connected pin 1 to 5v n pin 2 to gnd so when i place it on the pcb i connect female header to the male header and then the female header to the 5v power supply but for the wires coming out of the female header how one can identify which has to connect to positive and which with gnd...i hope u got my question

 

[manofchalk]

Ok, that has confused me even more so. Are we even talking computers here? Which component is power coming from and its going to what? As far as I know nothing connects to the PSU through 2pin headers. And the 5v rail is (I think) responsible for HDD's and any molex connections, none of which are two pin.

Generally the positive wire will be an unusual colour to the negative. Look on the plug itself, if it has a small arrow underneath one of the "holes" in the plug, that generally indicates positive as well.

 

[Meenu bhardwaj]

here i am talking about microcontrollers i m designing a board which consists of atxmega256a3 microcontroller chip and to provide 5v supply to it i need a 2 pin connector yeah it has an arrow showing the pin number 1 but how a totally unknown person know which pin is connected to power supply n which is to gnd

 

[manofchalk]

So non-standard parts. You are literally building the machine.

In that case I have no clue.
Maybe try putting a wire around/inside the header you think is negative, and have it run through a light-bulb or something, with the bulbs leading to ground. If it works, you'v found the negative (or at-least, active) wire, so it would make sense the others positive. That's one way I can think of figuring it out.

I assume you have scoured whatever guides or instructions are associated with these chips?

 

[Meenu bhardwaj]

thanks for ur answers....

 

[FinneousPJ]

I don't understand why don't you just test it.