Electric Circuits Summary

Parts of a Circuit

• Current: Flow of charge, measured in Amps (A) using an ammeter.
• Voltage: Energy per electron, measured in Volts (V) using a voltmeter.
• Resistance: Impedes current flow, measured in Ohms ($\Omega$) using a resistor.
• Basic Requirements for Electricity:
  • Closed pathway (circuit).
  • Good electrical conductors.
  • Energy source (e.g., battery).
  • Components to use the energy (e.g., light globe).
• Circuit diagrams use symbols for components.
• Series Circuits: Components connected in a single loop.
• Parallel Circuits: Current can split and join, providing multiple paths.

Calculating Energy Efficiency

• Energy Efficiency: Ratio of useful energy to total energy input.
• Efficiency Calculation: $\text{Efficiency} = \frac{\text{Useful output energy (J)}}{\text{Total input energy (J)}} \times 100$

Ohm's Law

• Ohm's Law: Relates Voltage (V), Current (I), and Resistance (R).
• Formula: $V = I \times R$ (Voltage = Current x Resistance)
• Units: Volts = Amperes x Ohms
• Voltage is the force driving current against resistance.

Kirchoff's Laws

• Kirchoff's Loop Law (KVL): Sum of voltages around a loop equals zero.
• Kirchoff's Junction Law (KCL): Sum of currents entering a junction equals the sum of currents leaving the junction.

Series and Parallel Circuits

• Ammeter: Measures current in series.
• Voltmeter: Measures voltage in parallel.
• Series Circuits:
  • Current is the same throughout.
  • Voltage is shared among components.
• Parallel Circuits:
  • Voltage is the same throughout.
  • Current is shared among branches.
• Series Circuits:
  • Total Resistance: Sum of all resistors.
  • Current: Remains the same.
  • Voltage: Divided proportionally.
• Parallel Circuits:
  • Voltage: Remains the same across all components
  • Current: Shared through each lane (Total current = sum of current at each source)