Circuit Theory/Superposition

Goal

edit

Split multisource circuit into smaller, simpler circuits, compute current or voltage and add.

Procedure

edit

Pick one source, turn off all or set to zero all others:

  • Set Voltage Sources to V=0, doesn't care about current so is a short
  • Set Current Sources to I=0, doesn't care about the voltage so turns into an open

Example 1

edit

Find the current through the 3 ohm resistor assuming moving left to right is positive:

The total current in the direction shown on the original diagram is going to be:  

Example 2

edit

Find the current through the 4 ohm resistor assuming moving left to right is positive:

 

Simulation at circuit lab confirms the answer: