IEC Electrical Theory 1 - Sample Lesson

Lesson Theory Lesson TH-101 Electrical

LESSON Basic Principles TITLE and Circuit Theory

Electrical & Systems Training Series Electrical Theory I 1st Edition Student Manual

Purpose

This lesson introduces the law of electric charges and theories of current flow and provides direction for metric prefixes and metric conversions.

Homework

(Due at the beginning of this class) For this lesson, you should: • Thoroughly read the material contained within Lesson TH-101.

• Complete TH-101 Reading Worksheet.

(Due after this class) For this lesson, you should: • Complete Objective TH-101.1 Worksheet.

• Complete Objective TH-101.2 Worksheet.

• Read and complete Electrical Theory Lesson TH-101 Safety Worksheet.

Complete additional assignments or worksheets as directed by your instructor.

Objectives By the end of this lesson, you should: TH-101.1 TH-101.2

Develop a basic comprehension of the law of electric charges and theories of current flow.

Conduct conversions between English and metric units, and conduct conversions among metric prefixes.

TH-101-2

Basic Principles and Circuit Theory

Although much of the homework (due after this class) can be completed from having read the assignment, instructors should review the lesson material before this class to determine which topics require additional instruction. A preview of the next lesson should be included in the summary at the end of this class.

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Time permitting, those instructors who wish to expand on the objectives should refer to other reference material that is available to them.

Electrical Theory I (Student Manual)

Basic Principles and Circuit Theory

TH-101.1

TH-101-3

Electric Charges and Theories of Current Flow

Electron Theory Elements of an Atom All matter is composed of molecules. Molecules are comprised of different atoms. Each atom has a nucleus with electrons orbiting it. The nucleus is composed of protons and neutrons. (The neutrons are not shown in the drawing at the right.)

Generally, there are an equal number of electrons and protons in each atom. The electrons have a negative charge (−), and the protons have a positive charge (+). Neutrons carry no charge. The positive charge of the protons balances the negative charge of the electrons, and the electrons are held, or bound, in their orbit by this equal attraction. These electrons are referred to as bound electrons.

Free Electrons The electrons traveling around the nucleus in the outermost orbit are not as strongly held as those electrons that are in an orbit that is closer to the nucleus. These are called free electrons.

Consider NASA’s mission to send astronauts to the moon. First, the spacecraft was put into orbit around the earth. They initially didn’t “fly into space” because of the gravitational attraction of the Earth. Then their orbit was progressively expanded: they became less and less attracted to the Earth as they moved farther away from it. Then, when they applied sufficient force with their engines, the spacecraft did indeed overcome the Earth’s attractive force that held it in orbit, and away they went into space. Very careful planning went into this action. They timed the engine thrust so that their trajectory headed them toward our moon. When they got close enough to the moon, the moon’s gravitational force captured them in orbit around it.

Just like the spacecraft, free electrons can be forced out of their orbit around an atom and can be “captured” in the orbit of an adjacent atom. Instead of an onboard engine, however, an external

Electrical Theory I (Student Manual)

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Basic Principles and Circuit Theory

force must be applied to get these electrons out of orbit. The external force can be due to chemical action, friction, or by a magnetic field. When a free electron leaves an atom, it leaves behind a “hole” or void into which a free electron, from an adjacent atom, can enter.

Magnetism is the basis of electricity. Oppositely charged particles attract each other, and particles that have the same charge repel each other.

(+)(−) (−)(+) and (+)(+) (−)(−) Since electrons are negatively charged, the introduction of a negative force from a magnetic field will cause the free electrons to move away from the negative source. When this negative force is applied to a material, electrons can be forced out of orbit and pushed away from it. These free electrons will travel until they see a “hole” vacated by another free electron. Free electrons “flow” through a material from one atom to the next. This flow of electrons is termed “current flow.” Current flow is what makes all electrical equipment operate.

Current Current is the flow of electrons from one atom to another. Current flow is actually millions of electrons moving through a conductor. The number of electrons moving past a point in a conductor in a second’s time indicates the current INTENSITY. This is why current, as used in a calculation or formula, is abbreviated as I. So, I = current. Current is measured in amperes, or amps, using an ammeter. An amp, or ampere, is abbreviated as A. When 6.24 x 1018 (6,240,000,000,000,000,000) electrons are moving past a point in a conductor in a second’s time, then 1 amp of current is flowing. Some currents (as in electronics) can be very small, and some currents (as in power generation) can be very large. These quantities are frequently written in metric equivalents.

