Basically, A closed and contineous path of an electrical current is called an electric circuit. Normaly an electric circuit consists of some electric power source, switches, wire or cables and electric devices like bulbs, resistors tubelight etc.
The SI unit of electric current is ampere denoted by character "A". Or we can say that Ampere is one of the SI base units for electric current. It measures the flow of electric charge across a surface at the rate of one coulomb per second. When one-coulamb charge flow through an electric device in a circuit in one second, then the current flowing through the device is said to be 1 Ampire.
1 Ampire = 1Coulamb / 1 second
Since the charge is measured in coulombs and time in seconds, so the unit is coulomb/Sec (C/s) or amp. Meanwhile, the formula for electric current is given as follows:
I = V/R
Where, I = Electric Current, V = Voltage and R = Resistance of the material
Some Other Current Units
||V or E
||R or Ω
||L or H
||G or ℧