HI,

I am working with an energy harvesting cell that generates .5 volts. I want to calculate the current of cell. When I put a 10k ohm load across the cell the voltage drops to .120 volts across the cell and the load. Do I use .5/10000 or .120/10000 to calculate current?
Thanks

 

The latter, actually observed voltage across the load. The unloaded voltage is useful, but not for that calculation.