Fundamentals of Electrical Engineering: Concepts and Applications
Posted on Jul 5, 2024 in Electronics
Fundamentals of Electrical Engineering
Basic Electrical Quantities
- Voltage
– Unit: Volt
– Symbol: V - Current
– Unit: Ampere
– Symbol: I - Resistance
– Unit: Ohm
– Symbol: Ω (Greek letter Omega) - Electrical Energy
– Unit: Joule (for energy)
– Symbol: E - Electrical Power
– Unit: Watt
– Symbol: P - Inductance
– Unit: Henry
– Symbol: H - Resistivity
– Unit: Ohm-meter
– Symbol: ρ (Greek letter Rho) - Flux Density
– Unit: Tesla
– Symbol: T
Key Concepts in Electricity
- Applications of Electrical Energy
– Electrical energy is used in a wide range of applications, including lighting, heating, transportation (electric vehicles), electronics, and industrial processes. - Advantages of Electrical Energy
– It is clean (if generated from renewable sources), versatile, easy to transport, and can be converted into other forms of energy efficiently. - Difference between AC & DC
– AC (Alternating Current) changes direction periodically, while DC (Direct Current) flows in one direction continuously. - Ohm’s Law
– Ohm’s Law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them (I = V/R). - Electrical Power & Energy
– Electrical Power (P) is the rate at which electrical energy is transferred by an electric circuit. Electrical Energy (E) is the total amount of electrical power used over time. - Circuit Diagram of Commonly Used Electrical Instruments
– This could vary depending on the instrument. Common instruments include voltmeters, ammeters, resistors, capacitors, etc. Diagrams typically show how components are connected. - Electricity
– Electricity is the flow of electric charge (electrons) through a conductor. - Kirchhoff’s Laws
– Kirchhoff’s Current Law (KCL) states that the sum of currents entering a node (or junction) is equal to the sum of currents leaving the node.
– Kirchhoff’s Voltage Law (KVL) states that the sum of electrical potential differences (voltage) around any closed network (loop) is equal to zero. - Series & Parallel Circuits
– In a series circuit, components are connected end-to-end, so the same current flows through each component.
– In a parallel circuit, components are connected across common points, allowing different currents to flow through each branch.
Electronic Components and Devices
- LED
– Full form: Light Emitting Diode.
– Explanation: A semiconductor light source that emits light when current flows through it in the forward direction. - Binary Number System
– A number system based on two digits, 0 and 1. It is widely used in digital electronics and computing. - Semiconductor
– A material that has electrical conductivity between that of a conductor and an insulator. Semiconductors are fundamental to electronics.
Electric Machines
- Working Principle of AC & DC Motors
– AC motors operate on alternating current, utilizing the magnetic field generated by the current in the stator windings to produce rotation.
– DC motors operate on direct current, using the interaction between the magnetic field and current in the rotor to produce torque and rotation. - Difference between Single-Phase and Three-Phase Motors
– Single-phase motors operate on a single AC voltage phase and are simpler in design.
– Three-phase motors operate on three AC voltage phases, providing smoother torque and are more efficient for larger applications. - Digital Logic Gates
– Digital logic gates are fundamental building blocks of digital circuits. They perform Boolean logic operations (AND, OR, NOT, etc.) on input signals to produce an output. - Difference between Servo and Stepper Motors
– Servo motors provide precise control over position, speed, and torque, typically used in applications requiring high accuracy.
– Stepper motors move in discrete steps, controlled by electrical pulses, suitable for applications requiring precise positioning. - Advantages of AC over DC
– AC can be easily transformed (changed in voltage level) using transformers, allowing for efficient transmission and distribution over long distances.
– AC motors are simpler and more reliable for industrial applications. - Why AC Voltage is Preferred over DC Voltage
– AC voltage can be easily converted to different voltages using transformers.
– AC is more suitable for long-distance transmission due to lower energy losses. - Thyristor
– A semiconductor device with four layers of alternating P-type and N-type material. It acts as a switch, conducting current when triggered. - Electric Machine
– An electric machine is a device that converts electrical energy into mechanical energy (motor) or vice versa (generator). - Types of Electric Machines
– Electric machines include motors (AC and DC motors) and generators (AC and DC generators), each designed for specific applications.
Circuit Theorems and Energy Storage
- Superposition Theorem
– Superposition theorem states that in a linear electric circuit with multiple sources, the response (voltage or current) in any branch is the algebraic sum of the responses due to each source acting alone, while all other sources are replaced by their internal impedances. - Where is Thevenin Theorem Used?
– Thevenin’s theorem is used to simplify complex electrical networks into simpler equivalent circuits, facilitating easier analysis and design. - Thevenin Theorem
– Thevenin’s theorem states that any linear electrical network with voltage and current sources and resistances can be replaced by an equivalent circuit consisting of a single voltage source (Thevenin voltage) in series with a single resistor (Thevenin resistance). - Energy Storage Systems
– Energy storage systems store electrical energy for later use. They include batteries, capacitors, and inductors. - Types and Applications of Energy Storage Systems
– Types include chemical (batteries), electrostatic (capacitors), and electromagnetic (inductors). Applications range from portable electronics to grid-level storage for renewable energy integration.
