"Electric Current"

"Current"

• Electric Current is the flow (movement) of electric charge. The SI unit of electric current is the ampere (A), which is equal to a flow of one coulomb of charge per second
• The amount of electric current (measured in amperes) through some surface, e.g., a section through a copper conductor, is defined as the amount of electric charge (measured in coulombs) flowing through that surface over time. If Q is the amount of charge that passed through the surface in the time t, then the average current I is:

I=Q/T

• By making the measurement time T shrink to zero, we get the instantaneous current i(t) as:

i(t)=dQ/dT

• The ampere, the measure of electric current, is an SI base unit so that the coulomb, the measure of electric charge, is derived from the definition of the ampere.