Parallel Circuits and Current Flow

Understanding Parallel Circuits

• Definition of a Parallel Circuit: A parallel circuit is one that has multiple branches, allowing the current to flow through more than one path.
  • Current Splitting: In a parallel circuit, the current splits among the branches. This is different from a series circuit where the current flows through a single path.

Current Flow in Parallel Circuits

• Current Measurement: Current is measured using an ammeter. In a parallel circuit:

  • The total current (
    $I_{total}$
    ) flowing from the cell is the sum of the currents through each branch.
  • Conventional Current: Scientists represent the current flowing from the positive to the negative terminal, known as conventional current.

• Example: In a simple parallel circuit:

  • Current leaving the cell: $I_{total} = 0.3 ext{ amps}$
  • Current in the upper branch: $I_{1} = 0.1 ext{ amps}$
  • Current in the lower branch: $I_{2} = 0.2 ext{ amps}$
  • The sum of the currents in the branches equals the total current:
    $I<em>{1} + I</em>{2} = I_{total}$
    $0.1 + 0.2 = 0.3 ext{ amps}$

Questions for Practice

• Question 1:

  • Given: Current leaving the cell = $0.5 ext{ amps}$
  • Current in the upper branch = $0.3 ext{ amps}$
  • Find the current in the lower branch.
  • Solution:
    $I<em>{lower} = I</em>{total} - I<em>{upper}$$I</em>{lower} = 0.5 - 0.3 = 0.2 ext{ amps}$

• Question 2:

  • Given: Current in the upper branch = $0.4 ext{ amps}$
  • Current in the lower branch = $0.3 ext{ amps}$
  • Find the current leaving the cell.
  • Solution:
    $I<em>{total} = I</em>{upper} + I<em>{lower}$$I</em>{total} = 0.4 + 0.3 = 0.7 ext{ amps}$

Looking Ahead

• Future videos will cover factors determining current flow in different branches of parallel circuits.
• Additional resources: Revision workbook linked in the video for further practice on parallel circuits and current.