Transcript power point to take notes on: Lecture 5

Introduction to Electrical & Computer Engineering
Inductors
Dr. Cynthia Furse
University of Utah
Dr. Cynthia Furse
University of Utah
1
Inductors
• What is Inductance ?
• How does it relate to magnetic field &
Current?
• Explain the effect of µ, N, S, l
• What does it do to a voltage and current?
2
All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press
Inductors
Passive element that stores energy in magnetic
field
Solenoid Wound Inductor
N S
L
l
2
Henries
Magnetic permeability
µ=µo µr
µo = 1.26 x 10(-6) H
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS
Press, Used with Permission by the Publisher
Current and Magnetic field
4
Wire Wound Inductor
http://www.murata.com/products/emicon_fun/2011/03/inductor_en14.html
5
Multilayer Inductor
http://www.murata.com/products/emicon_fun/2011/03/inductor_en14.html
6
Thin Film Inductor
http://www.murata.com/products/emicon_fun/2011/03/inductor_en14.html
7
Electrical Properties of Inductors
• Inductance – current, charge, voltage,
power, energy
• What happens at DC?
• Series and Parallel
8
All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press
Inductors
Passive element that stores energy in magnetic
field
Solenoid Wound Inductor
1 t
i   vt  dt  i t0 
L to
• At dc, inductor looks like
a short circuit
• Current through inductor
must be continuous (no
abrupt change)
N 2 A
L
l
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS
Press, Used with Permission by the Publisher
10
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indtra.html
Inductors: Current & B Field
Current = begins to flow and starts to create
magnetic field
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS
Press, Used with Permission by the Publisher
Inductors: Current & B Field
Current = begins to flow in and starts to create
magnetic field
At t=0, this acts like an OPEN circuit
Voltage is high, current is low
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS
Press, Used with Permission by the Publisher
Inductors: Current & B Field
When magnetic field is established, current flows
freely
At t=∞, this acts like a SHORTcircuit
Voltage is low, current is high
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS
Press, Used with Permission by the Publisher
What does an inductor do to the
current ?
14
What does an inductor do to the
current ?
Vs/R
66% at
t=L/R
t
15
What does an inductor do to the
voltage ?
Vs
36% at
t=L/R
t
16
What does an inductor do to a
voltage and current?
Voltage changes
Instantly
At ‘steady state’
Voltage =0
At ‘steady state’
Current is Vs/R
Current changes
slowly
• t=0: OPEN CIRCUIT
• t=∞: SHORT CIRCUIT
17
http://macao.communications.museum/eng
/exhibition/secondfloor/moreinfo/2_3_6_Re
sistanceInductance.html
18
Inductors in Series & Parallel
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How can we use Inductors?
•
•
•
•
•
Resonators (synthesizers)
Matching Impedances
AC Choke
Transformers
Inductive coupling
20
http://www.murata.com/products/emicon_fun/2011/03/inductor_en14.html
Inductive Coupling
http://www.ferroxtag.com/RFID/CP.LFHFUHF.htm
21
Inductive Coupling:
Electric Wave Buses (UofU)
22
Blackrock Microsystems
http://www.blackrockmicro.com/content.asp
x?id=60
23
Passive RFID
24
Transformers
25
Transformers
26
Low Pass filter
Noise Filter / Integrator
27
High Pass Filter
DC Block / Differentiator
28
White Canyon, American Fork
Dr. Cynthia Furse
University of Utah
Dr. Cynthia Furse
University of Utah
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