What is the SI unit of electric current?

The SI unit of electric current is the ampere (A).

Electric current is the flow of electric charge through a conductor. The SI unit of electric current, the ampere, is defined as the constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed one metre apart in a vacuum, would produce between these conductors a force equal to 2 x 10^-7 newton per metre of length.

One ampere of current is equivalent to one coulomb of charge passing through a conductor in one second. This relationship is expressed in the equation I = Q/t, where I is the current in amperes, Q is the charge in coulombs, and t is the time in seconds.

Electric current is measured using an ammeter, which is connected in series with the circuit. The ammeter must have a very low resistance to avoid altering the current being measured.

Understanding the unit of electric current is important in many areas of physics, including electromagnetism and electronics. It is also essential in practical applications such as electrical wiring and the design of electrical circuits.