Dept of Electrical & Electronics

Ganesh Kudva Dept. of Electrical & Electronics Engg.

Dept of Electrical & Electronics Required: Scientific Calculator Casio- fx-991ES Casio- fx-991MS

Dept of Electrical & Electronics We will learn here…  Classify electrical circuit elements  Active & Passive  Linear & Non linear  Unilateral & Bilateral  Lumped & Distributed  Ideal & Practical Active Elements  Source Transformation

Dept of Electrical & Electronics Electric Circuit Definition : An interconnection of simple electrical devices with at least one closed path in which current may flow

Dept of Electrical & Electronics Classification of Circuit Elements  Active & Passive Elements  Active Elements (Source): Voltage & Current Sources  Passive Elements (Sink): Resistor, Inductor & Capacitor  Linear & Non-linear Elements  Linear (Satisfies Superposition): Resistor, Inductor, Capacitor  Nonlinear: LDR (Light Dependent Resistor), Thermistor  Unilateral & Bilateral Elements  Unilateral (Current Flow in one direction): Diode, Transistor  Bilateral: Resistor, Inductor, Capacitor*  Lumped & Distributed Discuss only lumped linear bilateral circuit elements.

Dept of Electrical & Electronics Passive Elements  Energy Consuming Elements:  Resistor (R): RI 2  Energy Storing Elements  Inductor (L): Stores Energy in its Magnetic Field [0.5LI 2 ]  Capacitor (C): Stores Energy in its Electrical Field [0.5CV 2 ]

Dept of Electrical & Electronics Types of Active Elements Ideal Voltage Source:  Maintains constant voltage irrespective of connected load.  Internal resistance, R s = 0

Dept of Electrical & Electronics Types of Active Elements contd… Ideal Current Source:  Maintains constant current irrespective of the load connected.  Internal resistance, R s = ∞

Dept of Electrical & Electronics Practical Sources V-I Characteristics of battery

Dept of Electrical & Electronics Practical Sources contd…

Dept of Electrical & Electronics Practical Source Transformation  Conversion of Practical Voltage source to Current source & vice versa  The terminal characteristics of both the sources are same V s R a b I s R + - a b

Dept of Electrical & Electronics Example 1 Convert a voltage source of 100 V having an internal resistance of 5 Ω to its equivalent current source. Draw the circuit representation of both forms of sources a b + - a b V S = 100 V R S = 5 Ω I P = 20 A R P = 5 Ω

Dept of Electrical & Electronics Example 2 Find the power dissipated in 2 Ω resistor Ans: P = 12.5 W

Dept of Electrical & Electronics Example 3 Find the power dissipated in 15 Ω resistor using source transformation Ans: P 15Ω = W

Dept of Electrical & Electronics Summary We started with  How a typical electric circuit looks like Then looked into  Different types of circuit elements & their classifications  Ideal & practical sources Finally concluded with  How to transform practical voltage & current sources