How is charge defined?

If you want to talk about charge then its usually measured in Coulombs and is primarily a quantity (6000000000000000000 electrons). If one amp is flowing in a circuit then one coulomb of charge is flowing past a point in one second.

Electric charge is measured in coulombs (C) and is defined as the flow of charge in a time of 1 second (s) when the current is 1 ampere (A).

Charge (Q) = current (I) x time (t)

therefore 1C = 1A x 1s

Electrons are negatively charged and an electron has a charge of 1.6 x 10^-19.

So 1 coulomb of charge is produced from 6.25 x 10^18 electrons.

Charge (Q) is a fundamental physical property of particles. Some particles are positively charged, like protons, and some are negatively charged, like electrons.

Unlike charges are attracted to each other (+ & -) and like charges repel each other (+ & +; - &- ).

Charge carriers are anything that carries a charge, such as ions, charged particles or molten metals. But mostly we consider the charge of electrons in an electrical circuit.