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Advanced Design Applications
Power and Energy
Teacher Resource
Learning Cycle 2
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
The BIG Idea

Big Idea:
Energy and Power are technologies
that are necessary to use in the
designed world. Understanding how
electric circuits operate will allow users
to manipulate and control the energy
and power.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Electronics Introduction
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Types of Components
Active
Passive
Batteries
Resistors
Transistors
Capacitors
Vacuum tubes
Inductors
Amplifiers
Amplifiers
Generators
Generators
Supply or control electric
energy within a circuit.
Do not introduce electric
energy into a circuit, but either
store or dissipate existing
electric energy.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Electric versus Electronic
What is the difference?
An electronic circuit contains at least one transistor or
tube.
Devices which contain electronic circuits (TVs,
radios, iPods) are electronic.
Electric motors are never electronic because they
do not contain transistors or tubes.
Most motor control circuits are electronic because
they contain transistors or tubes.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Basic Circuit Variables
Charge
Bipolar – electrical effects are described
in terms of positive and negative charges
Unit is the coulomb (C)
Charges exist in discrete quantities,
which are multiples of the electronic
charge (1.6022 x 10^-19 C)
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Basic Circuit Variables
Voltage
An electrical force created by the
separation of charge
Measured in volts (V)
Symbol: V
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Basic Circuit Variables
Current
An electric fluid that is created by the
motion of charge
Measured in Amps (A)
Symbol: I
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Basic Circuit Variables
Power
Energy per unit of time
Measured in watts (W)
Symbol: P
Algebraic sign for power:
If P>0, power is being delivered
If P<0, power is being extracted
© 2013 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Foundations of Technology
Analog versus Digital
ANALOG – gradually increases or
decreases
Variable voltage when potentiometer is
stopped between high and low
Continuous signal
DIGITAL – square waveform
Voltage is HIGH (on) or LOW (off)
Discrete signal
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Where are digital electronics
used?
Microcomputers –
complex ICs,
microprocessors
Calculators
Robots
Notebooks
(laptops)
Timepieces
(watches or
clocks)
Music equipment
Automobiles
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications

IC Test equipment –
Digital capacitance
meter
Frequency counters
Most modern
electronics
equipment contain
analog and digital
circuitry
Why use digital circuits?
Required when data
Must be stored
Used for calculations
Displayed as numbers or letters
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Advantages of Digital Systems
1.
Inexpensive ICs can be used with few external
components.
2.
Information can be stored for short periods of
time, or indefinitely.
3.
Data can be used for precise calculations.
4.
These systems can be designed more easily
using compatible digital logic families.
5.
These systems can be programmed and show
some manner of intelligence.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Limitations of Digital Systems
1.
Most real-world events are analog in nature.
2.
Analog processing is usually simpler and faster.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Resistors . . .
What is a resistor?
It uses the concept of resistance.
This is defined as the capacity of
materials to impede the flow of current (or
the flow of electric charge)
Measured in Ohms – Ω
Symbol: R
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Resistors
Resistors are noted by resistance…
There are many different sizes and shapes of
resistors. The larger the physical size of the
resistor, the larger the power rating.
Precision-type resistors consist of a thin wire
wrapped around a ceramic core and covered
with a ceramic coating.
Standard marking methods are used
Color codes are the basis
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
A Resistor
Retrieved from
http://www.cdxetextbook.com/electrical/princ/electronic/resistorratings.html
on August 4, 2014
Resistor Color Chart
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
How to Use the Color Chart for
Resistors
1.
Position the resistor so that the tolerance
band is on the right.
There is a large space between the tolerance band and
the other bands.
In some cases, there may not be a tolerance band.
You should still make sure that this side of the resistor is
on the right.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Using the Resistor Color Chart
2.
Identify the first band and look it up in the
resistor color code chart (1st BAND column).
Write down the number associated with that
color.
3.
Now read in order, from left to right, the second
color band. Look it up in the resistor color code
chart (2nd BAND column). Write down the
number associated with that color.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Using the Resistor Color Chart
continued
4.
Read the third resistor color band, which
corresponds to the 3rd BAND column in the
chart. Write down the value found.
5.
The fourth color band is the multiplier. Again,
look that color up in the resistor color coding
chart and multiply the value written so far with
the one from the resistor color chart in the
multiplier column.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Using the Resistor Color Chart
continued
6.
The last resistor color band corresponds to the
tolerance. Simply look up the color printed on
the resistor for the tolerance band in the
resistor color code chart and write it down.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Using the Resistor Color Chart
Special Notes
If the resistor has one more band past the
tolerance band it is a quality band.
Read the corresponding color number from the
1st BAND column. It is specified as the “%
Failure rate per 1000 hour.”
This is rated assuming full wattage being
applied to the resistors.
To improve the failure rates resistors are
typically required having twice the needed
wattage dissipation that the circuit they are
used in produces.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Using the Resistor Color Chart
Special Notes
In some cases, there may be four color
bands, including the tolerance band. In this
case, the third band is the multiplier band.
When the multiplier band is gold, the
resistor value is between 1 and 10 ohms.
Use a multiplication factor of 0.1 to the first
two digits.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Using the Resistor Color Chart
Special Notes
When the multiplier band is silver, the
resistor value is less than 1 ohm. Use a
multiplication factor of 0.01 to the first two
digits.
Resistors of 5, 10, and 20% tolerance are
typically made from carbon. These types
of resistors are basically used to limit
current flow in a circuit.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Let’s try an example . . .
We will use file LC2.3
Now let’s practice . . .
We will use file LC2.4
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Ohm’s Law
Used to calculate current flow, voltage, or
resistance (with the other two values known).
V=IR
Let’s try an example…
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Kirchhoff’s Current Law
The algebraic sum of currents entering and leaving
any point in a circuit must equal zero.
In other words:
No matter how many paths exist into and out of a
single point, all the current entering the point must
equal the current leaving the point.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Kirchhoff’s Voltage Law
The algebraic sum of the voltages around
any closed path is zero.
In other words:
The voltage drops around any closed loop
must equal the applied voltages.
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Resistors in Series
Series: when the circuit follows a single path
The series resistors can be simplified into one
resistor value for a closed loop.
They are simply added together.
Req = R1 + R2 + R3 + … + Rn
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Series Resistor Example
If R1 = 8 Ω, R2 = 10 Ω, and R3 = 14 Ω,
what is Req?
Draw a simplified circuit.
If a 12V battery is being used, what is the
current through each resistor?
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Resistors in Parallel
Parallel: when the circuit has several branches
Again, the parallel resistors can be simplified
into a single resistor value to simplify the circuit.
Req = 1 / (1/R1 + 1/R2 + 1/R3 …)
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Parallel Resistor Example
If R1 = 8 Ω, R2 = 8 Ω, and R3 = 4 Ω, what is Req?
Draw a simplified circuit.
If a 10V battery is being used, what is the total current
through the circuit?
What are the currents through each branch?
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
2 Resistors in Parallel
Using the relationship previously examined for
parallel resistors, a short formula can be
derived for 2 resistors in parallel.
1/Req = 1/R1 + 1/R2
Using fractional math, we simplify to:
1/Req = (R2 + R1)/R1R2
The last step in simplifying is reciprocating the
equation:
Req = R1R2/(R1 + R2)
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications
Power Equations
Now that we have examined current, voltage,
and resistance in detail, we can use a couple of
different equations to calculate power:
VI=P
P = V2/R
© 2014 International Technology and Engineering Educators Association
STEMCenter for Teaching and Learning™
Advanced Design Applications