Electric Current and Potential Difference

Current: rate of flow of charge round the circuit, current will only flow through a component if there is a voltage across that component
1. Unit: ampere (A)
Voltage (potential difference): the driving force which pushes the current round
1. Unit: volt (V)= 1 joule/coulomb
Resistance: Anything in a circuit that can slow the flow down
1. Unit: ohms (Ω)
The voltage and the resistance are doing opposite things so they decide how big the current will be. If you increase the voltage in a circuit then more current will flow, and if you increase the resistance then the current will decrease and slow the current down
Potential difference (Voltage): Energy transferred per unit of charge passed
1. Energy is transferred due to a change in potential difference
  1. The energy from the battery/cell is supplied to raise it through the voltage
    1. The charge lowers whenever it goes through a component anywhere in the circuit
The bigger the voltage/potential difference, the more energy transferred for a given amount of charge passing through a circuit
In a circuit a battery with a bigger voltage will supply more energy for every coulomb of charge that flows around it
Current is conserved at a junction in a parallel circuit so no current is lost or used up. At junctions current either splits or re-joins at points in the circuit
1. This means that the total current entering a junction is equal to the total current leaving a junction

Resource summary

	Created by milliewernyj17 almost 11 years ago