Amount of electric charge flowing past a specified circuit point per unit time. The metric system unit for this quantity is "A" (Ampere). The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 × 10⁻¹⁹ when expressed in the unit C, which is equal to A s, where the second is defined in terms of ∆νCs. This definition implies the exact relation e = 1.602 176 634 × 10⁻¹⁹ A s. Inverting this relation gives an exact expression for the unit ampere in terms of the defining constants e and ∆νCs: 1 A = (e / 1.602 176 634 × 10⁻¹⁹) s⁻¹

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SI Base Unit