Basic Electrical Engineering - Lecture Notes

Introduction

• Topic: Basic Electrical Engineering (BEE)
• Purpose: To simplify and explain key concepts for students, especially for CSE students who might find it challenging.

Chapter 1: DC Circuits

• Focus: Basic electrical circuit elements
• Key Elements:
  1. Resistance (R)
  2. Inductance (L)
  3. Capacitance (C)

1. Resistance

• Definition:
  • A property of conductors that opposes the flow of current (or electrons).
• Conductors allow electricity; insulators do not.
• Unit: Ohms (Ω)
• Ohm's Law:
  • Formula: V = IR
  • V = potential difference, I = current, R = resistance.
• Resistance Formula:
  • R is directly proportional to length (l) and inversely proportional to area (A):
    • R ∝ (l/A)
    • R = ρ(l/A), where ρ is resistivity (Ω·m).
• Power Calculation:
  • Power (P) = VI
  • From Ohm's law: P = I²R

2. Inductance

• Definition:
  • A conductor's property that opposes changes in the magnitude or direction of current.
• Unit: Henry (H)
• Formula:
  • V = L(dI/dt)
• Power Calculation:
  • Power (P) = VI
  • P = LI(dI/dt)
• Phasor Diagram:
  • Voltage leads current by 90 degrees (θ = 90°).

3. Capacitance

• Definition:
  • A property of a material to store electric charge.
• Unit: Farad (F)
• Formula:
  • C = Q/V or I = C(dV/dt)
• Power Calculation:
  • Power (P) = VI
  • P = VC(dV/dt)
• Phasor Diagram:
  • Voltage lags current by 90 degrees (θ = 90°).

Summary

• When studying electrical circuit elements:
  1. Write the definition.
  2. State the unit and symbol.
  3. Provide the formula.
  4. Explain the power equation.
  5. Include the phasor diagram.

Conclusion

• Next Topic: Voltage and current sources.
• Encourage students to ask questions and provide feedback on the series.