Electromotive force and Kirchhoff’s Voltage Law
From our earlier discussion we know that
......................(3.11)
Using the point form of Ohm’s Law we can write
......................(3.12)
Thus we observe that an electrostatic field cannot maintain a steady current in a closed circuit. Motion of charged carriers in a circuit, which is required to establish a steady current, is a dissipative process while charges moving in a closed path in a conservative electrostatic field neither gain nor lose energy after completing one trip round the circuit. The loss of energy is normally supplied by sources of non-conservative field (e.g. battery, generator, photovoltaic cell etc) and provides a driving force for the carriers.
Fig 3.2: Typical Battery