Depends where you added this extra material.
Copper added all over the top: appears as a parallel resistor
Copper added on the ends: appears as series resistance
A strip of copper? appears as parallel resistance
A blob? series-parallel
I'll redraw it to see if that helps you:
simulate this circuit – Schematic created using CircuitLab
There are only two unknown node voltages: \$V_x\$ and \$V_y\$. I think you are saying that you want to find \$V_x\$.
You should be able to work out that \$I_1=I_2+I_3\$, for example. And also that while \$V_y=I_1\cdot R_1\$ (because that's how to ...
a 12V mattress pump
These need a surprising amount of amps in order to run properly. No, 3.5A won't be enough. The lighter socket in a car has amps in the 8A-10A range typically.
You try using an old AT or ATX PC PSU, these have >10A on 12V.
Edit: The crocodile clips work as a series resistor that lowers the current enough keepigng the overcurrent ...
This is from some of the folks who make Kanthal wire.
It goes into some detail about designing things with Kanthal heating wires and elements.
At no point does it tell you how to calculate temperature from voltage and current or voltage and current from temperature because you can't do that.
You have to have the ambient temperature.
You have to have values ...
As Andy mentions, you just need to make your controlling source with a quantized voltage. The simplest way would be using a behavioural voltage with:
V = int(time*N)/N
Where time can also be any other time-dependent waveform you have (e.g. V(x)). As it is it ensures that there are 1/N Volts/step.
There are two main "caveat emptor":
The more steps ...