Electrical Current
The rate of electron flow Q is in Coulombs ( electrons) I = is Amperes (A)
A current of 1A means over 6 billion electrons moving past a point each second.
| Conventional Current | Electron Flow |
|---|---|
| When scientists first began studying circuits, they assumed that positive charges flowed through the wires in a circuit | After scientists learned more about the structure of atoms, they concluded that current consists of electrons (negative charges) |
Direct Current
Current flows in only one direction.
Used in all electrical equipment that is powered by a battery.
Alternating Current
Current changes direction periodically - the charges move back and forth over the same spot and do not actually move from one terminal to another.
Used in all electrical equipment plugged into an outlet.
Ammeter
Used to measure electrical current. Must be connected in series so that all electrons flowing through the wire also have to flow through the ammeter
Kirchhoff’s Current Law
In a closed circuit, the amount of current entering a junction is equal to the amount of current exiting a junction.