For example: where A = amperes = amps

1 microampere (abbreviated: μA) = 1 ÷ 1,000,000 A = .000001 A

1 milliampere (abbreviated: mA) = 1 ÷ 1,000 A = .001 A

1 kilo ampere (abbreviated: kA) = 1 × 1,000 A = 1,000 A

1 mega-amp (abbreviated: MA) = 1 × 1,000,000 A = 1,000,000 A Direction of Current Flow As previously stated, electrons (e−) are negatively charged and will flow toward a positively charged terminal. For example: An electrical circuit is formed when the positive (+) terminal (or post) of a battery is connected to a piece of wire, this wire is then connected to one terminal of a lamp (“light bulb”), the other lamp terminal is connected to another piece of wire, and this wire is then connected to the negative (−) terminal (or post) of the battery. Because “likes repel” and “unlikes attract,” electrons will leave from the negative battery terminal and travel through the wire, the lamp filament, through the other wire, and back into the battery through the positive terminal. This cycle is repeated.

Electrical Theory I (Student Manual)

Basic Principles and Circuit Theory

TH-101-5

Electrons will flow between two points whenever there is a difference in potential between the two points. This electron flow is current flow.

A coulomb is a unit of electric charge in the meter-kilogram-second-ampere system. This system is the basis of the SI system of physical units. The coulomb is defined as the quantity of electricity transported in one second (s) by a current of one ampere (A). One coulomb (C) is approximately 6.24 × 1018 electrons.

This can be expressed mathematically as follows.

C=A×s

Alternately, current can be mathematically expressed in terms of coulombs.

A = C/s

When applied to electricity, a joule (J) is a unit of energy. Joules are coulomb-volts (CV).

That is, when one coulomb of electrons passes through a potential difference of 1 volt, one joule of energy is used in the system. The quantity of joules can be determined by multiplying the number of coulombs (C) by the number of volts (V). This can be expressed mathematically as follows.

J=C×V

A watt (W) equals one joule of power radiated or dissipated for one second (J/s). One joule is equal to a watt-second (W·s). A kilowatt-hour (kW·h), often seen on residential electric meters, is equal to 3,600,000 J. These can be expressed mathematically as follows.

W = J/s

J=W×s

Or J = [kW/1000 W] × [hour/(60 sec)(60 min)] J = kWh/3,600,000 Or

1 kWh = 3,600,000 J

An application of the use of joules is the rating provided for surge protectors. This joule rating indicates how much energy the surge protector can absorb before it fails. A higher number indicates greater protection.

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Basic Principles and Circuit Theory

Voltage As stated before, a force must be applied to cause the electrons to move. Electricity is frequently compared to water flowing through a pipe. A force is required to cause water to flow in the pipe. This force could be from a pump or simple gravity (as from a water tower). The stronger the pump, the more water will flow. The bigger the pipe, the more water will flow. The same is true for electron flow.

The force required to cause electrons to flow in a circuit is called electromotive force or emf and exists because of the difference in potential between two points. Voltage is the most common term used to describe this force. Either E or V represents voltage in a calculation or formula. Voltage is measured in volts using a voltmeter. The unit of measurement for voltage is volts and is abbreviated V. Various means can be used to generate voltage. Storage batteries can be used. This is an electrochemical process where excess electrons on the negative battery terminal are transferred to the positive battery terminal by traveling through the conductors and various loads that are connected between the two terminals. These batteries can be re-charged with a charger that is powered from various sources, including wind, water, sunlight, or another power source. A schematic of a battery and lamp circuit is shown at the near right.

The terminals of the battery are represented by two lines, with the shorter line representing the negative terminal.

Another power source of limited capability is a thermocouple. When two dissimilar metals are joined at one end and the junction is heated, a small thermoelectric voltage is generated. Thermocouples are used in natural gas environmental air heating units, cooking equipment, and water heaters. When exposed to the heat of a pilot light, these thermocouples generate just enough voltage to power the gas solenoid valve circuit and hold the valve open to allow the unit to operate. When heat is removed (pilot light goes out), the thermocouple stops generating voltage. The solenoid valve closes, thus shutting off the gas supply to the equipment.

Conductors A material that consists of molecules that allow many electrons to move freely is called a conductor. Conductors are classified according to the number of electrons allowed to travel freely.

