Demonstration model of a moving iron
The ampere (
The International System of Units defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier
The ampere is defined by taking the fixed numerical value of the
The SI unit of charge, the
In general, charge Q is determined by steady current I flowing for a time t as Q = It.
Constant, instantaneous and average current are expressed in amperes (as in "the charging current is 1.2 A") and the charge accumulated (or passed through a circuit) over a period of time is expressed in coulombs (as in "the