Watt within the then-existing system of practical units as "the power conveyed by a current of an Ampère through the difference of potential of a Volt." In October 1908, at the International Conference on Electric Units and Standards in London, so-called "international" definitions were established for practical electrical units. Siemens' definition was adopted as the "international" watt. (Also used: 1 ampere x 1 ohm.) The watt was defined as equal to 10 units of power in the "practical system" of units. The "international units" were dominant from 1909 until 1948. After the 9th General Conference on Weights and Measures in 1948,
Inductance rate of change of current in circuit formula_7. This is the principle behind a "transformer". The sections below will describe self-inductance, the effect of inductance in a single conductor or circuit. Mutual inductance, inductance between circuits, is described in the section at the end. If the current through a conductor with inductance is increasing, a voltage formula_20 will be induced across the conductor with a polarity which opposes the current, as described above (this is in addition to any voltage drop caused by the conductor's resistance). The charges flowing through the circuit lose potential energy moving from the higher voltage