Definition:Electric Current
Definition
Electric current is the physical process caused by the flow of electrically charged particles, usually electrons.
Thus it is defined as the rate of flow of electric charge:
- $I = \dfrac {\d Q} {\d t}$
It is often treated as a scalar quantity, but more properly it is a vector quantity whose direction is that in which the electrically charged particles are traveling.
Symbol
The usual symbol used to denote an electric current when it is necessary to treat it as a vector quantity is $\mathbf J$.
When only its scalar magnitude is being discussed, the symbols $I$ or $i$ are usually used.
Dimension
Electric current is one of the fundamental dimensions of physics.
In dimensional analysis it is assigned the symbol $\mathsf I$.
Units
The SI base unit of electric current is the ampere $\mathrm A$.
In the CGS unrationalised electromagnetic system, the base unit of electric current is the abampere $\mathrm {abA}$.
In the CGS unrationalised electrostatic system, the base unit of electric current is the statampere $\mathrm {statA}$.
Conversion Factors
\(\ds \) | \(\) | \(\ds 1\) | amperes | |||||||||||
\(\ds \text {corresponds to}\) | \(\) | \(\ds 10^{-1}\) | abampere (or e.m.u., or biot) | |||||||||||
\(\ds \text {corresponds to (approximately)}\) | \(\) | \(\ds 3 \times 10^9\) | statampere (or e.s.u. of electric current) |
Also see
- Results about electric current can be found here.
Sources
- 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $1.$ Units and Abbreviations: $1.2$ SI units $(1)$ Basic units
- 1970: George Arfken: Mathematical Methods for Physicists (2nd ed.) ... (previous) ... (next): Introduction: Electromagnetic Theory
- 1972: George F. Simmons: Differential Equations ... (previous) ... (next): $\S 2.13$: Simple Electric Circuits
- 1976: Ralph J. Smith: Circuits, Devices and Systems (3rd ed.) ... (previous) ... (next): Chapter $1$: Electrical Quantities: Definitions and Laws: The International System of Units: Table $1$-$1$ Basic Quantities