Electromotive Force (E.M.F)
E.m.f in Series
When cells are connected in series, the positive terminal of one is connected to the negative terminals of the other. With this arrangement, a larger emf is obtained in the circuit with improved current.
Etotal = E1 + E2 + E3
rtotal = r1 + r2 + r3
Where r = the internal resistance of the cell.