The Basics of Electrical, Electronics and Communication Engineering For Students

Book for students

This is an introductory level text book in electrical, electronics and communication Engineering. It is prepared as per the syllabus for first year B Tech in Calicut University. The resources used were many internationally reputed text books, suggestions from experienced faculty members and students from electrical science branches of engineering in various engineering institutions.

This book intended also for the students in non-electrical science branches.

Single Phase AC Circuits

1. AC Fundamentals

An alternating voltage is any voltage that varies both in magnitude and polarity with respect to time. Similarly an alternating current is any current that varies both in magnitude and direction with respect to time.

Alternating current systems have many advantages compared to direct current systems. Alternating currents can be easily generated, transmitted and utilized as compared to direct current systems.

2. Generation of sinusoidal emf

A sinusoidal voltage can be generated either by rotating a coil in a stationary magnetic field or by rotating a magnetic field within a stationary coil.

where E_m and I_m are peak values of induced emf and current respectively and ω is the angular velocity of the coil given by:

ω = 2πf

where f is the frequency in Hz.

From the expressions of emf and current, it is clear that instantaneous values of emf and current vary as the sine functions of angle θ. So they are known as sinusoidal voltage and current.