The flow of charged particles produces electric current. The size of the electric current is equal to the rate of flow of charge.I = ΔQ /ΔtI is electric current in amperes (A), ΔQ is electric charge transferred in coulombs (C). Electric current is the amount of charge passing a given point in a circuit per unit time (per second). 1 ampere is 1 coulomb of charge passing a given point in one second.1 A = 1 Cs-1An ammeter is used to measure electric current. Ammeters are placed in series and they should have negligible resistance so it does not decrease the current it is measuring. Electrons move around the circuit from the negative to positive terminal. However conventional current is from positive to negative.