Transcript Document

2014 AFA TEACHERS WORKSHOP
AIR FORCE ASSOCIATION MIAMI-HOMESTEAD CHAPTER and MIAMI-DADE COUNTY PUBIC
SCHOOLS
FEBRUARY 7, 2014 GEORGE T. BAKER AVIATION SCHOOL
Sponsors
Air Force Association Miami-Homestead Chapter #317
Mitchell Wolfson, Sr. Foundation Arthur Hertz, President
Embry Riddle Aeronautical University
Miami-Dade County Public Schools Division of Career and Technical Education
George T. Baker Aviation School Dr. Sean Gallagan, Principal
GEORGE T. BAKER AVIATION SCHOOL
Basic Electricity (Engineering)
Instructor:
Goal:
After successfully completing this block the learners will be able to demonstrate and explain the
basic fundamentals of Basic Electricity, as well as to pass the Final Writing Test.
Objectives: Learners will be able to:
A. Identify basic principles and application of electrical systems.
B. Describe components, symbols and circuits.
C. Explain basic terms as current, voltage, and resistance and use a multi-meter to
measure them.
D. Identify relationship between Voltage, Current and Resistance.
E. Explain the importance of safety procedures when using electrical systems and protectoral
devices.
F. Describe the use of Switches, Generators, Transformers, etc.
G. Describe the link between electricity and magnetism.
H. Solve problems involving the design, build and test of an electrical circuit using a relay switch
and also for a burglar alarm.
I. Interprets text, instructions, tables, diagrams.
J. Successfully pass the Final Writing Test.
Teaching and Learning Activities:
Day 09 - Knowledge to be learned this day will include:
Variable Resistor LED Dimmer “Problem Solving”
Activities: (1 hr. and 30 min.) (In the Lab. /Classroom)
Objective:
After a lecture on electrical circuits and the use of the multi-meter, the student will be able to
build and test a circuit from the Exploration kit with an 80% of accuracy.
Overview:
•
•
•
•
The teacher will assist, explain and guide the learner throughout the session.
The teacher will ask procedural questions to ensure the students understanding of subject.
Electrical circuits are present in many areas of our lives whether we see them or not.
In this activity you will use the Exploration Kit Manual to construct a “Variable Resistor LED
Dimmer” found on pages 24-25.
In this activity the student will:
• Follow procedure given in the Exploration Kit Manual on pages 24-25.
• Build and test an electrical circuit using a red LED, Potentiometer 50kΩ, Resistor 100Ω,
Battery, and Battery Snap.
• Further develop their Science, Engineering, Math and Technology (STEM) skills.
Assessment and Review:
• Answer activity questions found on page 25.
• Before handing in your work ensure that you have answered all the questions.
Assessment and Review:
• Answer activity questions found on page 25.
• Before handing in your work ensure that you have answered all the questions.
Home Learning:
• Using Exploration Kit Manual review Breadbording Tips (page 7), Resistor Color Code
(page 8-9), Ohms Law for DC Circuits (page 53) and Resistance Formulas (page 54).
Closure:
• Teacher will ensure that the Technology Laboratory/Classroom is properly organized and
ready for the following class. She/he will also remind the learner on how to apply the daily
learning to his/her home learning.
Standards:
09.0 Demonstrate an understanding of engineering design.
10.0 Demonstrate an understanding of the role of troubleshooting, research and
Development, invention and innovation, and experimentation in problem solving.
12.0 Demonstrate the abilities to use and maintain technological products and systems.
17.0 Demonstrate safe and appropriate use of tools and machines in aerospace technologies.
21.0 Demonstrate an understanding of electrical, mechanical, fluid, and pneumatic systems
that could be used on/in aviation/aerospace environments.
Steps to obtain the Sunshine State Standards:
1.
2.
3.
4.
5.
6.
http://www.fldoe.org/bii/curriculum/sss/
Next Generation Sunshine State Standards.
Career and Adult Education.
Career and Technical Education Programs.
2013-14 Science, Technology, Engineering & Math (STEM) Curriculum Frameworks.
Engineering & Technology Education STEM Programs - Supervisor: Richard "Ted" Norman ,
850-245-9015.
7. Florida Department of Education.
8. Curriculum Framework.
9. Program Title: Aerospace Technologies.
Ohm’s Law
Tanθ = ct = V/I = R
Summary = Description=Blue line
is ohmic, Red line is non-ohmic.
Say a filament lamp over a range
of p.d's Yellow is a semiconductor.
V→ Potential difference on the
ends of a conductor (work done
by the electric field per unit of
charge.)
I → Intensity of the electric
current (charge per unit of time
that pass throw the section) area.
V and I are only related by Ohm’s
Law
R = V/I => (volt) / (amp) = (Ω)
R = ρ L/A => ρ = R A/L => (Ω)
(m²)/(m) => Ω m
Series circuits
Current
In a series circuit the current is the same for all elements.
Resistors R = ρ L/A => ρ = R A/ L
The total resistance of resistors in series is equal to the sum of their individual resistances:
Potential Difference or the Potential Drop (Voltage)
In a series circuit the voltage is the sum for all elements.
Vtotal = V1 +V2 + V3 +… + Vn
Parallel circuits
Potential Difference or the Potential Drop (Voltage)
In a parallel circuit the voltage is the same for all elements.
Resistors
The current in each individual resistor is found by Ohm's law. Factoring out the voltage gives
To find the total resistance of all components, add the reciprocals of the resistances of each
component and take the reciprocal of the sum. Total resistance will always be less than the
value of the smallest resistance:
For only two resistors, the unreciprocated expression is reasonably simple:
This sometimes goes by the mnemonic "product over sum".
For N equal resistors in parallel, the reciprocal sum expression simplifies to:
and therefore to:
Current
In a parallel circuit the current is the sum for all elements. Itotal = I1 + I2 + I3 + … + In
Series & Parallel circuits
If
R1 = 2Ω
R2 = 3Ω
R3 = 6Ω
R4 = 4Ω
1/R23 = 1/R2 +1/R3 =
(R3 +R2) / R2R3 =>
R23 = R2R3 / (R3+R2)
= 3ΩX6Ω / (6Ω+3Ω) =
18Ω / 9Ω = 2Ω
Total resistance in
parallel will always be
less than the value of
the smallest
resistance
Total resistance in series will be:
R1 + R23 + R4 = 2Ω + 2Ω + 4Ω = 8Ω
Summary
Multi-meter
Current (Amp)
The instrument is connected in Series or in line in the
circuit.
Difference of Potential or Voltage (volt) and Resistance
(ohm) (Ω)
The instrument is connected in Parallel or across in the
circuit.
Electric Power (P) (Work by unit of time that the electric field does.)
P = VI => (Volt) (Amp) = (Joule/ charge) (charge/ sec) = Joules/sec = Watt
Work = (P) (Time) = (J/sec) (sec) = Joule
The “FPL” charge $ 0.11 by kW h of work
1 kW h = 1000 (Joule/sec) (3600 sec) = 3.6 x10ⁿ Joule; n = 6
1kW h = 3.6 MJ
Example of some of the consumers that you have at home.
Oven ~ 1 kW
Air conditional ~ 3 kW
Dryer ~ 6kW
Refrigerator ~ 0.28 kW
TV ~ 0.15 kW
Water Heater ~ 8 kW;
If your water heater works during 10 hours / day you consume 8x10 = 80 kW h ; Equivalent to
80 x 0.11 = $8.80
Importance of Battery Power in
Aeronautics
• Aircraft Batteries needs to be checked for total
charge including each battery cell
• Pilots are always aware of battery life at all
times