ELL100: INTRODUCTION TO ELECTRICAL ENG. Resistor, Inductor, and Capacitor Course Instructors: J.-B. Seo, S. Srirangarajan, S.-D. Roy, and S. Janardhanan Department of Electrical Engineering, IITD

SI (System International) units:

Derived Quantities:

Charge An electrical property of the atomic particles of which matter consists, measured in coulombs (C) - equal in magnitude to

Charge An electrical property of the atomic particles of which matter consists, measured in coulombs (C) - equal in magnitude to In 1 C of charges, The law of conservation of charges - neither be created nor destroyed, only transferred - The algebraic sum of the electric charges in a system does not change

Current The time rate of change of charge, measured in Ampere Direct current (dc) : a current that remains constant with time Alternating current (ac) : a current that varies sinusoidally with time

Voltage & Power An electric circuit - an interconnection of electric elements (battery, lamp, etc.) Voltage between two points a and b in an electric circuit - the energy (work) needed to move a unit charge from a to b Power is the time rate of expending or absorbing energy

Definitions (Voltage per meter)

Definitions velocity

Definitions Magnetic flux (Weber)

Electrical Power and Energy

Figure: Current and power Example 1 The “electron gun” of a cathode-ray tube provides a beam of high- velocity electrons. If the electrons are accelerated through a potential difference of 20,000 V over the distance of 4 cm (as shown in Figure), calculate the average field strength. Calculate the power supplied to a beam of 50 million billion electrons per second. Figure: Current and power

Example 1

Example 1

Resistance (Ohms Law)

Capacitance

Inductance

Figure: Current-voltage relations in a capacitor Example 2 A current varied as a function of time as shown in Figure. Predict and plot the voltage produced by this current flowing in an initially uncharged 1 µF capacitor. Figure: Current-voltage relations in a capacitor

Example 2

Circuit Diagram Convention I

Circuit Diagram Convention II

Circuit Diagram Convention III Branch - Path containing one or more elements that connects two nodes Node - Terminal common to two or more branches of a circuit Loop - Closed path progressing from node to node and returning to the starting node.

Circuit Elements I

Circuit Elements II

Circuit Elements II

Circuit Elements II

Energy Storage in Linear Elements I

Energy Storage in Linear Elements II

Energy dissipation in Linear elements

Continuity of stored energy

Example 3

Energy sources and Reversible transforms I

Energy sources and Reversible transforms I

Circuit Diagram Convention III