Current in Circuits | Physics for GCSE/IGCSE - Year 11 PDF Download

Current in Series Circuits

• In a closed-loop circuit like a series circuit, the current remains constant throughout. 
  • This consistency arises from the fact that the quantity of electrons flowing through any segment per second equals that flowing through any other part. 
• Consequently, all elements within a closed-loop exhibit identical current.

• The quantity of current circulating through a series circuit is contingent on two key factors:
  • The voltage of the power source
  • The resistance of the circuit components
• Higher voltage from the power source results in increased current flow within the circuit.
  • Decreasing the voltage from the power source leads to a reduction in current.
• Increasing the number of components in the circuit raises the total resistance.
  • Thus, the circuit experiences a decrease in current flow.

Current in Parallel Circuits

• Parallel circuits involve multiple components connected in separate branches.

• The advantages of parallel circuits include:
  • Components can be controlled individually via their own switches.
  • If one component malfunctions, the others can continue operating.
• Current divides in a parallel circuit, with portions flowing through different branches.
• As a result, the current in each branch is less than that from the power supply.

Junctions in Parallel Circuits

• At a junction within a parallel circuit, where multiple wires intersect, the principle of current conservation applies. 
  • This implies that the incoming current at the junction equals the outgoing current.
• This conservation principle arises from the fact that charge remains constant. 
• It's important to note that current distribution may not always be uniform; certain branches may carry more current than others. Uniform current distribution occurs only when the resistance across each branch is identical. 
• The behavior of current is governed by the flow of electrons, which are physical entities subject to the law of conservation of matter. 
  • Therefore, the total number of electrons, and consequently the current, within a circuit remains constant. 
  • Upon reaching a junction, electrons diverge, with some electrons moving in one direction and the remainder in another.