Lesson Plan
Course Title: Construction Technology
Session Title: Basic Electrical Theory Understanding Ohm’s Law
Performance Objective:
Upon completion of this assignment, the student will be able to explain the units of
measurement that are used to measure the properties of electricity.
Specific Objectives:





Define Ohm’s Law and give its formula.
Explain how voltage, current, and resistance are related to each other.
Calculate an unknown value using the formula for Ohm’s Law.
Select the proper Ohm’s Law formula from Chart.
Discuss different types of electrical circuits.
Preparation
TEKS Correlations:
This lesson, as published, correlates to the following TEKS. Any changes/alterations to
the activities may result in the elimination of any or all of the TEKS listed.
130.55. Advanced Building Maintenance Technology
(6) Students will demonstrate knowledge of how to properly select, inspect, use,
and maintain common electrical test equipment and:
(a) explain the operation of various test equipment such as ammeter, voltmeter,
ohmmeter, volt-ohm-multimeter, wattmeter, megohmmeter, frequency meter,
power factor meter, continuity tester, voltage tester, recording instruments, and
cable-length meters;
(b) explain how to read and convert from one scale to another using test
equipment;
(c) explain the importance of proper meter polarity;
(d) define frequency and explain the use of a frequency meter; and
(e) explain the differences between digital and analog meters.
§130.368. Electronics
(a) Recommended for students in grades 10-12.
(c) Knowledge and skills. Students will demonstrate knowledge of:
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1
…Employment and career opportunities, including certifications, teamwork, health
and safety, ethics, diversity in the workplace, discriminatory practices,
written/oral communication and job shadowing, mentoring and apprenticeship;
…Teamwork;
…Project management;
…Work safety, including the Occupational Safety and Health Administration
regulations, hazardous material/waste disposal, equipment maintenance,
tool/material storage and the implications of improper maintenance;
…Project-based assessments, including Ohm’s law, Kirchoff’s laws and power
laws, magnetism, induction, the fundamentals of electronics theory, electricalelectronic troubleshooting and voltage regulation;
…Work situations, including being able to measure/calculate resistance, current,
voltage and power in series/parallel/complex circuits, generators, electric
motors, transformers, analog/digital circuits and optoelectronics;
…Engineering design methodologies, ideations, critical thinking, the use of an
engineering notebook for design and final projects;
…The use of tools, equipment and materials, such as laboratory equipment,
precision measuring instruments, oscilloscopes and software;
…Design processes and techniques like interpreting industry standard circuit
schematics, quality control, product improvement, meeting industry standards,
the patenting process, designing components and new technologies;
…Building a prototype, including planning, implementation and presentation.
Interdisciplinary Correlations:
English:
 110.xx(6) – Reading/word identification/vocabulary development
(A) expand vocabulary development through wide reading, listening, and discussing;
110.xx(6) - Vocabulary Development
 110.xx(6)(A)
...expand vocabulary through...listening and discussing
 110.xx(6)(B)
...rely on context to determine meanings of words...
Algebra I
 111.32(a)(4)
…relationship between equations and functions. Equations arise as a way of asking
and answering questions involving functional relationships. Students work in many
situations to set up equations and use a variety of methods to solve these equations.
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2
Instructor/Trainer
References:
1. Delmar’s Standard Textbook of Electricity.
2. Basics Of Electricity.
3. NCCER Wheels of Learning (Electrical).
4. MAVCC Basic Wiring.
5. http://www.the12volt.com/ohm/page2.asp
6. http://www.qsl.net/dx5apo/ohms_law.htm
7. http://texastechnology.com/Curriculum/Tech_Ed_Course/High_School
8. http://www.anderson-bolds.com/ (Ohm’s Law Calculator).
9. http://www.nace.org/nace/index.asp
10. Ohm's Law—NACE Cathodic Protection Program.
Instructional Aids:
1.
2.
3.
4.
Ohm’s Law PowerPoint Presentation.
Ohm’s Law PowerPoint Presentation Ohm’s Law Pie Chart.
Ohm’s Law PowerPoint Presentation Ohm’s Law Exam.
Ohm’s Law PowerPoint Presentation Ohm’s Law Exam Key.
Materials Needed:
1. Pencil and Paper.
2. Ohm’s Law Chart.
Equipment Needed:
1. Computer and Projector.
2. Calculator.
Learner
1. Students should be familiar with the operation of a calculator.
2. Students should also be familiar with basic math numbers and functions.
3. Students should have a working knowledge multiplying and dividing numbers
such as: frictions and decimals.
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Introduction
Introduction (LSI Quadrant I):
 ASK: How does electricity works, and why is it important for electricians to
understand how components voltage, current, resistance, and power of Ohm’s
Law interact with each other.

