Electrical current is explained as the rate that a charge flows at. A large current, like a current used to start a car engine, moves a large amount of charge, as compared to a small current like one put out by a calculator, moves a small amount of charge over a longer period of time. This information can be found within the formula I=Q/T. Where Q is the amount of charge passing through a given area, and T is the amount of time it takes.
The SI unit that is used to measure current is ampere (A), which was named after the French physicist Andre-Marie Ampere. Since I=Q/T, we find out that an ampere is equal to one coulomb (pronounced; coo-lomb) per second. Represented as, 1 A = 1 C/s.
The drift velocity (Vd) is the average speed that charges move at. The current I ties into this because it's proportional to drift velocity, in the relationship; I=nqAVd. here, I is the current through the wire of a cross-sectional area A. In this the wire has a free-charge density n, and each carrier has charge q, and drift velocity Vd.
- Electric Current-The rate at which charge flows
- Drift Velocity-The average velocity at which free charges flow in response to an electrical field.