I was recently learning about how a diode works, and I understand how a diode, in it's natural state, develops a sort of "pushback" voltage that pushes against any voltage that is applied, effectively lowering the energy of any electrons that pass (forward voltage). This part makes pretty good sense to me.
However, I fail to understand how to measure this "pushback voltage." Using a multi meter, I tried the setting which I use to measure the voltage out of a battery (200 mV setting), and I noticed that I got different values when testing my small LED's: 3.4 for the Red Led, nothing for the Blue Led, and 9.8 for the green LED. I'm not sure what's going on here. I expected the 3.4 Voltage drop to be normal, but the other LED's don't seem correct. And how can a multi meter even measure the forward voltage of a diode? As in, wouldn't any electrons that had the potential energy to cross against the induced electric field have already made the jump from the n-junction to the p-junction? Any ideas?