SAY: The relationship between voltage, current, and resistance in an electrical
circuit is fundamental to the operation of any circuit or device. Ohm’s Law
defines the relationship between power, voltage, current and resistance. These
are the very basic electrical units we work with. The principles apply to
alternating current (ac), direct current (dc) or radio frequency (rf).
Outline
Outline (LSI Quadrant II):
Introduction to Ohm’s Law
Instructor can use powerpoint presentation to aid lesson delivery
a Define Ohm’s Law
b. Define the components of Ohm’s Law
1. Electromotive Force
2. Intensity
3. Resistance
4. Power
c. Explain how each component interact with the others
d. Demonstrate by mathematical calculations the relationship between
each component.
Application
Guided Practice (LSI Quadrant III):
 Teacher uses a visual demonstration to show the effect of each component in
relationship to the other.
 Teacher supervises students with simulations of electrical demonstration.
 Teacher illustrates mathematical computations of electrical circuit.
Independent Practice (LSI Quadrant III):


Students are assign problems to reinforce mathematical concepts of electrical
circuitry.
Students may use calculators to aid in solving math problems.
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Summary
Review (LSI Quadrants I and IV):
Check for understanding: (Q & A)


Q: Name the three major components of Electrical Theory (Ohm’s Law).
A: They are Electromotive Force, Current, and Resistance.


Q: What are the unit of measurements for each component.
A: The measurements are for electromotive force > volts, current > amps,
and resistance > ohms.
Evaluation
Informal Assessment (LSI Quadrant III):
Students are presented with problem solving scenarios to ensure understanding
of lesson objectives.
Formal Assessment (LSI Quadrant III, IV):
Use Ohm’s Law Basic Concept Exam and Ohm’s Law Basic Concept Exam Key.
Use Electrical Circuits Vocabulary and Word Bank Quiz and Use Electrical
Circuits Vocabulary and Word Bank Quiz Key.
Extension/Enrichment (LSI Quadrant IV):
Students can participate in Lab experiment which demonstrates the correlation
between actual circuit readings and math computations.
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5
Basic Electrical Theory:
Understanding Ohm’ Law
Introduction



What is Ohm’s Law?
Why is ohms law important?
The Electrical Components of Ohm’s Law
1. Electromotive Force
2. Current
3. Resistance
4. Power
 Ohm’s Law Formulas
 Using The Ohm’s Law Chart to calculate electrical circuits.







