Electrical Engineering

Part-1

🔌 Basic Electrical Quantities

🔋 1. Voltage (V)

Unit: Volt (V)

Symbol: V or E

Definition: Voltage is the electrical potential difference between two points in a circuit. It represents the "pressure" that pushes electric charges through a conductor.

Formula: V=IR (Ohm’s Law)

Application: Used to specify power supply ratings, battery output, and circuit design.

⚡ 2. Current (I)

Unit: Ampere (A)
Symbol: I
Definition: Current is the flow of electric charge through a conductor. One ampere equals one coulomb of charge passing through a point per second.
Application: Used to size cables, fuses, and circuit breakers.

🔌 3. Power (P)

Unit: Watt (W)
Symbol: P
Definition: Power is the rate at which electrical energy is consumed or produced.
Application: Used to calculate energy consumption and equipment ratings.

🔄 4. Energy (E)

Unit: Watt-hour (Wh) or Kilowatt-hour (kWh)
Symbol: E
Definition: Energy is the total amount of electrical work done over time.
Application: Used in electricity billing and load calculations.

⚛️ 5. Charge (Q)

Unit: Coulomb (C)
Symbol: Q
Definition: Electric charge is the quantity of electricity transported by one ampere in one second.
Application: Fundamental to electrostatics and capacitor design.

🔧 Circuit Properties

🛑 1. Resistance (R)

Unit: Ohm (Ω)
Symbol: R
Definition: Resistance is the opposition a material offers to the flow of electric current.
Application: Used to size resistors, calculate voltage drops, and design load-bearing circuits.

✅ 2. Conductance (G)

Unit: Siemens (S)
Symbol: G
Definition: Conductance is the reciprocal of resistance — it measures how easily electricity flows through a material.
Application: Useful in parallel circuit analysis and material selection.

⚡ 3. Capacitance (C)

Unit: Farad (F)
Symbol: C
Definition: Capacitance is the ability of a system to store electric charge.
Application: Used in filters, timing circuits, and energy storage.

🔁 4. Inductance (L)

Unit: Henry (H)
Symbol: L
Definition: Inductance is the property of a conductor by which a change in current induces an electromotive force (EMF).
Application: Found in transformers, motors, and inductive loads.

🔀 5. Impedance (Z)

Unit: Ohm (Ω)
Symbol: Z
Definition: Impedance is the total opposition to AC current, combining resistance and reactance.
Application: Critical in AC circuit design, audio systems, and power distribution.

🔄 6. Reactance (X)

Unit: Ohm (Ω)
Symbol: X
Definition: Reactance is the opposition to change in current due to inductance or capacitance.
Types:

Inductive Reactance: XL
Capacitive Reactance: XC

Application: Used in tuning circuits, filters, and impedance matching.

🔁 AC Circuit Parameters

🔁 1. Frequency (f)

Unit: Hertz (Hz)
Symbol: f
Definition: Frequency is the number of cycles per second in an AC waveform.
Application: Determines the behavior of inductive and capacitive components. Standard frequency in India is 50 Hz.

⚡ 2. Impedance (Z)

Unit: Ohm (Ω)
Symbol: Z
Definition: Impedance is the total opposition to AC current, combining resistance (R) and reactance (X).

Application: Used in designing AC circuits, audio systems, and power transmission lines.

🔄 3. Reactance (X)

Unit: Ohm (Ω)
Symbol: X
Definition: Reactance is the opposition to the change in current due to inductance or capacitance.
Types:

Inductive Reactance (XL)
Capacitive Reactance (XC)

Application: Critical in filter design, tuning circuits, and impedance matching.

⚙️ Charge and Fields

⚡ 1. Electric Field (E)

Unit: Volt per meter (V/m)
Symbol: E
Definition: The electric field is the force experienced per unit charge at a point in space.
Application: Used in capacitor design, insulation testing, and electrostatics.

🧲 2. Magnetic Field Strength (H)

Unit: Ampere per meter (A/m)
Symbol: H
Definition: Magnetic field strength refers to the intensity of the magnetic field generated by current flow or magnetic materials.
Application: Important in transformer cores, inductors, and magnetic shielding.

🔄 3. Magnetic Flux (Φ)

Unit: Weber (Wb)
Symbol: Φ
Definition: Magnetic flux is the total magnetic field passing through a given surface area.
Application: Used in Faraday’s Law, transformer design, and motor operation.

📏 4. Magnetic Flux Density (B)

Unit: Tesla (T)
Symbol: B
Definition: Magnetic flux density is the amount of magnetic flux per unit area.
Formula: B=ΦA
Application: Used in magnetic circuit analysis and electromagnetic design.

