Basic Electrical Engineering Notes + 40 MCQs + Viva | Last-Minute Exam Booster

Basic Electrical Engineering Notes + 40 MCQs + Viva | Last-Minute Exam
Booster
Introduction

These notes cover the basic concepts of Electrical Engineering including current, voltage,
power, circuit elements, KCL, and KVL. Designed for quick revision and exam
preparation, this material includes important formulas, solved problems, MCQs, and viva
questions.
Ideal for last-minute study to help you score better with less time.



LAST-MINUTE REVISION SHEET

🔹 Basic Formulas

 Current: I = Q / t
 Voltage: V = W / Q
 Power: P = VI = I²R = V²/R
 Conductance: G = 1 / R

🔹 Series & Parallel

 Series Resistance: R = R₁ + R₂ + ...
 Parallel Resistance: 1/R = 1/R₁ + 1/R₂ + ...
 Voltage Division:
V₁ = (R₁ / (R₁ + R₂)) × V
 Current Division:
I₁ = (R₂ / (R₁ + R₂)) × I

🔹 Important Laws

 KCL: Sum of currents at a node = 0
 KVL: Sum of voltages in a loop = 0

🔹 Units (Most Asked)

 Current → Ampere (A)
 Voltage → Volt (V)
 Resistance → Ohm (Ω)
 Power → Watt (W)
 Energy → Joule (J)
 Capacitance → Farad (F)
 Inductance → Henry (H)
 Frequency → Hertz (Hz)



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,🔹 Source Types

 Independent Source → Fixed value
 Dependent Source → Depends on circuit variable

Types:

 VCVS, CCVS, VCCS, CCCS

🔹 Key Concepts

 Active elements → Supply energy
 Passive elements → Absorb/store energy
 Conductance ↔ Resistance (reciprocal)

🔹 Quick Memory Tricks

 KCL → Node → Current
 KVL → Loop → Voltage
 Series → Same Current
 Parallel → Same Voltage



COMMON EXAM MISTAKES (VERY IMPORTANT)

Concept Mistakes

 Confusing KCL and KVL
 Mixing up series vs parallel formulas
 Forgetting units (Ohm, Watt, Volt)

Numerical Mistakes

 Wrong parallel resistance calculation
 Missing square in I²R formula
 Sign errors in KVL loops

Theory Mistakes

 Writing incomplete definitions
 Not mentioning units in answers
 Confusing active vs passive elements

Presentation Mistakes

 Not showing steps in numericals
 Skipping diagram when required

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,  Messy calculations

Smart Exam Tips 🎯

 Always write formula first
 Use proper units
 Draw simple circuit diagram
 Double-check sign convention in KVL
 Attempt MCQs carefully (avoid silly errors)

Theory

Electric current is the time rate of change of charge, measured in amperes (A).

dq
Mathematically, i 
dt

So, 1 ampere=1 coulomb/second

Voltage is the energy required to move a unit charge through an element, measured in volts
(V).

dw
Mathematically, v 
dq

So, 1 volt=1 joule/coulomb=1newton-meter/coulomb.

Power is the time rate of expending or absorbing energy, measured in watts (W).

dw dw dq
Mathematically, p   .  v.i
dt dq dt

Note: The law of conservation of energy must be obeyed in any electric circuit. Hence, the
algebraic sum of power in a circuit, at any instant of time must be zero.

Circuit Elements: Circuit elements are of two types in electric circuits namely (a) active
elements and (b) passive elements. An active element is capable of generating energy while
a passive element is not. Typical examples of active elements are generators, batteries,
operational amplifiers etc. Examples of passive elements are resistors, inductors and
capacitors. Passive elements do not have any intrinsic property of boosting an electric signal.
The most important active elements are current or voltage sources which normally deliver
power to the circuit connected to them.

Now sources are of two types: Independent Sources and Dependent Sources. An Independent
Source (ideal) is an active element that provides a specified voltage or current which is
completely independent of other circuit elements. Examples of independent sources are 10 V,
5 A etc. A dependent source (ideal) is also an active element in which the source quantity is
controlled by another voltage or current. Four possible types of dependent sources are

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