Question

what is the difference between unit of electric current and very smaller unit of electric current​

Answer 1

The SI unit of charge is coulomb and therefore current is measured in coulomb per second which has been given the name ampere (Symbol A) in honour of the french physicist Andre Ampere.

We define one ampere as the current which flows in a conductor when one Colombo of charge passes in one second

1A=1C/1s=1Cs-1

To express a weak current the smaller unit of current are milli-ampere(mA) and micro ampere which are related to ampere(A) as follow :

1mA =10upon 3A and 1 micro ampere =10 upon 6A.