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Name : B. Damodaram
Designation : Lecturer
Branch : Electrical & Electronics Engineering
Institute : Govt. Polytechnic, Mahabubnagar
Year/Semester : I Year
Subject : Basic Electrical Engineering
Subject Code : EE105
Topic : Conducting Materials
Duration : 50 minutes
Sub Topic : High Resistivity Materials
Teaching Aids : PPT, Animation, Diagrams
Revised by : A.K. Srikanth, L/EEE, Q.Q.GPT, HYD
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In the previous class we have studied about
Recap
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• ACSR is a steel core surrounded by strands of Aluminium
• ACSR is having lower weight for longer spans
• ACSR conductors are used for over head transmission lines
• AAAC is made from Aluminium - Magnesium -
Silicon alloy
• AAAC are used for over head transmission lines
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• Understand the requirements of high resistivity
materials
On completion of this period , you would be
able to
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• Understand the applications of high resistivity
materials
Objectives
• Types of high resistivity materials
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What are the types of conducting materials used for
• High resistivity conducting materials
Ex : Tungsten, Nichrome etc.
• Filaments in bulbs
• Heating elements in heaters
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High Resistivity Materials
• Materials having low conductivity
• Used where large value of resistance is required
• High resistivity materials are mostly alloys of
different materials
• High resistivity materials are Manganin ,Platinum,
Nichrome , Tungsten etc
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Kettle Boilers Electrical Stove
Immersion
Heaters Immersion
Heaters
Immersion
Heaters
Immersion
Heaters
furnaces furnaces
Applications of High Resistivity Materials
• As heating elements in the following applications
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• As a filaments of electrical lamps
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High resistance filament (Tungsten )
Applications of High Resistivity Materials
Contd..
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• As rheostats
High resistance material ( Manganin )
Applications of High Resistivity Materials
Contd..
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• Low temperature coefficient of resistance
• High melting point
• High mechanical strength
• High ductility
• High malleability
Properties of
High Resistivity Materials
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• No brittleness
• Should dissipate more heat per unit volume
• Should not easily oxidize on heating
• Long life
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Properties of
High Resistivity Materials
Contd..
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Summary
• High resistivity materials should have high
resistance, high melting point and more heat dissipation
• High resistivity materials are used as a filaments in
lamps and as a heating elements in heaters etc.,
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In this period we have discussed about
• High resistivity materials are used in filaments of
lamps, heating elements in heaters etc.
• High resistivity materials are Manganin, constantan,
Nichrome, Tungsten, Platinum, Mercury and Carbon
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1. High resistivity materials should require
(a) Low resistance
(b) Low voltage drop
(c) High melting point
(d) Low power loss
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Quiz
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2. High resistivity material is_____________
(a) Copper
(c) Nichrome
(b) Aluminium
(d) Silver
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Nichrome
Quiz
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3. High resistivity materials should have
(a) High resistance
(b) High thermal conductivity
(c) High melting point
(d) All of the above
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Quiz
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4. Which of the following is high resistivity material
(a) Platinum
(c) Nichrome
(b) Carbon
(d) All of the above
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Quiz
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1. State the properties of high resistivity materials.
2. Write the applications of high resistivity materials.
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3. What is meant by high resistivity materials.
4. List the types of high resistivity materials.
Frequently Asked Questions
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In the next class we will discuss about
Next Class Topic
• Understand the Properties of Manganin
• Understand the Applications of Manganin.
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full potential... these are the
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