Circuit elements are said to be in series if they are connected so that one current flows in turn through each of them (see diagram).
For n resistors in series the total resistance, R, is given by:
where r1, r2, …rn are the values of the individual resistors. The resistors thus behave collectively as one large resistance.
For n capacitors in series the total capacitance, C, is given by:
where c1, c2, …cn are the individual capacitances.
Machines, transformers, and cells are said to be in series when terminals of opposite polarity are connected together to form a chain. Several cells connected together in series add the values of the emfs and can therefore supply a larger voltage.
Compare parallel.
![series](Images/oree/doc/10.1093/acref/9780198725725.001.0001/acref-9780198725725-graphic-302-full.gif)