a) Kirchhoff's second law

a) Kirchhoff’s second law; the conservation of energy

b) Kirchhoff’s first and second laws applied to electrical circuits

Kirchhoff’s second law

• within each closed loop in a circuit → Σε = ΣV

• → Σ energy transferred from the power supply to charge carriers = Σ energy transferred from charge carriers to components

closed loop = a single pathway for current to flow from the negative to the positive terminal of the e.m.f. source

• series circuit → one closed loop

• parallel circuit → more than one closed loop

in a closed loop with more than one source of e.m.f.

• sources with like polarities → add the individual e.m.f.’s

• sources with opposite polarities → subtract the individual e.m.f.’s