Hello. I have a small solar panel connected to a voltage devider (as shown in the picture) but when I measure the voltage at the Vout point it reads 0.
Image:
https://www.mediafire.com/view/opizwudvrdfjl3w
Weird thing is that when I try to use the arduino's 5v and gnd pins instead of the solar panel's it works as inteded.
Forgot to mention: I'm using two 220 ohms resistors.
I'm a beginner at this, don't know if I'm doing something stupid.
The sun isn't shining on the solar panel, so its only sending a few microamps into your divider.
Try shining a very bright light at it, or doing this outside.
What value are the resistors?
It's currently nighttime here where I live. I tried shining a bright light though. Nothing changed. The resistors are all 220 ohms
Looks like you have the meter probes connected wrong, shouldn't the black probe be in the COM socket and red in the right "V" socket?
Yep, at least one lead needs to be in COM 
(other in voltage of course) Although the 10A amp plug just has very little resistance to COM so it will output a reading but good is something else
But I also think the 220Ω is just wayyyyyyy to low. Those panels can't output very much.
Start by measuring the voltage without any resistors. And if you want a voltage divider on it's output I would go in the order of 10k.
Your are trying to measure a current ! Put the probes in their correct holes.
Since the resistance of the 10A shunt is negligible, it makes no difference whether the black lead is connected to the "COM " or the "10A" sockets, but in this case, the red and black are swapped.
Since it is a digital meter, this makes no difference to the reading except for a "-" or not.
ivan1521:
It's currently night time here where I live. I tried shining a bright light though.
A 'bright light' will be far less bright than sunshine. Your eyes adjust to the change in light intensity, so you don't notice so much the difference between a bright light and sunlight.