Ampere

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The ampere (symbol: A), often shortened to amp, is the unit of electric current in the International System of Units (SI). One ampere is equal to 1 coulomb (C) moving past a point per second. It is named after French mathematician and physicist André-Marie Ampère (1775–1836), considered the father of electromagnetism along with Danish physicist Hans Christian Ørsted. As of the 2019 revision of the SI, the ampere is defined by fixing the elementary charge e to be exactly 1.602176634×10−19 C, which means an ampere is an electric current equivalent to 1019 elementary charges moving every 1.602176634 seconds, or approximately 6.241509074×1018 elementary charges moving in a second. Prior to the redefinition, the ampere was defined as the current passing through two parallel wires 1 metre apart that produces between these wires a force of 2×10−7 newtons per metre. The earlier CGS system has two units of current, one structured similarly to the one of the SI and the other using Coulomb's law...

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