Remember, this is current flow. Most metals are excellent conductors. These include copper, brass, silver, aluminum, platinum, gold, and zinc. Copper is the most ecommonly used among these for electrical equipment because it is ebattery relatively inexpensive and also because it has other desirable physical characteristics that are required for product manufacture and use. lamp

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Basic Principles and Circuit Theory

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Insulators Some materials allow very, very few free electrons (remember—current flow). These are called insulators. Materials that are good insulators include some plastics, rubber, glass, mica, some ceramics, and air.

Electricians make use of both conductors and insulators. Lineman’s pliers are often constructed of steel (a conductor) with plastic (insulator) high dielectric covers on the handles. Another example of the use of both conductors and insulators is in the construction of electric cables used to supply electric power to equipment. Electricians call these “conductors” or “wires.”

Remember that some materials are not conductive but can be made conductive. Listed below are some examples of this: a) Clean and dry wood is an insulator but can become conductive if soaked with a somewhat conductive liquid, such as dirty water. Be aware that plywood is made from thin sheets of wood glued together. This glue may contain conductive materials. Insulating mats, made for the purpose, should be used for “hot work.” b) New leather boots with rubber soles are good insulators. But sweaty, dirty boots are NOT good insulators because sweat is salty and therefore a conductor. c) Pure distilled water is a perfect insulator. However, as chemicals such as chlorine, or salt, or other contaminates such as dirt are added, it becomes more and more conductive. For this reason, you would not put your body or any body parts into tap water or dirty water to operate energized electrical equipment. d) The dust covering insulated electrical wires in a panel will allow current to flow through the dust particles. This can be very dangerous to electricians and is why electrical equipment and conductors must be enclosed and kept free of dust and dirt.

For the reasons listed above, our insulated safety equipment must be kept clean and free of conductive contaminates. Keep this in mind when you inspect your equipment prior to using it!

When you get ready to trust your life to a rubber mat or gloves, are you wondering what cleaning solution was used to clean it? Was the cleaning solution conductive, or did it leave a residue that is conductive?

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Basic Principles and Circuit Theory

Semiconductors Semiconducting materials fall into the gray area between perfect conductors and perfect insulators. Although not naturally good conductors, certain materials can be made more (or less) conductive by adding impurities and changing the temperature or the energy applied. The most commonly used materials used to make semiconductors are silicon and germanium.

Semiconductor materials can be used to manufacture devices that have characteristics of both conductors and insulators. Many semiconductor devices will act like a conductor when an external force is applied in one direction. When the external force is applied in the opposite direction, the semiconductor device will act like an insulator. This principle is the basis for solid-state electronic devices that utilize semiconductors. These include silicon controlled rectifiers (SCRs), diodes, transistors, light-emitting diodes (LEDs), and solar cells.

Current Flow (I)

Diodes (one type shown at the near right and symbolized as shown at the far right) can be used to restrict current flow to only one direction.

Diode

Diode Symbol

As an example, a diode can be used in a circuit to permit a polarity-sensitive piezoelectric buzzer to sound only when the correct polarity is applied. This application is shown in the circuit diagrams that follow. In the left diagram, the buzzer is correctly connected to the battery and the diode is used to permit current flow in only one direction. In the right diagram, the battery has been incorrectly connected to the buzzer and the diode prohibits incorrect current flow.

– +

I

– +

The diode is forward biased and permits current flow.

+ –

– +

The diode is reverse biased and prohibits current flow.

Static Electricity To an electrician, static electricity has virtually no practical use. Static electricity is defined as a collection of charged particles at rest (static). Generally, these charged particles collect on insulated surfaces. When charges of opposite polarity accumulate on two separated surfaces, the charges from one surface can be discharged to the other under certain circumstances.

Electrical Theory I (Student Manual)

Basic Principles and Circuit Theory

TH-101-9

Voltage Sources Although a battery is considered a voltage source, the most common source of voltage is a generator (or alternator). Generators produce voltage when the center shaft is turned (or rotated) by an external force. External forces include wind; hydroelectric (due to gravity); wave motion (due to wind and tides); and internal combustion engines that use natural gas, gasoline, diesel, coal, etc. Look under the hood of your can where you will find a generator that has its center shaft turned by the rotary action of the engine.

As with current, voltages can be very small or very large, and metric equivalents are used to represent these quantities.