⚛️ 5. Electric Displacement (D)

Unit: Coulomb per square meter (C/m²)
Symbol: D
Definition: Electric displacement represents the amount of electric charge per unit area in a dielectric material.
Application: Relevant in dielectric materials and capacitor behavior.

🌐 6. Electric Flux (ΦE)

Unit: Volt meter (V·m) or Coulomb (C)
Symbol: ΦE
Definition: Electric flux is the total electric field passing through a surface.
Application: Used in Gauss’s Law and electrostatic field analysis.

🔋 7. Electromotive Force (EMF)

Unit: Volt (V)
Symbol: E or E
Definition: EMF is the voltage generated by a source like a battery or generator, which drives current in a circuit.
Application: Central to generator and alternator design, and battery performance.

🔋 Power in AC Systems

⚡ 1. Apparent Power (S)

Unit: Volt-ampere (VA)
Symbol: S
Definition: Apparent power is the total power flowing in an AC circuit, regardless of phase angle.

Application: Used to size transformers, generators, and UPS systems.

🔁 2. Reactive Power (Q)

Unit: Volt-ampere reactive (VAR)
Symbol: Q
Definition: Reactive power is the portion of power that oscillates between source and load due to inductance and capacitance.
Application: Important for power factor correction and reactive load management.

✅ 3. Power Factor (PF)

Unit: Dimensionless (no unit)
Symbol: PF
Definition: Power factor is the ratio of real power to apparent power — a measure of efficiency.

Application: Used to assess system efficiency and reduce energy losses.

🔣 4. Complex Power (S)

Unit: Volt-ampere (VA)
Symbol: S
Definition: Complex power represents both real and reactive power in AC circuits.

Application: Used in power system analysis and load flow studies.

📐 5. Power Density

Unit: Watt per square meter (W/m²)
Definition: Power density is the amount of power delivered or dissipated per unit area.
Application

🧪 Material Properties

⚡ 1. Electric Conductivity (σ)

Unit: Siemens per meter (S/m)
Symbol: σ
Definition: Conductivity measures a material’s ability to conduct electric current.
Application: High conductivity materials like copper and aluminum are used in wiring and busbars.

🛑 2. Electric Resistivity (ρ)

Unit: Ohm meter (Ω·m)
Symbol: ρ
Definition: Resistivity quantifies how strongly a material opposes the flow of electric current.

Application: Used in selecting insulation materials and calculating voltage drops.

📐 3. Permittivity (ε)

Unit: Farad per meter (F/m)
Symbol: ε
Definition: Permittivity measures how easily a material allows electric fields to pass through it.
Application: Critical in capacitor design and dielectric material selection.

🧲 4. Permeability (μ)

Unit: Henry per meter (H/m)
Symbol: μ
Definition: Permeability is the ability of a material to support the formation of a magnetic field within itself.
Application: Important in transformer cores, inductors, and magnetic shielding.

📐 Energy Storage and Transfer

🔋 1. Electric Potential Energy

Unit: Joule (J)
Symbol: U or W
Definition: Electric potential energy is the energy stored due to the position of a charge in an electric field.

Application: Used in capacitor energy calculations, battery storage analysis, and electrostatic systems.

🧮 Advanced Concepts

⚡ 1. Complex Power (S)

Unit: Volt-ampere (VA)
Symbol: S
Definition: Complex power represents both real and reactive power in AC circuits. It’s expressed as a complex number.

Application: Used in load flow studies, power factor correction, and system stability analysis.

📐 2. Power Density

Unit: Watt per square meter (W/m²)
Definition: Power density is the amount of power delivered or dissipated per unit area.
Application: Important in:

Electrical heating systems
Solar panel output ratings
Electromagnetic radiation analysis

🔌 Electrical Load Types and Power Quality

⚡1. Types of Electrical Loads

⚙️ Resistive Load

Examples: Incandescent bulbs, electric heaters
Behavior: Current and voltage are in phase; power factor is 1 (ideal).
Impact: Simple to manage, no reactive power.

🧲 Inductive Load

Examples: Motors, transformers, fans
Behavior: Current lags behind voltage; power factor < 1.
Impact: Generates reactive power, requires compensation (e.g., capacitor banks).

⚡ Capacitive Load

Examples: Capacitor banks, long cables, power factor correction units
Behavior: Current leads voltage; can improve power factor.
Impact: Can cause overvoltage if not balanced properly.

📉 2. Power Quality Parameters

🔁 Harmonics

Definition: Voltage or current waveforms that deviate from pure sine waves due to nonlinear loads.
Sources: UPS systems, VFDs, computers
Impact: Heating of equipment, misoperation of relays, reduced efficiency

⚡ Voltage Fluctuations