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222/12/2014
Circuit Analysis-1 Fall-2014EE -1111
Instructor: Hafiz Zaheer HussainEmail: [email protected]
www.hafizzaheer.pbworks.com
Department of Electrical EngineeringThe University of Lahore
Lecture # 23 & 24
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Content
Introduction
Capacitor
Energy storage in capacitor
Series and parallel Capacitors
Inductor
Energy storage in Inductor
Series and parallel Inductors22/12/2014
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Content
Introduction
Capacitor
Energy storage in capacitor
Series and parallel Capacitors
Inductor
Energy storage in Inductor
Series and parallel Inductors22/12/2014
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Introduction
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Content
Introduction
Capacitor
Energy storage in capacitor
Series and parallel Capacitors
Inductor
Energy storage in Inductor
Series and parallel Inductors22/12/2014
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Capacitor
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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,
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Capacitance
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Capacitors are commercially available in different values and types.
Commercially Available Capacitor
Electrolytic Capacitors
Polarity must be observed
Ceramic Capacitors Chip Capacitors
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Fixed & Variable Capacitors
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Symbol
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Polar & Non-polar Capacitors
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Capacitance
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Current- Voltage Relationship of the Capacitor
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Current and Voltage Expression
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Capacitor Properties
The capacitor has the following important properties:
1. 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).
2. 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 abruptchange in the voltage across it, Conversely
The voltage across a capacitor cannot change instantaneously
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Capacitor 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.
The capacitor has the following important properties:
C
R S
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Content
Introduction
Capacitor
Energy storage in capacitor
Series and parallel Capacitors
Inductor
Energy storage in Inductor
Series and parallel Inductors22/12/2014
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Energy Storage
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Energy Storage
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Content
Introduction
Capacitor
Energy storage in capacitor
Series and parallel Capacitors
Inductor
Energy storage in Inductor
Series and parallel Inductors22/12/2014
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