1 microvolt (μV) = 1 ÷ 1,000,000 V = .000001 V

1 millivolt (mV) = 1 ÷ 1,000 V = .001 V

1 kilovolt (kV) = 1 × 1,000 V = 1,000 V

1 megavolt (MV) = 1 × 1,000,000 V = 1,000,000 V

Let’s review the elements of an electric circuit we have covered so far. These are current and voltage.

When the voltage source has two terminals, with one marked + and one marked − (as with a battery or a dc power supply), the voltage is constant. This voltage and the circuit current are termed DC for direct current. When the voltage source is a generator or a transformer, the circuit voltage and current are termed AC for alternating current. You will learn more about AC in your future studies.

90 minutes Students need to completely understand the principles set forth in this objective. You should use Objective TH-101.1 Worksheet for reinforcement. This worksheet can be used during class or assigned for homework.

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For your reference, additional materials such as Electrical Principles and Practices, Delmar’s Standard Textbook of Electricity, or Electricity 1-7, may be available to you from your supervisor.

Electrical Theory I (Student Manual)

TH-101-10

TH-101.2

Basic Principles and Circuit Theory

Metric Prefixes and Metric Conversions

Converting ºF to ºC Use the following formula when you are given a temperature in ºF and you need to convert this to ºC: [ºF - 32] × [5 ÷ 9] = ? ºC Converting ºC to ºF Use the following when you are given a temperature in ºC and you need to convert this to ºF: [(ºC) × (9 ÷ 5)] + 32 = ? ºF The rest of the world measures everything in metric units. They measure temperature in degrees Celsius (or centigrade). The United States has delayed the conversion to metric measurements for many years. Current editions of the NEC® appear with the English measurement in parentheses following the metric measurement. Future NEC® editions are planned to contain only the metric measurements.

Linear Conversions It really isn’t too difficult to learn the metric system. It’s simply a matter of getting some relative idea of the size of each unit of measure. For example, just as when you learned that an inch was about as long as the red line shown at the right, now you can learn that the length of a centimeter (abbreviated cm) is about as long as the green line shown at the right.

1 inch 1 cm

The metric system is actually much easier to work with than the English system. The metric system is simply the base unit [the meter (abbreviated m) for example is the base unit of measure for length] multiplied (or divided) by 10, or 100, or any multiple of 10.

While in the English system you had to learn that 12 inches = 1 foot, 3 feet = 1 yard, and 5280 feet = 1 mile, the metric system is very simple. 10 millimeters = 1 cm, 100 centimeters = 1 meter, and 1000 meters = 1 kilometer (abbreviated km). Using the conversion tables shown on the following page, you can see that 1 meter is about 39 inches long and that 3 meters is about 10 feet long.

Learning to associate metric measurements to some known measurement is all it’s going to take for you to learn this system.

To convert among metric prefixes, refer to the table on the following page.

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30 minutes Traditionally, students have some trouble distinguishing among the abbreviations used for the metric prefixes, such as m versus M.

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TH-101-11

Common Lengths and Equivalents one inch

one foot

one yard

one meter

= = = = = = = = = = = = = = = =

2.54 25.4 0.0254 12 0.3048 30.48 304.8 3 36 0.9144 914.4 100 1,000 1.093 3.281 39.37

centimeters millimeters meter inches meter centimeters millimeters feet inches meter millimeters centimeters millimeters yards feet inches

Common Conversions with Abbreviations

inches (in) × 0.0254 inches (in) × 0.254 inches (in) × 2.54 inches (in) × 25.4 feet (ft) × 0.3048 miles (mi) × 1.609

= meters (m) = decimeters (dm) = centimeters (cm) = millimeters (mm) = meters (m) = kilometers (km)

square inches (in2) × 6.452 square feet (ft2) × 0.093 square yards (yd2) × 0.8361

= square centimeters (cm2) = square meters (m2) = square meters (m2)

millimeters (mm) × 0.03937 centimeters (cm) × 0.3937 meters (m) × 3.2808 kilometers (km) × 0.621

= inches (in) = inches (in) = feet (ft) = miles (mi)

kilometers (km) × 1000

= meters (m)

square centimeters (cm2) × 0.155 square meters (m2) × 10.764 square meters (m2) × 1.196

= square inches (in2) = square feet (ft2) = square yards (yd2)

Electrical Theory I (Student Manual)

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TH-101-12 Basic Principles and Circuit Theory

Basic Principles and Circuit Theory

TH-101-13

Tools Required for this Lesson: None Demonstrations—Samples—Activities—Labs Demonstrate DC current, resistance, and voltage measurements to reinforce the discussions of circuit theory.

