# Unit 3: Current electricity

## About Course

Course Title: Exploring Current Electricity: Principles and Applications

Course Description:

Unit 3: Current Electricity delves into the fundamental principles governing the flow of electric current in conductive materials. Through theoretical instruction, laboratory experiments, and practical demonstrations, students will explore concepts such as electric current, Ohm’s law, electrical resistance, and DC circuits. The unit will cover different types of electrical circuits, their characteristics, and the applications of current electricity in physics, engineering, and everyday life.

Course Outline:

1. Introduction to Electric Current

– Overview of electric current: flow of electric charge through a conductor

– Types of electric current: direct current (DC) and alternating current (AC)

– Electric current density: current per unit area in a conductor

– Conservation of electric charge and continuity equation for current

2. Ohm’s Law and Electrical Resistance

– Ohm’s law: relationship between voltage, current, and resistance in an electrical circuit (V = IR)

– Resistance: property of a material to resist the flow of electric current

– Factors affecting resistance: material, length, cross-sectional area, and temperature

– Temperature dependence of resistance and temperature coefficient of resistance

3. Electrical Circuits and Circuit Elements

– Electric circuit: closed loop through which electric current can flow

– Circuit elements: voltage sources, resistors, capacitors, inductors, and switches

– Series circuits: components connected in a single path, sharing the same current

– Parallel circuits: components connected across common points, sharing the same voltage

4. Kirchhoff’s Laws

– Kirchhoff’s laws: principles governing the behavior of electrical circuits

– Kirchhoff’s voltage law (KVL): sum of voltages around any closed loop in a circuit is zero

– Kirchhoff’s current law (KCL): sum of currents entering a junction is equal to the sum of currents leaving the junction

– Applications of Kirchhoff’s laws in circuit analysis and troubleshooting

5. DC Circuits Analysis

– Analysis of series circuits: calculation of total resistance, current, and voltage drop across components

– Analysis of parallel circuits: calculation of equivalent resistance, total current, and voltage across components

– Voltage divider rule and current divider rule for series and parallel circuits

– Applications of DC circuits analysis in electrical engineering, electronics, and power distribution

6. Power and Energy in Electrical Circuits

– Electrical power: rate at which electrical energy is consumed or produced in a circuit (P = VI)

– Power dissipation in resistors: calculation of power using Ohm’s law and power formula

– Energy consumption and energy transfer in electrical circuits: calculation of energy using power and time

– Applications of power and energy calculations in electrical appliances, renewable energy systems, and power grids

7. RC Circuits and Time Constants

– RC circuits: circuits containing resistors and capacitors, commonly used in timing applications

– Charging and discharging of capacitors in RC circuits: time-dependent behavior governed by RC time constant (τ = RC)

– Analysis of RC circuits: determination of voltage across capacitors and current through resistors at different time intervals

– Applications of RC circuits in signal processing, filtering, and pulse generation

8. Magnetism and Electromagnetic Induction (Optional)

– Magnetic field: region of space around a magnet or current-carrying conductor where magnetic forces are experienced

– Electromagnetic induction: generation of electromotive force (emf) in a conductor due to a changing magnetic field

– Faraday’s law of electromagnetic induction: magnitude of induced emf proportional to the rate of change of magnetic flux

– Applications of electromagnetic induction in power generation, transformers, and electric motors

9. Advanced Topics (Optional)

– AC circuits analysis: impedance, phase angle, and power factor in AC circuits

– Three-phase power systems: generation, transmission, and distribution of electrical power using three-phase AC circuits

– Transmission line theory: analysis of electrical transmission lines for power transfer and signal propagation

– Power electronics: control and conversion of electrical power using semiconductor devices and switching circuits

Course Delivery:

The course will be delivered through a combination of lectures, laboratory experiments, demonstrations, and multimedia presentations. Real-world examples and practical applications will be integrated into the curriculum to illustrate the relevance of current electricity concepts. Computer simulations and visualization tools may also be used to enhance learning and comprehension.

Assessment:

Student learning will be assessed through quizzes, laboratory reports, homework assignments, midterm exams, and a final examination. Evaluation criteria will include understanding of current electricity concepts, proficiency in solving problems, and ability to apply principles to analyze real-world circuits. Regular feedback and opportunities for hands-on experience will be provided to support student learning and mastery of the material.

Prerequisites:

Students enrolling in this course should have a basic understanding of electric charges and fields, as well as algebra and basic calculus. Familiarity with fundamental concepts of physics, such as forces and energy, is recommended but not required. A strong willingness to engage in problem-solving and critical thinking is essential for success in this course.

By the end of Unit 3, students will have developed a solid understanding of current electricity and its applications in various fields of physics and engineering. They will be proficient in analyzing electrical circuits, interpreting circuit behaviors, and applying circuit analysis techniques to solve problems related to electric power, energy transfer, and signal processing.