Chapter 13
Transformer Applications
Chapter Objectives:
 Understand magnetically coupled circuits.
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Learn the concept of mutual inductance.
Be able to determine energy in a coupled circuit.
Learn how to analyze circuits involving linear and ideal transformers.
Be familiar with ideal autotransformers.
Learn how to analyze circuits involving three-phase transformers.
Be able to use PSpice to analyze magnetically coupled circuits.
Apply what is learnt to transformer as an isolation device and power
distribution
Huseyin Bilgekul
Eeng224 Circuit Theory II
Department of Electrical and Electronic Engineering
Eastern Mediterranean University
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Different Transformers
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LVDT Transformer:
The linear variable differential transformer (LVDT) is a sensor that can reveal displacement
using transformer effects.
A constant low-level ac signal is applied to the primary.
Voltage level induced in the secondary is based on core position, which is moved by some
external force. Position of the core can be related to the secondary voltage.
LVDT transformer: (a)
construction; (b) maximum
displacement; (c) minimum
displacement; (d) graph of
induced voltage versus
displacement.
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Three phase transformer connections
 A Y-Y three phase transformer connection.
 A Δ-Δ three phase transformer connection.
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Transformer for Power Supply Application
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Fluorescent Lamp
(a) general appearance
(b) internal view with ballast.
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Fluorescent Lamp
(a) Schematic of single-bulb
fluorescent lamp; (b) starter;
(c) internal view of ballast
transformer.
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Electrical Isolation
 Electrical ISOLATION exists between two devices when there is no physical
connection between them. A transformer provides AC isolation in a rectifier circuit
A transformer providing AC isolation in a rectifier circuit.
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DC Isolation
 A transformer providing DC isolation between two amplifier stages
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High Voltage Isolation
 A transformer providing isolation between power lines and the voltmeter
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Impedance Matching
 A transformer used as a IMPEDANCE MATCHING device
A transformer is used to
match the load resistance to
the source resistance to
provide Maximum Power
Transfer to the load.
 A transformer matching the speaker to the amplifier.
A transformer is used to
match the loudspeaker to
the output impedance of
the amplifier.
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Impedance Matching
Impedance Matching for public address system
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Impedance Matching Transformer for TV Antenna
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Power Distribution
 A typical power distribution system
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