If it can, what kind would I get? Two potatoes if that helps. I know you have to have a fair amount of potatoes to power an LED, so outside of having eight potatoes wired up, I thought maybe two could charge a capacitor.
I thought if I could charge a capacitor with a potato or two, then I could let the capacitor charge up and light the LED, since a continuous flow from a couple of potatoes isn't enough to power the LED alone (I have to have a bunch of taters for that.)
Yes, that should work. Use a large value electrolytic capacitor, like 2200uF or 3300uF (voltage common value 16V, but any voltage would work.) Let it charge for half a minute.
You'll need at least two taters wired in series, and use a red LED, since those only need about 1.7V or so. (Green and blue LEDs need much higher forward voltage.)
There are two problems here.
a) The ultimate voltage you are going to get from one tater cell depends on the composition of the metal electrodes that you use in your cell.
b) The amount of current that you can generate depends on the area of the electrodes and the composition of the electrolyte (the tater).
The trick here is to use a capacitor to store up the current until the voltage across the capacitor reaches that in part a. Then you can use the capacitor to illuminate a LED. How long you can illuminate it for and how long the capacitor takes to recharge depends on the size of the capacitor, the current requirement of the LED and the current limits set by part b.
Good luck with this experiment and please let us know if any particular potato gives better results.
If you are going to use this to power microelectronic can I suggest the megachip variety, if you have sunshine available how about the solara variety.