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Equipment: DVD, VCR, Internet websites, etc.: http://www.industry.usa.siemens.com/services/us/en/industry-services/training/selfstudy-courses/quick-step-courses/Pages/quick-step-courses.aspx Materials Required for this Lesson: You will need to have an “in-line” ammeter (capable of DC current measurement), a voltmeter, a battery, and a resistive load (incandescent lamp, carbon resistor, heating element, etc). A flashlight could be substituted for the battery and load.)

Safety 15 minutes

Summary

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Discuss Electrical Theory Lesson TH-101 Safety Worksheet.

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85 minutes Recap tonight’s discussions and give a synopsis of the next lesson’s material to enable the students to better understand the next lesson’s reading assignments and to complete the Reading Worksheet for the next lesson.

Assessment – Quiz for this lesson is MANDATORY.

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20 minutes Refer to the Assessment Bank questions and problems for quizzes.

Within an assessment bank, a question used on a worksheet is so noted in the question’s information field.

Electrical Theory I (Student Manual)

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Electrical Theory Lesson TH-101 Safety Worksheet General Safety Items Keep oily cloths away from oxygen (danger of explosion).

Always light torches with a “torch lighter” (never use a match or cigarette and never light torches in a keg or drum).

Open compressed gas cylinders slowly to avoid valve damage.

Keep salamanders or other portable heaters away from combustible materials.

Make sure engines in buildings are away from combustibles and exhaust is properly ventilated.

After work, check clothing for hidden hot slag or molten metal. Do not wear oil-soaked clothing.

Check for a clear path first. Then have a clear view while carrying load.

Face a ladder when climbing. Use both hands. Use hand line or material hoist to lift loads.

Use only sturdy ladders on a firm base. Where possible, angle out the base one-fourth of the working length of the ladder.

Keep area clear of debris.

Have a ladder reach at least three feet above the landing for easy access. Tie off the ladder at the top (secure the bottom and brace long ladders).

Use a scaffold if solid footing or safe ladder access is not possible. The scaffold must be made of straight-grained lumber, free of defects and knots. Test plank strength before use. Platform planks should overlap supports not less than 6 inches nor more than 12 inches; these should be secured from shifting.

Consider all wires “live” until checked and locked out. Keep safe distance from “live” electricity.

Have electrical power tools and equipment properly grounded. Do not use electrical power tools or equipment while standing in water.

All electrical power tools and extension cords should have good insulation. Damaged cords should be replaced, not repaired. Never remove the ground prong on a plug for lack of a grounded outlet.

Only qualified personnel should make electrical repairs or installations. Do not use metal ladders and hats near electricity.

Have all cords, leads, and hose placed safely to avoid damage or tripping hazards. Keep them away from oil and grease.

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Basic Principles and Circuit Theory

TH-101-15

Remove or clinch nails in old lumber.

Clean up oil, grease, and water spills right away. Delay can cause an accident.

Keep loose materials off stairs, walkways, ramps, platforms, etc.

Electrical Theory I (Student Manual)

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Electrical Theory I (Student Manual)

Basic Principles and Circuit Theory

Lesson Theory Lesson TH-101 Electrical

LESSON Basic Principles TITLE and Circuit Theory

Electrical & Systems Training Series Electrical Theory I 1st Edition Student Workbook

TH-101 Reading Worksheet ____ � 1. DC is an abbreviation for ___. a. Don’t Charge b. Diatomic Changes

c. Direct Current d. Definite Calibration

____ � 2. What other term may be used interchangeably with potential and electromotive force? a. Impulse b. Voltage c. Ampere d. Joule ____ � 3. A microampere is what fraction of an ampere? a. 1/1000 c. 1/100,000 b. 1/10,000 d. 1/1,000,000 ____ � 4. In order to have electric current present, free electrons must do what continuously? a. Discharge b. Bond c. Charge d. Flow ____ � 5. What kind of electrical charge does an electron have? a. Positive b. Neutral c. Static ____ � 6. Opposite charges ___. a. have no effect on one another b. repel

d. Negative

c. both repel and attract d. attract

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Basic Principles and Circuit Theory

