What PSU MOLEX PIN voltage

[Junwei]

From what i know, the molex 4pin from psu output 12v however isnt the pin configuration 12v,gnd,gnd,5v. What will the 5v do when plugged into a 12V LED .

[Mira Yurizaki]

It either won't turn on or it won't be as bright.

[aeroencychris]

Nothing?

It's just for devices that happen to need 5v instead of/alongside 12v. Are you saying using 5v instead of 12v?

But yes:

[pagani123]

just will not be as bright 

[Junwei]

18 minutes ago, Maybach123 said:

just will not be as bright 

 

22 minutes ago, cdsboy2000 said:

Nothing?

It's just for devices that happen to need 5v instead of/alongside 12v. Are you saying using 5v instead of 12v?

But yes:

 

23 minutes ago, M.Yurizaki said:

It either won't turn on or it won't be as bright.

Sorry if i did not make myself clear. What i meant was i have a 12V  LED 4pin to connect to the molex pin. Was just curious that since the 12V only require the Yellow wire and ground wouldn't the 5V (redundant i guess in this case) affect the voltage or something

[Junwei]

I also have a led fan that require a molex pin to connect. How the device know which voltage to take in.

[Mira Yurizaki]

33 minutes ago, Junwei said:

Sorry if i did not make myself clear. What i meant was i have a 12V  LED 4pin to connect to the molex pin. Was just curious that since the 12V only require the Yellow wire and ground wouldn't the 5V (redundant i guess in this case) affect the voltage or something

No. It only affects the voltage of the part in question if you connect it to the part's return lead (which is supposed to go into ground).

[Junwei]

17 minutes ago, M.Yurizaki said:

No. It only affects the voltage of the part in question if you connect it to the part's return lead (which is supposed to go into ground).

Meaning the 5V will go to ground? Sorry still a newbie..

[Mira Yurizaki]

Just now, Junwei said:

Meaning the 5V will go to ground? Sorry still a newbie..

Let's simplify this. An electrical part need an input lead and a return lead for power. The combination of these leads determines the voltage the part is exposed to. Since on a Molex we have 12V, 5V, and 0V (ground), you have these combinations:

Input	Return	Result
12	0	12
12	5	7
12	12	0
5	0	5
5	5	0
5	12	-7
0	0	0
0	5	-5
0	12	-12

The voltages only affect each other if they're actually connected to the part. Though even if the part in question uses the 12V, 5V and ground, it could just mean some things use 12V and some things use 5V and they never interact.