Defining Electric Current
- Electric current is the flow of charge carriers and is measured in units of amperes (A) or amps
- Charge can be either positive or negative
- When two oppositely charged conductors are connected together (by a length of wire), charge will flow between the two conductors, causing a current
Charge can flow between two conductors. The direction of conventional current in a metal is from positive to negative
- In electrical wires, the current is a flow of electrons
- Electrons are negatively charged; they flow away from the negative terminal of a cell towards the positive terminal
- Conventional current is defined as the flow of positive charge from the positive terminal of a cell to the negative terminal
- This is the opposite to the direction of electron flow, as conventional current was described before electric current was really understood
By definition, conventional current always goes from positive to negative (even though electrons go the other way)
- There are several examples of electric currents, including in household wiring and electrical appliances
- Current is measured using an ammeter
- Ammeters should always be connected in series with the part of the circuit you wish to measure the current through
An ammeter can be used to measure the current around a circuit and always connected in series