Electrical Circuits: Series and Parallel

Types of Electrical Circuits

• Series Circuit:

  • Components are connected end to end, forming a loop.
  • Current flows through one path.
  • Examples include a simple loop with a cell and two bulbs.

• Parallel Circuit:

  • Components are connected side by side.
  • Current divides into multiple paths.
  • Examples include a circuit with a cell and two bulbs, connected in parallel.

Key Concepts

Voltage

• Measure of electrical push from the battery.
• Energy per packet of electrons (measured in joules) referred to as coulombs.
• Voltmeter:
  • Measures voltage across components.
  • Always connected in parallel.

Current

• Flow of negatively charged electrons.
• Analogous to water flow in pipes.
• Measured in coulombs per second or amps.
• Ammeter:
  • Measures current in a circuit.
  • Must be connected in series.

Resistance

• Opposition to current flow in a circuit.
• Measured in ohms (Ω).
• Higher resistance = more difficult current flow.

Circuit Rules and Calculations

Series Circuits

• Voltage from power supply is shared between components.
• Same current flows through each component.
• Total resistance = sum of individual resistances.

Parallel Circuits

• Voltage is the same across each component.
• Total current = sum of currents through each component.
• Total resistance is less than the smallest individual resistance.

Practical Examples

• Voltage Calculation:

  • Each cell provides 1.5 volts.
  • For four cells, calculate total potential difference.

• Current Calculation:

  • Current through lamp = 0.20 amps.
  • Current through resistor = 0.10 amp.
  • Calculate the reading on the ammeter.

Calculating Resistance in Parallel

• Formula for two resistors in parallel:
  • For example, two 3 ohm resistors:
    • Total resistance = 1.5 ohms.
  • For example, resistors of 10 ohms and 5 ohms:
    • Total resistance = 3.33 ohms.

Summary:

• Understand the differences between series and parallel circuits.
• Learn to calculate resistance using rules and formulas.