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LED light from PC power button

Posted: Sun Mar 10, 2019 6:40 am
by moryoav
Hi,

I have one of these buttons.

I've successfully hooked up the 2 power button pins to pins 3 and 4 in the GPIO and a few lines of python later I have a button that turns the device on and off (holding it for a few seconds to turn the pi off). That works great.
The button also has an LED light. In the PC motherboard you just connect the pins to the motherboard header. My question, can I assume that this led is meant for the appropriate voltages and I can connect it directly to the GPIO pins without a resistor? I would then just program the LED to light up when the device is on.

Thanks!

Re: LED light from PC power button

Posted: Sun Mar 10, 2019 9:31 am
by drgeoff
I would not assume that there is a resistor present.

Re: LED light from PC power button

Posted: Sun Mar 10, 2019 10:25 am
by pcmanbob
I built PC's for many years and in all that time I never saw a resistor in series with any of the case LED's, as far as I am aware all current limiting was done on the motherboard, so this button will not have any resistors in the LED circuit if it follows the same standard.