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Circuit Analysis-1 Fall-2014 EE -1111 Instructor: Hafiz Zaheer Hussain Email: zaheer.hussain@ee.uol.edu.pk www.hafizzaheer.pbworks.com Department of Electrical Engineering The University of Lahore Lecture # 23 & 24 22/12/2014
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Content Introduction Capacitor Energy storage in capacitor Series and parallel Capacitors Inductor Energy storage in Inductor Series and parallel Inductors 22/12/2014
Content Introduction Capacitor Energy storage in capacitor Series and parallel Capacitors Inductor Energy storage in Inductor Series and parallel Inductors 22/12/2014
Introduction 22/12/2014
Content Capacitor Introduction Energy storage in capacitor Series and parallel Capacitors Inductor Energy storage in Inductor Series and parallel Inductors 22/12/2014
Capacitor 22/12/2014
Capacitance we define: Capacitance is the ratio of the charge on one plate of a capacitor to the voltage difference between the two plates, measured in Farad (F). Thus, 1F = 1 coulomb/volt 22/12/2014
Capacitance 22/12/2014
Capacitors are commercially available in different values and types. Commercially Available Capacitor Capacitors are commercially available in different values and types. Electrolytic Capacitors Ceramic Capacitors Chip Capacitors Polarity must be observed 22/12/2014
Fixed & Variable Capacitors Symbol 22/12/2014
Polar & Non-polar Capacitors 22/12/2014
Capacitance 22/12/2014
Current- Voltage Relationship of the Capacitor 22/12/2014
Current and Voltage Expression 22/12/2014
Capacitor Properties The capacitor has the following important properties: When the voltage across a capacitor is constant (not changing with time) the current through the capacitor: i = C dv/dt = 0 Thus, a capacitor is an open circuit to dc. If, however, a dc voltage is suddenly connected across a capacitor, the capacitor begins to charge (store energy). The voltage across a capacitor must be continuous, since a jump (a discontinuity) change in the voltage would require an infinite current, which is physically impossible. Thus, a capacitor resists an abrupt change in the voltage across it, Conversely The voltage across a capacitor cannot change instantaneously 22/12/2014
Capacitor Properties The capacitor has the following important properties: 3. The ideal capacitor does not dissipate energy. It takes power from the circuit when storing energy and returns previously stored energy when delivering power to the circuit. 4. A real, non-ideal, capacitor has a “leakage resistance” which is modeled as shown below. The leakage resistance may be as high as 100M, and can be neglected for most practical applications. Note: In this course we will always assume that the capacitors are ideal. 22/12/2014
Content Introduction Energy storage in capacitor Capacitor Series and parallel Capacitors Inductor Energy storage in Inductor Series and parallel Inductors 22/12/2014
Energy Storage 22/12/2014
Energy Storage 22/12/2014
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Content Introduction Series and parallel Capacitors Capacitor Energy storage in capacitor Series and parallel Capacitors Inductor Energy storage in Inductor Series and parallel Inductors 22/12/2014
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