Terms to Remember
The Source can be any source of electrical energy. In practice, there are three
general possibilities: it can be a battery, an electrical generator, or some sort of
electronic power supply.
The Load is any device or circuit powered by electricity. It can be as simple as a
light bulb or as complex as a modern high-speed computer.
(Path) a wire or pathway which will allow electron to flow throughout a circuit.
Electricity can be described as the flow of charged particles. If the particles
accumulate on an object, we term this static electricity.
(Direct Current) An electrical current that travels in one direction and used within
the computer's electronic circuits.
(Alternating Current) The common form of electricity from power plant to
home/office. Its direction is reversed 60 times per second.
Circuit is a conducting path for electrons.
What is Ohm’s Law?
Ohm's Law states that, at constant temperature, the electric current flowing in a
conducting material is directly proportional to the applied voltage, and inversely
proportional to the Resistance.
Why is Ohms Law important?
Ohm’s Law is the relationship between power, voltage, current and resistance. These
are the very basic electrical units we work with. The principles apply to alternating
current (ac), direct current (dc), or radio frequency (rf) .
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The Electrical Components of Ohm’s Law
Ohm’s Law Formulas
This is Ohm's law, where E = Volts;
I = current in amperes and R =
resistance in ohms.
Ohm’s Law expresses the relationship between the current (I), the voltage (E), and the
resistance (R) in a circuit. Ohm’s Law can be expressed in three different ways, and can
be applied to the entire circuit or to any part of a circuit. When any two factors are
known, the third unknown factor can be calculated from Ohm’s Law.
Characteristics Of Ohm’s Law
Finding Voltage
Ohm’s Law Formula for Finding Voltage
(E)
(I)
(R)
Voltage = Current x Resistance
To find Voltage, multiply the Current times the Resistance.
E=I x R
Using the Magic Circle
Cover the E to see the mathematical relationship between Voltage and Current
Finding Current
Ohm’s Law Formula for Finding Current
(I)
(E)
Current= Voltage
————
(R)
Resistance
To find Current, divide the Voltage by the Resistance.
E
I=—
R
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Using the Magic Circle
Cover the I to see the mathematical relationship between Voltage and Resistance
Finding Resistance
Ohm’s Law Formula for Finding Resistance
(R) (E)
Resistance= Voltage
———
(I)
Current
To find Resistance, divide the Voltage by the Current
E
R=—
I
Using the Magic Circle
Cover the R to see the mathematical relationship between Voltage and Current Ohm's
Law is a very simple and useful tool for analyzing electric circuits. It is used extensively
in the study of electricity and electronics. Remember When any two factors are known,
the third unknown factor can be calculated from Ohm’s Law.
Ohm's Law is a very simple and useful tool for analyzing electric circuits. It is used
extensively in the study of electricity and electronics. Remember When any two factors
are known, the third unknown factor can be calculated from Ohm’s Law.
REVIEW:
 Voltage measured in volts, symbolized by the letters "E" or "V".
 Current measured in amps, symbolized by the letter "I".
 Resistance measured in ohms, symbolized by the letter "R".
 Ohm's Law: E = IR ; I = E/R ; R = E/I
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Ohm's Law
Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One
ohm is the resistance value through which one volt will maintain a current of one ampere.
• Ohm's
• Ohm's
Law Pie Chart
Law Calculators
( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from
points of high voltage to points of low voltage on the surface of a conductor. Current is measured in (A)
amperes or amps.
( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or
pressure behind current flow through a circuit, and is measured in (V) volts.
( R ) Resistance determines how much current will flow through a component. Resistors are used to
control voltage and current levels. A very high resistance allows a small amount of current to flow. A very
