An electric charge is a physical property of electrons and protons in the atoms of matter that gives rise to forces between atoms. The charge is measured in coulomb [C].

The charge of a proton is arbitrarily chosen as positive and has the value of 1.601 x 10-19 C, whereas the charge of an electron is chosen as negative with a value of -1.601 x 10-19 C.

Like charges repel while unlike charges attract each other. The electric charges obey the principle of conservation (i.e., charges cannot be created or destroyed).

A current is the flow of electric charge that is measured by its flow rate as coulombs per second with the units of ampere [A]. An ampere is defined as the flow of charge at the rate of one coulomb per second (1 A = 1 C/s).


1. The Electrical Engineering Handbook – Wai-kai Chen