Lecture on Series and Parallel Circuits
Introduction
- Explanation of circuits with resistors (can be viewed as light bulbs).
- Two types of circuits: Series and Parallel.
Series Circuits
- Characteristics:
- Only one path for current to flow.
- Light bulbs appear dimmer as more are added.
- Total resistance increases with more resistors.
- Current & Voltage:
- Current is the same through all resistors.
- Use Ohm's Law: ( V = IR ).
Parallel Circuits
- Characteristics:
- Multiple paths for current to flow.
- Light bulbs remain bright as more are added.
- Total resistance decreases with more resistors.
- Current & Voltage:
- Voltage is the same across all resistors.
- Current varies with resistance.
Calculations in Series Circuits
- Finding Total Resistance:
- Sum of all resistances: ( R_{total} = R_1 + R_2 + R_3 + \ldots )
- Using Ohm’s Law:
- ( V = IR ) to find current.
- Voltage Drop:
- Across each resistor: ( V = I \times R )
- Kirchhoff's Voltage Law:
- Sum of voltage drops equals voltage of battery.
- Power Calculations:
- ( P = VI = I^2R = \frac{V^2}{R} )
- Power delivered by battery equals power absorbed by resistors._
Calculations in Parallel Circuits
- Total Resistance:
- ( \frac{1}{R_{total}} = \frac{1}{R_1} + \frac{1}{R_2} + \ldots )
- Current through Resistors:
- Divide voltage by resistance: ( I = \frac{V}{R} )
- Kirchhoff's Current Law:
- Total current leaving battery equals sum of currents through resistors.
- Power Calculations:
- Use ( P = VI ), ( I^2R ), or ( \frac{V^2}{R} ) for each resistor.
- Total power delivered by battery equals sum of power absorbed by each resistor._
Example Problems
- Series Example: Given resistance values, calculate total resistance, voltage drops, and power.
- Parallel Example: Calculate current through each resistor, total current, and power absorbed by resistors.
Key Takeaways
- Series Circuit: One path, same current.
- Parallel Circuit: Multiple paths, same voltage.
- Use Ohm's Law and Kirchhoff's Laws for calculations.
Conclusion: Understanding these principles allows solving various circuit problems effectively. Thank you for attending.