____ � 7. 0°C = ___°F a. 9

b. 32

c. 5

d. 58

e. 0

____ � 8. 212°F = ___°C a. 32

b. 706

c. 100

d. 86

e. 118

____ � 9. AC is an abbreviation for ___. a. Action Calibration b. Alternating Current

c. Amplitude Cancellation d. Always Charged

____ 10. Three meters equals approximately ___. a. one foot b. 39 inches c. 7.62 feet

d. 25.4 feet

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e. 10 feet

TH-101 Reading Worksheet – Answer Key

1. C 2. B 3. D 4. D 5. D 6. D 7. B

8. C

9. B 10. E

Q-ID: AP1-101.03.035 REF: Obj TH-101.1 Reading Assignment Q-ID: AP1-101.03.007 REF: Obj TH-101.1 Reading Assignment Q-ID: AP1-105.02.030 REF: Obj TH-101.2 Reading Assignment Q-ID: AP1-101.03.005 REF: Obj TH-101.1 Reading Assignment Q-ID: AP1-101.03.001 REF: Obj TH-101.1 Reading Assignment Q-ID: AP1-101.03.002 REF: Obj TH-101.1 Reading Assignment Q-ID: AP1-105.02.002 REF: Obj TH-101.2 Reading Assignment [(0) × (9 ÷ 5)] + 32 = 32°F Q-ID: AP1-105.02.006 REF: Obj TH-101.2 Reading Assignment [212 − 32] × (5 ÷ 9) = 100°C Q-ID: AP1-101.03.043 REF: Obj TH-101.1 Reading Assignment Q-ID: AP1-105.02.026 REF: Obj TH-101.2 Reading Assignment

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Electrical Theory I (Student Workbook)

Basic Principles and Circuit Theory

TH-101-WB3

Objective TH-101.1 Worksheet 1. In the spaces provided on the drawing shown below, label the parts of the atom. a.

b.

c.

2. Current flow is the same thing as __________________________ flow.

3. List 4 insulators:

_______________________ _______________________ _______________________ _______________________

4. List 4 conductors: _______________________ _______________________ _______________________ _______________________ 5. Current is measured in __________________________.

6. __________________________ force is the component of a circuit that causes electrons to flow. ____ � 7. 105 mA = ___ A a. .105 b. 105,000

c. 10.5

d. .000105

e. 1.05

____ � 8. 1.2 MV = ___ V a. 1,200 b. 1,200,000

c. .0012

d. 12,000

e. 120

____ � 9. Which of these symbols is used to represent a battery? a. b. c. d.

+ –

____ 10. .0001 A = ___ µA a. 1 b. 10

c. 1,000

d. .1

e. 100

____ 11. 10 A = ___ kA or KA a. 100 b. .01

c. .001

d. .1

e. 1

Electrical Theory I (Student Workbook)

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s e t o N t n Stude Objective TH-101.1 Worksheet – Answer Key Electron

Proton

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1.

Q-ID: AP1-101.03.048 2. electron Q-ID: AP1-101.03.051 3. Plastic, rubber, glass, mica, some ceramics, air, etc.

Q-ID: AP1-101.03.049 4. Copper, brass, silver, aluminum, platinum, Q-ID: AP1-101.03.050

gold, zinc, titanium, iron, steel, etc.

5. amperes or amps Q-ID: AP1-101.03.052 6. Electromotive Q-ID: AP1-101.03.053 7. A Q-ID: AP1-101.03.022 8. B Q-ID: AP1-101.03.023 9. A Q-ID: AP1-101.03.042 10. E Q-ID: AP1-101.03.008 11. B Q-ID: AP1-101.03.018

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Electrical Theory I (Student Workbook)

Basic Principles and Circuit Theory

TH-101-WB5

Objective TH-101.2 Worksheet ____ � 1. 7,200 V = ___ kV a. 7,200,000 b. 7,200

c. 7.2 d. .0072

____ � 2. 100 MW = ___ W a. .000001

b. .0001

e. none of these

c. 100,000,000

d. 100,000

____ � 3. 565 µA = ___ A a. 565 b. 565,000

c. .000565 d. .565

e. none of these

____ � 4. 7.3 MΩ = ___ Ω a. .00073 b. 7,300,000

c. 73,000 d. .0073

e. none of these

____ � 5. 200 kA = ___ A a. .0002 b. 200,000

c. .2 d. 200,000,000

e. none of these

____ � 6. 38°C = ___°F a. 100

b. 53

c. 11

d. 70

e. 126

____ � 7. 2.5 m equals ___ feet. a. 8.2 b. .76

c. 1.32

d. 3.28

____ � 8. 1¼ inch equals ___ mm. a. 2.032 b. 20.32

c. 31.75

d. 1.92

____ � 9. What is the Fahrenheit rating of a 60°C cable? a. 140 ____ 10. 3.2 kΩ = ___ Ω a. 3.2 b. 3,200,000

b. 182

c. 32,000 d. .0032

c. 190

d. 160

e. none of these

Electrical Theory I (Student Workbook)

