Problem with non linear increase in voltage/amperage

[samsanof]

Homework Statement

Please try to keep this simple, I'm only fourteen. I was testing thermometric generators and the voltage and amperage generated at with increased efficiency. I noticed that when I increase the number of generators per circuit, the voltage increase slowed and the amperage increase accelerated. The two were inversely proportional to each other. Does anyone know why the voltage increase slowed down?

I was using .22 gauge iron wire and .22 gauge constantan wire, at a temperature of 353 K.

I have linked an image to the graphs from the experiment.

http://i.imgur.com/4sPIjsG.png

Homework Equations

The Attempt at a Solution

 

[CWatters]

Homework Statement

I noticed that when I increase the number of generators per circuit, the voltage increase slowed and the amperage increase accelerated. The two were inversely proportional to each other. Does anyone know why the voltage increase slowed down?

Adding a generator increases the output voltage and if the load is resistive that increases the current. If the generators have significant internal resistance then the increasing current reduces the voltage all of them deliver not just the new one. That could explain why the voltage increase slows down.

However it doesn't explain why the current increase accelerated. It only explains why the current increases.