Transcript KEEP Kentucky Electronics Education Project

KEEP
Kentucky Electronics
Education Project
Dr. Janet Lumpp - Electrical and Computer Engineering
Dr. Kelly Bradley - Educational Policy Studies and Evaluation
University of Kentucky
July 2005
KEEP Objectives
 Educate teachers regarding
 Electronic assembly technologies
 Properties of electronic materials
 Develop curriculum materials
 Solicit industry partnerships
 Organize hands-on projects and
fieldtrips
 Encourage young students to
consider technical and engineering
careers
July 2005
KEEP Workshop
KEEP Background
 Classroom activities
 Teacher workshops
 Independent implementations
 West Jessamine High School
 The Lexington School
 Lafayette High School
 Girls in Science - students and teachers
 KSTA PD Session - November 2005
July 2005
KEEP Workshop
KET Partnership
CD-ROM
Coming Soon
 Studio session
 Filmed “cooking show” circuit steps - Dec’04
 Editing now
 SMC, Inc. - Electronic assembly process
 Filmed manufacturing equipment - June’05
 Editing now
 NAVSEA Crane - PCB fabrication
 Filming to be scheduled after renovation
July 2005
KEEP Workshop
Electricity to Electronics
 Electricity and Magnetism
 Principles and definitions
 Circuit elements, symbols
and diagrams
 Electronic Circuits
 Add semiconductor devices
 Physical size of components
 2D and 3D locations and
connections
July 2005
KEEP Workshop
Types of Components
 Through hole or Surface Mount
 Passive or Active
July 2005
KEEP Workshop
Printed Circuit Boards
 PCB = Printed Circuit Board
 Copper conductor
 Epoxy/Glass insulator
 Green coating = solder mask
 Single or double sided copper
 Single or multiple layers
 Through holes = vias
 Component leads
 Connect layers
 Plated with copper
July 2005
KEEP Workshop
How to Solder
 Soldering iron = heat source
 Heat copper ring and component lead
 Bring in solder wire
 Activate flux to clean oxides off of metal surfaces
 Solder alloy melts and wets clean metal surfaces
 Pull solder wire away from joint
 Remove soldering iron
 Coat soldering iron tip with solder to
prevent oxidation between uses
July 2005
KEEP Workshop
Project Steps
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Layout pattern drawn from schematic
Print layout on Press-N-Peel paper
Iron pattern on to clean copper PCB
Soak off paper backing, repair lines
Etch excess copper in sodium persulfate
Remove remaining toner (etch resist)
Drill through holes
Insert components
Hand solder
July 2005
KEEP Workshop
Implementation Options
 Purchase or borrow tools
 Purchase circuit project kits
 Solder only
 Drill and Solder
 Full process
 On-going PD Workshops
 Science, math, technology teachers
 Core team in one school or district
 Develop instructional units
July 2005
KEEP Workshop
Science Standards and KEEP
 SC-M-1.3.2 Heat energy moves in predictable
ways, flowing from warmer objects to cooler ones,
until both objects reach the same temperature.
 Soldering iron converts electrical energy to heat energy.
 Must make contact with cooler objects to transfer heat by
conduction.
 The temperature of the iron is greater than the melting
point of the solder.
 Solid-liquid-solid transformation at each solder joint.
July 2005
KEEP Workshop
Science Standards and KEEP
 SC-M-1.3.1 Energy is a property of many substances and
is associated with heat, light, electricity, and sound.
Energy is transferred in many ways.
 SC-M-1.3.5 Electrical circuits provide a means of
transferring electrical energy when heat, light, sound, and
chemical changes are produced.
 Flashing LED Circuit - heat, light, electricity, chemical to
electrical (battery) energy conversion
 Buzzer Circuit - heat, light, electricity, sound, chemical to
electrical (battery) energy conversion
July 2005
KEEP Workshop
Science Standards and KEEP
 SC-H-1.1.1 Matter is made of minute particles called
atoms, and atoms are composed of even smaller
components. … The electric force between the nucleus
and the electrons holds the atom together.
 SC-H-1.2.1 Atoms interact with each other by transferring
or sharing outermost electrons. These outer electrons
govern the chemical properties of the element.
 Electrons and chemical bonding determine which materials
are conductors, insulators and semiconductors.
 All types of materials are needed in microelectronics.
 Different materials must bond without contamination.
July 2005
KEEP Workshop
Science Standards and KEEP
 SC-H-1.3.1 Chemical reactions occur all around us and in
every cell in our bodies. These reactions may release or
consume energy. Rates of chemical reactions vary. Reaction
rates depend on concentration, temperature, and properties
of reactants. Catalysts speed up chemical reactions.
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Etching Copper - solution of sodium persulfate in water
Solution is heated to increase the reaction rate.
As copper is etched, the reaction rate slows (concentration).
Catalyst can be added to increase the reaction rate again.