low resistance allows a large amount of current to flow. Resistance is measured in ohms.
( P ) Power is the amount of current times the voltage level at a given point measured in wattage or
watts.
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Calculate for Resistance (R)
R=P/I
2
Power
Current
Resistance
clear
Watts
Amps
Ohms
Voltage
Current
Resistance
R=E/I
clear
Volts
Amps
Ohms
2
R=E /P
Voltage
Power
Resistance
clear
Volts
Watts
Ohms
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Calculate for Voltage (E)
E=IxR
Current
Resistance
Voltage
clear
Amps
Ohms
Volts
E=P/I
Power
Current
Voltage
clear
Watts
Amps
Volts
E = Square Root of (P x R)
Power
Resistance
Voltage
clear
Watts
Ohms
Volts
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Ohm’s Law Exam
Name ________________________________
Date_______________
Circle the best answer for each statement.
1. Voltage can be defined as:
A. Electrodynamic force
B. Electropotential force
C. Electrochemical force
D. Electromotive force
2. Current is the
A. Build up of electrons
B. Flow of electrons
C. Division of electrons
D. Passing of electrons
3. Resistance is the ___________ of/to current flow.
A. Opposite
B. Opposition
C. Result
D. Reverse
4. Voltage compares to __________ in a gas system.
A. Flow of gas
B. Restriction of gas flow
C. Pressure
D. Orifice effect
5. Current compares to ________ in a liquid piping system.
A. Orifice effect
B. Flow of product
C. Pressure pushing the product
D. Friction of the inside pipe wall
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6. Resistance compares to ___________ in a gas or liquid piping system.
A. Build up of pressure
B. Flow of product
C. Orifice effect
D. Pipe’s outside diameter Text.
7. Mathematically, Ohm’s Law takes on which form?
a. E = I/R
b. I =E/R
c. R = E x I
d. I = R/E
Solve Problems for an Unknown Quantity
(Show your work)
1. A circuit is drawing a current of 2 amps, and the resistance is 60 Ohms.
What is the voltage?
2. A 460- volt circuit operates at 100 amperes. What is the resistance of the
circuit?
3. What is the resistance in a circuit drawing 4 amps through a potential of
240 volts?
4. Apply the appropriate formula to answer each problem:
Volts
Ohms
Amps
a. 230
12
=
_________
b. 440
20
=
_________
c.
40 =
_________
120
Volts
Amps
Ohms
d.
240
4 =
_________
e.
12
5 =
_________
f.
24
8 =
_________
Ohms
Amps
Volts
g.
40
10 =
_________
h.
35
15 =
_________
i.
100
2.4 =
_________
j.
15
10 =
_________
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Ohm’s Law Exam KEY
Name ________________________________
Date_______________
Choose the right answer for each statement
1. Voltage can be defined as:
A. Electrodynamic force
B. Electropotential force
C. Electrochemical force
D. Electromotive force
2. Current is the
A. Build up of electrons
B. Flow of electrons
C. Division of electrons
D. Passing of electrons
3. Resistance is the ___________ of/to current flow.
A. Opposite
B. Opposition
C. Result
D. Reverse
4. Voltage compares to __________ in a gas system.
A. Flow of gas
B. Restriction of gas flow
C. Pressure
D. Orifice effect
5. Current compares to ________ in a liquid piping system.
A. Orifice effect
B. Flow of product
C. Pressure pushing the product
D. Friction of the inside pipe wall
6. Resistance compares to ___________ in a gas or liquid piping system.
A. Build up of pressure
B. Flow of product
C. Orifice effect
D. Pipe’s outside diameter Text
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7. Mathematically, Ohm’s Law takes on which form?
c. E = I/R
c. R = E x I
d. I =E/R
d. I = R/E
Solve Problems for an Unknown Quantity
(Show your work)
1. A circuit is drawing a current of 2 amps, and the resistance is 60 Ohms.
What is the voltage?
E=IxR
E = 2 x 60 = 120 volts
2. A 460- volt circuit operates at 100 amperes. What is the resistance of the
circuit?
R = E/I
R = 460/100 = 4.6 ohms
3. What is the resistance in a circuit drawing 4 amps through a potential of
240 volts?
R = E/ I
R = 240/4 = 60 ohms
4. Apply the appropriate formula to answer each problem:
Volts
a. 240
b. 440
c. 120
Volts
d.
e.
f.
240
12
24
Ohms
g.
h.
i.
j.
40
35
100
15
Ohms
12
20
40
=
=
=
Amps
Amps
E/R
E/I
4 =
5 =
8 =
Amps
10
15
2.4
10
=
=
=
=
20
22
3
Ohms
60
2.4
3
IxR
Volts
400
525
240
150
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