Multi-loop Circuits

Multi-loop circuits are the most complex circuits taught in IB Physics. 

• They require use of both of Kirchhoff’s Laws:
  • First Law: the sum of currents going into a junction is equal to the sum of the currents flowing out of that junction.
  • Second Law: around any closed loop in a circuit, the sum of the potential differences (voltage) is 0.
    • Use these laws to derive equations for the current of each resistor, then solve via systems of equations.
      • Do so with matrices.
• When solving multi-loop circuits, draw individual loops for each path the current can take.
  • Dictates direction and signs
  • Denote currents flowing in and out of each junction 
• This type of problem requires practice to master.