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international ampere

The unit of electric current in the international system of electrical and magnetic units, 1893–1948. Symbol, A_int. It was first adopted at a meeting of the British Association for the Advancement of Science at Edinburgh in 1892, and defined as that unvarying current that would deposit 0.001 118 000 grams of silver per second from a solution of silver nitrate in water. It was sometimes called the silver ampere.

In the United States, Public Bill 105, passed July 12, 1894, made this the legal definition of the ampere in the United States. (current statute)

The amount of silver was chosen to make the international ampere equal to the absolute practical ampere within the limits of precision of the day. Today experimental evidence shows that one international ampere is approximately 0.99985 SI amperes (approximately 0.09985 abamperes).

See history of the ampere.