# Is this an accurate way to read voltage to an LED?

I have a pot to regulate voltage and my code is reading off analog 0 pin.

It works, but I wonder if I should be placing the jumper from analog 0 after the LED and before R 330?

I’m trying to read how much voltage the LED is getting.
(sorry for sloppy drawing, was done on iPad)

but I wonder if I should be placing the jumper from analog 0 after the LED and before R 330?

If you do you will be getting a measure of how much current the LED is passing, not how much voltage there is across it.

OK, thanks. So I am getting an accurate reading of the voltage going into the LED, right?

Thanks!

No because you have the seriese resistor. If you want to measure accross the LED put the cathode to ground, anode to analogue input and 330R, other end of resistor to your pot.

Thank you. One more question then. In my diagram above, am I accurately reading the volts that are being sent to the LED?

I think if you ask this question again you will make Grumpy_Mike more Grumpy :)

The answer is NO. You are accurately measuring the voltage across the resistor. You need to swap the resistor and the LED. The LED has to be between the point you measure and ground.

OK, thanks Marco.