Lecture Notes on Parallel Circuits

Introduction

• Speaker: Paul from TheEngineeringMindset.com
• Topic: Understanding parallel circuits, how they work, and how to calculate them.
• Flow Types: Electron flow (negative to positive) vs Conventional flow (positive to negative)

Connecting Components in Circuits

• Components can be connected in series, parallel, or a combination.
• Series Circuit
  • Electrons have one path to flow.
  • If one component (e.g., a lamp) fails, the whole circuit stops.
  • Example: Fairy lights.
• Parallel Circuit
  • Multiple paths for electron flow.
  • If one path fails, the circuit continues to function.

Voltage in Parallel Circuits

• Measuring Voltage
  • Voltage is measured as a difference between two points.
  • Analogous to water pressure in pipes.
• In parallel circuits, voltage is the same across all components.
• Ohm's Law: Voltage = Current × Resistance
  • Example: 2 amps × 3 ohms = 6 volts.
• Connecting batteries
  • Series: Voltage increases (e.g., two 1.5V batteries = 3V).
  • Parallel: Voltage does not increase but storage capacity does.

Current Flow in Parallel Circuits

• Current (I) measured in amperes (amps).
• Ohm's Law: Current = Voltage / Resistance
  • Example: 1.5 volts / 1 ohm = 1.5 amps.
• When adding more branches:
  • Total current is the sum of currents in all branches.
  • Total current varies based on resistance and voltage.

Calculating Total Resistance in Parallel Circuits

• Total resistance is calculated using:
  • Formula: ![RT = 1 / (1/R1 + 1/R2 + ... + 1/Rn)]
  • Example: Two 10-ohm resistors in parallel have a total resistance of 5 ohms.
• Understanding Conductance as the reciprocal of resistance.

Power Consumption in Parallel Circuits

• Power formulas:
  • Voltage² / Resistance
  • Voltage × Current
• Example: Calculating power consumption for a 10-ohm and a 5-ohm resistor in parallel.
• Total power is the sum of power consumed by each component.

Example Problems

• Problem 1: Calculate total resistance for four resistors in parallel (10Ω, 20Ω, 2Ω, 3Ω).
• Problem 2: Calculate currents in a 3-resistor parallel circuit with a given total current.

Conclusion

• Encouragement to continue learning through additional resources available on TheEngineeringMindset.com and associated social media platforms.