Current Electricity Lecture Notes

Introduction

• A detailed study of current electricity will be undertaken.
• Try to understand thoroughly and take careful notes.

Meaning of Current

• Current means the flow of charge.
• In any conductor, charges flow and form a current.
• Current (I) is measured in coulombs.

Types of Current

1. Transient Current

   • Flows for a very short time.

2. Steady Current

   • Flows continuously.

Relationship between Current and Resistance

• The relationship between resistance and current can be understood through Ohm's law.
• Ohm's Law:
  • V = I × R
  • Where
    • V = Voltage
    • I = Current
    • R = Resistance

Kirchhoff's Laws

1. Junction Rule

   • The current entering a junction must equal the current leaving the junction.
   • [ I_{in} = I_{out} ]

2. Voltage Rule

   • The sum of the voltage drops in a closed loop is zero.
   • [ \text{Total Voltage} = 0 ]

Definition of Watt and Power

• Power is measured in watts.
• Power = Voltage × Current = [ P = V × I ]

Electrical Energy

• Energy is utilized in percentage.
• Energy = Power × Time
• Types of energy storage in batteries.

Heating Effect of Current

• When current passes through a resistance, heat is generated.
• [ H = I^2 × R × t ]

Wheatstone Bridge

• An arrangement of four resistances, with one being unknown.
• It is balanced when there is no current at the junction.

Conventions (Trends)

• Trends can be understood through junction and potential sign conventions.

Conclusion

• It is important to encapsulate and understand the principles and practical knowledge of current electricity.
• Be well-prepared to answer questions related to this.

Important Reminders:

• Sign and style of resistance: Increasing resistance decreases current.
• Conservation of charge: Always remember the current entering a junction equals the current leaving it.
• Use both Kirchhoff's laws effectively.

Next Class:

• Conduct an in-depth study of current electricity.

Attention for Participants:

• All students must strictly follow study guidelines.
• Continuous preparation and practice of questions are necessary.

!!! Congratulations, keep up the good work !!!