So I am starting to build circuts to run using my raspberry Pi and have been doing research into electronics circuits.
What I'm trying to work out is how a power bank output current affects the calculations of my circuts.

I know voltage = current * resistance
I know that the current across a serial circuit resister the same
I know that a current across a parrall circuit is the tottal of the current across all the resisters in parrall with eatch other.

But say I had a serial circuit with a 1k, 10k and 2k resister with a 9v batterey how would a powerbank with a 1amp output change the calculations of current in my circuit from a powerbank that outputs 2 amps

 

how would a powerbank with a 1amp output change the calculations of current in my circuit from a powerbank that outputs 2 amps

It doesn't. It's like the car battery that CAN supply 400 amps to start the car, an incandescent brake lamp or 10 mA light a LED (usually a resistor in series with a LED). The "constant" is voltage.

 

Welcome to the forum, Ben Cawley!

Said another way, current, I = E/R, so the current through each resistor is a function of the voltage across it and the resistance. Note the use of the terms through and across are different from the usage in your first post.