• In a circuit that is a closed-loop, such as a series circuit, the current is the?same value at any point
• • This is because the number of electrons per second that passes through one part of the circuit is the same number that passes through any other part

   

• This means that?all?components in a closed-loop have the same current

The current is the same at each point in a closed-loop

• The amount of current flowing around a series circuit depends on two things:
  • The?voltage?of the power source
  • The?number?(and type) of components in the circuit

   

• Increasing?the?voltage?of the power source drives?more?current?around the circuit
  • So, decreasing the voltage of the power source reduces the current

   

• Increasing?the?number?of components in the circuit?increases?the?total?resistance
  • Hence?less?current?flows through the circuit

   

Current will increase if the voltage of the power supply increases, and decreases if the number of components increases (because there will be more resistance)

• At a?junction?in a?parallel?circuit?(where two or more wires meet) the current is?conserved
  • This means the amount of current flowing into the junction is equal to the amount of current flowing out of it

   

• This is because?charge?is conserved

• Note that the current does not always split equally – often there will be more current in some branches than in others
  • The current in each branch will only be identical if the?resistance?of the components along each branch are?identical

   

• Current behaves in this way because it is the?flow of electrons:
  • Electrons are physical matter – they cannot be created or destroyed
  • This means the total number of electrons (and hence current) going around a circuit must remain the same
  • When the electrons reach a junction, however, some of them will go one way and the rest will go the other

   

Current is split at a junction into individual branches

Step 1: Recall that at a junction, the current is conserved

• • This means that the total amount of current flowing into a junction is equal to the total amount flowing out

   

Step 2: Consider the first junction in the circuit where current splits

• • The diagram below shows the first junction in the circuit

   

Step 3: Calculate the missing amount of current

• • Since 10 A flows in to the junction (the total current from the battery), 10 A must flow out of the junction
  • The question says that 6 A flows through ammeter A₁?so the remaining current flowing through ammeter A₂?must be:

   

10 A ? 6 A =?4 A

• • Therefore,?4 A?flows through ammeter A₂