1. electro-motive force, counter A current going through a circuit often has not only true or ohmic resistance to overcome, but meets an opposing E. M. F. This is termed counter-electro-motive force. It is often treated in calculations as resistance, and is termed spurious resistance. It may be a part of the impedance of a circuit.
In a primary battery hydrogen accumulating on the negative plate develops counter E. M. F. In the voltaic arc the differential heating of the two carbons does the same. The storage battery is changed by a current passing in the opposite direction to its own natural current; the polarity of such a battery is counter E. M. F.
Definitions of electro-motive force, counter
