Cells in Series

If the cells are connected in the same direction, the net e.m.f. is the sum of the individual e.m.f. sIf the cells are connected in opposite directions to each other the net e.m.f. is the difference between the e.m.f.s in each direction. For circuits with identical cells in series, the total internal resistance = r × n = n rwhere n is the number of cells.For circuits with n identical cells in parallel:internal resistance = r/nTerminal p.d.

V

=

ε

-

Ir n

n = number of cells