Front panel Power and HDD LED Voltages

[Vamprie]

I am thinking of changing out my stock power and HDD LEDs on two of my computers and I am wondering what the voltage coming out of the pins on the motherboards are. The motherboards in the computers are a MSI FM2-A75MA-E35 and a MSI Z170A PC MATE. Thankful for some answers!  

[Electronics Wizardy]

standard 20ma led power. About 3-3.5v

[Quaker]

The stock power and HDD LEDs usually run off the +5v rail. They also usually include a current limiting resistor on-board. Most average LEDs will work just fine, as the motherboard needs to be compatible with the common LEDs that come with various cases.

[Vamprie]

Just now, Electronics Wizardy said:

standard 20ma led power. About 3-3.5v

Thanks for the answer! So will i fry them if they are 2.3 V?

[Vamprie]

1 minute ago, Quaker said:

The stock power and HDD LEDs usually run off the +5v rail. They also usually include a current limiting resistor on-board. Most average LEDs will work just fine, as the motherboard needs to be compatible with the common LEDs that come with various cases.

So my 2.3V LEDs should work?

[Electronics Wizardy]

12 minutes ago, Vamprie said:

So my 2.3V LEDs should work?

Probably, normally leds are current not voltage driven.

[Quaker]

6 minutes ago, Vamprie said:

So my 2.3V LEDs should work?

All LEDs (and all diodes, for that matter) have a basic "junction voltage" which varies around 1.8 to 2.5 volts (or so). The limiting resistor is designed to limit the current through the diode to it's safe operating level. So, yes, they should work unless they are large LEDs designed for high current and high brightness.

[Vamprie]

Just now, Quaker said:

All LEDs (and all diodes, for that matter) have a basic "junction voltage" which varies around 1.8 to 2.5 volts (or so). The limiting resistor is designed to limit the current through the diode to it's safe operating level. So, yes, they should work unless they are large LEDs designed for high current and high brightness.

Okay thanks! I will try if they work

[Vamprie]

1 minute ago, Electronics Wizardy said:

Probably, normally leds are current not voltage driven.

okay

[randombruce]

I know this is way late so hopefully it helps someone else,, voltage usually isn't the killer for leds it is current. Test it with some resistors to control the flow of current. The lower the resistor the brighter. I usually use about 300 ohms to 10k ohms for a resistor value. For adding multiple leds be careful not to use to many because if i remember right the voltage drop across a resistor is .6v on average. So if it is 3.3v you may run out of voltage. 3.3v ~ 5 leds 5v ~ 8.