July 2005
KEEP Workshop
Math Standards and KEEP
 MA-E-1.1.5 Multiple representations of numbers (e.g.,
drawings, manipulative, symbols)
 MA-M-1.1.6 Representation of numbers and operations in
a variety of equivalent forms using models, diagrams, and
symbols (e.g., number lines, 10 by 10 grids, rectangular
arrays, number sentences)
 Resistor color code - colors represent numbers 0 to 9
 Two digits and order of magnitude, 123 = 12 X 103
 Tolerance of  5% (gold) or 10% (silver)
July 2005
KEEP Workshop
Resistor Color Code
http://www.mechatronics.me.vt.edu/VT84Construction/resistorcodes.html
July 2005
KEEP Workshop
Science Standards and KEEP
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SC-H-3.5.5 Human beings live within the world’s ecosystems. Human activities
can deliberately or inadvertently alter the dynamics in ecosystems. These
activities can threaten current and future global stability and, if not addressed,
ecosystems can be irreversibly affected.
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Science in Personal and Social Perspectives -describe the individual’s roles
and responsibilities in the following areas: changes in populations, resources
and environments including ecological crises and environmental issues, natural
hazards, science and technology in society, and personal and societal issues
about risks and benefits.
 Electronics manufacturing uses tremendous amounts of metals, acids,
water, energy, etc.
 What are the safety issues for workers?
 What are the environmental issues?
 What are the economics of improving the manufacturing methods?
July 2005
KEEP Workshop
Math, Science and KEEP
 Science as Inquiry
 Science and Technology
 Science in Personal and
Social Perspective
 MA-E-1.1.4 Place value,
expanded form, number
magnitude (order, compare)
to 100,000,000, and decimals
through thousandths.
 Orders of magnitude in dimensions, memory, pixels, processor speed.
 Why is it that a new PC with 24 GB of RAM is not any bigger than an
old PC with 24 MB of RAM, a 1000 times increase in memory?
 Why is it that a 10 MB hard drive used to be the size of a shoe box and
now 40 GB fit in an iPod in your hand running on batteries?
 Why does the microprocessor in a new laptop PC run 5 times faster
than an old laptop, but the batteries last longer in the new laptop?
July 2005
KEEP Workshop
Math Standards and KEEP
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MA-H-2.1.1 Students will describe properties of and give examples of geometric
transformations and apply geometric transformations (translations, rotations,
reflections, dilations), with and without a coordinate plane, to both real-world
and mathematical situations.
MA-H-2.2.1 Students will perform transformations (reflections, translations,
rotations, dilations) on figures.
MA-H-2.2.2 Students will classify two-dimensional and three-dimensional
geometric figures according to their characteristics such as lengths of sides;
angle measures; and number of sides, faces, edges, and vertices. Students will
describe the intersection of a plane with a three-dimensional geometric figure.
 Identify components by describing the three dimensional shapes of the
packages and leads.
 Recognize components by their two dimensional projections as seen by
visual alignment systems. Sophisticated vision systems see color and
read labeling.
 XY Locations on a circuit board - placing components, dispensing dots
of adhesive, wirebond pads around a chip
July 2005
KEEP Workshop
Math Standards and KEEP
 MA-H-2.3.4 Students will understand how a change in one
or more dimensions of a geometric shape affects
perimeter, area, volume, or surface area.
 Area density = percentage of board area occupied by
components.
 Circuits are miniaturized by choosing smaller components
and reducing the spacing between objects.
 Use layout software to compare alternative designs and
calculate area density.
July 2005
KEEP Workshop
Math Standards and KEEP
 MA-H-4.1.1 Students will understand the concept of a function and
roles of independent and dependent variables.
 MA-H-4.1.4 Students will identify linear, quadratic, absolute value, and
exponential functions from graphs and equations.
 MA-H-4.1.5 Students will apply direct and inverse variation to both realworld and mathematical problems.
 MA-H-4.3.2 Students will understand how formulas, tables, graphs,
and equations of functions relate to each other.
 I-V (Current-Voltage) relationships for resistors, capacitors,
inductors
 Series and parallel combinations of resistors, capacitors,
inductors
 Current and voltage divider expressions for resistors
 555 timer formulas
July 2005
KEEP Workshop
I-V Relationships
 Resistors
 Ohm’s Law
 V=IR
 Capacitors
 ic(t) = dvc(t)/dt
 Inductors
 vL(t) = diL(t)/dt
July 2005
KEEP Workshop
Kirchoff’s Laws
 Kirchoff’s Voltage Law - KVL
 The sum of all voltages around a
closed loop is zero.
 S Vn = 0
 Kirchoff’s Current Law - KCL
 The sum of all currents entering
a node is zero.
 S In = 0
July 2005
KEEP Workshop
Series and Parallel
 Elements in series have the same current flowing
through them.
 Elements in parallel have the same voltage
across them.
 Series R, Series L, Parallel C
 Rs = S Rn
 Parallel R, Parallel L, Series C
 1/RP = S 1/Rn
 Two R in parallel RP = (R1R2)/(R1 + R2)
July 2005
KEEP Workshop
Current and Voltage Dividers
 Combine Ohm’s Law and
Kirchoff’s Laws to develop
short cut formulas
 Voltage divider
 v1 = v(R1/(R1+R2))
 Current divider
 i1 = i(R2/(R1+R2))
July 2005
KEEP Workshop
Capacitor Discharging
and Charging
 DC (battery) sources
 Capacitor is initially charged to a
voltage V0
 Discharging
 v(t) = V0e-t/t
 t = RC = time constant
 Charging from V0 to Vs,
 Vs = steady state
 v(t) = Vs +(V0-Vs) e-t/t
 If V0 = 0, v(t) = Vs(1 - e-t/t)
July 2005
KEEP Workshop