TH-101-WB6

Basic Principles and Circuit Theory

____ 11. 100째F = ___째C a. 80

b. 73

c. 38

d. 212

e. 43

____ 12. 194째F = ___째C a. 140

b. 126

c. 381

d. 76

e. 90

____ 13. 37.5 kVA = ___ VA a. 375 b. 375,000

c. .0375 d. 3,750

e. none of these

____ 14. 106 A = ___ kA a. 106,000 b. 10.6

c. .106 d. 1.06

e. none of these

____ 15. 480 V = ___ kV a. 480,000 b. 48

c. .48 d. 4,800

e. none of these

____ 16. 32 mm equals ___ inches. a. .00123 b. 1.26

c. 8.13

d. .813

____ 17. 18 inches equals ___ mm. a. 220 b. 1.41

c. 457

d. .0022

____ 18. 1/16 inch equals ___ mm. a. .159 b. 6.3

c. 1.59

d. .63

____ 19. 1,300 W = ___ kW a. 130 b. 1.3

Electrical Theory I (Student Workbook)

c. 13 d. 1,300,000

e. none of these

Basic Principles and Circuit Theory

TH-101-WB7

s e t o N t n e Stud Objective TH-101.2 Worksheet – Answer Key

1. C Q-ID: AP1-105.02.090 2. C Q-ID: AP1-105.02.039 3. C Q-ID: AP1-105.02.042 4. B Q-ID: AP1-105.02.094 5. B Q-ID: AP1-105.02.093 6. A Q-ID: AP1-105.02.005

[(38) × (9 ÷ 5)] + 32 = 100°F 7. A Q-ID: AP1-105.02.029 3.2808 ft

2.5 m × 1 m = 8.2 feet 8. C Q-ID: AP1-105.02.020 1 25.4 mm

1 4 inch × 1 inch = 31.75 mm 9. A Q-ID: AP1-105.02.013

(9/5 × 60) + 32 = 108 + 32 = 140 10. E Q-ID: AP1-105.02.095 11. C Q-ID: AP1-105.02.007

[100 − 32] × (5 ÷ 9) = 38°C 12. E Q-ID: AP1-105.02.008

[194 − 32] × (5 ÷ 9) = 90°C 13. E Q-ID: AP1-105.02.092 14. C Q-ID: AP1-105.02.097 15. C Q-ID: AP1-105.02.091 16. B Q-ID: AP1-105.02.028 .03937 in 32 mm × 1 mm = 1.26 inches

17. C Q-ID: AP1-105.02.021 25.4 mm

18 inches × 1 inch = 457.2 mm 18. C Q-ID: AP1-105.02.019 1 25.4 mm

16 inch × 1 inch = 1.5875 mm 19. B Q-ID: AP1-105.02.096

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Electrical Theory I (Student Workbook)

TH-101-WB8

Basic Principles and Circuit Theory

Electrical Theory Lesson TH-101 Safety Worksheet Questions ____ � 1. All circuit wires should be considered ___ until tested. a. energized (live) b. de-energized (dead) ____ � 2. Platform planks should overlap supports not less than ___ inches nor more than __ inches and should be secured from shifting. a. 4 - 12 b. 4 - 8 c. 6 - 8 d. 6 - 12 ____ � 3. Damaged cords on power tools should be ___. a. replaced b. repaired ____ � 4. Electrical materials such as luminaires (light fixtures) should be stored on the closest stairway landing to where they will be installed. a. True b. False ____ � 5. Ladders should extend at least ___ feet above the landing for easy access. a. 6 c. 3 b. 2 d. none of these

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Electrical Theory Lesson TH-101 Safety Worksheet Questions – Answer Key 1.

2.

3.

4.

5.

A D A B C

Q-ID: AP1-105.SAF.005 Q-ID: AP1-105.SAF.001 Q-ID: AP1-105.SAF.004 Q-ID: AP1-105.SAF.003 Q-ID: AP1-105.SAF.002

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Electrical Theory I (Student Workbook)