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Basic Electrical Circuits
An Online Course

Dr. Nagendra Krishnapura , IIT Madras

Electrical circuits are everywhere, tiny ones in integrated circuits in mobile phones and music players, to giant ones that carry power to our homes. This course deals with basic elements of electrical circuits (R, L, C, M, ideal opamp) and analysis of circuits containing these elements. Systematic methods for analyzing large circuits, and tools for analyzing circuits with memory elements and time varying inputs will be discussed.
Course Duration
January 22 – April 30, 2013

Course Timings
Tuesdays and Thursdays, 4 – 5.30 pm IST


No Lecture on Tuesday (January 29)
Next Lecture will be on Thursday (January 31)

About The Course
The course begins with an introduction to basic linear elements used in electrical circuits. Mesh and node analysis for systematic analysis of large circuits will be studied. Fundamental circuit theorems and their use in analysis will be discussed. Two port parameters used for abstracting out the behaviour of complex circuits will be described. The notion of negative feedback, and the opamp as an element for implementing negative feedback circuits will be discussed. Differential equations are introduced as tools for analyzing circuits with memory. Sinusoidal steady state analysis for simple analysis of such circuits will be studied. The concepts of power and energy in circuits will be discussed. Rudiments of three-phase circuits and their analysis will be studied.

View Class Schedule, Contents and recorded lectures:



Lecture Title



Introduction to the course;  Current and Voltage; Kirchhoff's Current and Voltage laws



No lecture



Electrical circuit elements:  Voltage and current sources; R, C, L, M



Elements in series and parallel; Superposition in linear circuits



No lecture



Controlled sources; Energy and power in elements; Energy in a mutual inductor and constraint on mutual inductance



Nodal analysis of a network with conductances and current sources; Setting up the equations; Conductance matrix; Superposition



Nodal analysis with voltage sources and controlled sources; Modified nodal analysis



Modified nodal analysis with controlled sources; Loop analysis



Loop analysis with link currents as variables; Loop analysis for planar circuits(Mesh analysis) with mesh currents as variables



Substitution theorem; Thevenin's theorem



Thevenin's theorem; Norton's theorem; Pushing a voltage source through a node; Splitting a current source; Tellegen's theorem



Tellegen's theorem; Reciprocity theorem



Compensation theorem; Maximum power transfer theorem; Circuits with nonlinear components



Two port parameters



Negative feedback



Opamp for realizing negative feedback circuits; Determining opamp signs for negative feedback



Determining opamp signs for negative feedback; Circuits using opamps;  Opamp amplifiers;



RC circuit natural response; First order differential equation



Step response of RC circuits; Response of a first order circuit to exp(st)



Sinusoidal steady response of RC circuits; RL circuits



Step response of RC/RL circuits



No lecture (Ugadi)



Series RLC circuit; Second order differential equation; Natural response



Second order system natural response and step response; AC signal measures; Sinusoidal steady state analysis



Sinusoidal steady state analysis; Phasors



Sinusoidal steady state response of first order(RC) and second order(series RLC) circuits;  Series and parallel RLC circuits;



Complex power, Apparent power, Active and Reactive power, Power factor, Power factor correction; Conjugate matching for maximum power transfer



Coupled inductors; Ideal transformer



Three phase circuits; Star to Delta transformation; Real and reactive power with a balanced three phase load



Symmetrical component representation of unbalanced three phase components; Power measurement;  Two wattmeter method for three phase power measurement;



Extra class-if necessary

About the Instructor
Nagendra Krishnapura
Associate Professor
Dept. of Electrical Engg.
IIT Madras, Chennai 600036
http://www.ee.iitm.ac.in/~nagendra .
Nagendra Krishnapura is an associate professor in the VLSI group of the department of Electrical Engineering of the Indian Institute of Technology, Madras. He works in the area of analog and mixed signal circuits and signal processing. He graduated with a Ph.D. from Columbia University, New York in Oct. 2000. He worked at the Columbia Integrated Systems Laboratory under the guidance of Prof. Yannis Tsividis in the area of nonlinear analog signal processing for low power integrated circuits. He obtained a B. Tech. degree in electronics and communications engineering from the Indian Institute of Technology, Madras, in 1996. Between 2000 and 2005, he worked as a senior design engineer at Celight, Inc. and Multilink (later Vitesse Semiconductor), where he designed integrated circuits for high speed communications. From 2003 to 2005, he was an Adjunct Assistant Professor and taught courses on Analog Circuit Design at Columbia University.
Recommended Background / Prerequisites
  • Algebra, trigonometry, complex numbers, calculus, basic notions of charge, current, and potential at the CBSE 12th standard level.
Suggested Readings
  • Hayt, Kemmerly, and Durbin, Engineering Circuit Analysis, 7th Edition, McGraw Hill 2006.
1. What is the format/structure of this course?

This will be a semester-long course with the syllabus described above. There will be two live online lectures every week. Every lecture will be for about an hour and will be accompanied by quiz questions for assessing level of immediate comprehension.

At the end of a set of lectures, there will be an assignment on the topics covered. Approximately there will be one assignment covering every four lectures.

Mid-semester exam: Week of March 11-15, 2013

End semester (final) exam: April 29, 2013 or April 30, 2013

2. How do I access this course material? Are there any system requirements?

The live lectures will be delivered on Adobe Connect™. To follow the lecture live, you will need Internet access and point your browser to the URL to be announced soon in the NPTEL website.  The same lecture will be recorded along with the quiz questions/answers and made available for later viewing through NPTEL website and YouTube.

3. Can students ask questions online and/or contact the instructor offline?

There will be an online discussion forum in which students can ask and answer questions. Teaching assistants will be moderating the forum.

Limited synchronous interactions through Adobe Connect™ are possible during the live lectures as permitted by the instructor.

4. Are there any textbooks required to be purchased?

The recommended text will be a very useful supplement for the course, though it is strictly not required at any point.

5. What type of certificate will I get for completing this course?

Online students can get a participation certificate upon request from NPTEL. IIT Madras will not be directly involved in this process.

College students: please see the registration information below for more details on participation and certification with the involvement of your college.


Registration for online students (individuals)

If you would like to participate in this course online, Registration Closed. We will contact you with any course-specific information.

Registration procedure for college participation

We welcome colleges and universities to partner with NPTEL in the delivery of this online course. To initiate this process, the college/university/department head should write to nptel@iitm.ac.in. In this email, a faculty member of the college/university should be identified as the mentor for this course, and contact details (including phone, email) of the mentor should be provided. The mentor’s role is crucial for the success of the course, and this includes the following:

(1) Proctoring the viewing of the online lecture at the college (the lecture could be projected onto a large screen, if needed)

(2) Enabling interaction through Video Conferencing

(3) Moderating and conducting the quiz during the lecture

(4) Grading the assignments with the help of a key given by the instructor

(5) Conducting the mid-semester and end-semester exam

(6) Grading the mid-semester and end-semester exam with a key given by the instructor.

NPTEL will enter into an MoU with the interested colleges/universities to enable the smooth conduct of the online course. We encourage colleges/universities to provide course credit to students for this online course, wherever possible. If course credit is not possible, a joint grade card/certificate may be issued by the college/university along with NPTEL. The role of IIT Madras in the certification process will be clarified shortly after identifying a suitable mechanism through its Centre for Continuing Education. If you have any questions or concerns about this process, please write to nptel@iitm.ac.in in or visit NPTEL site periodically for updates.