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Copyright © Texas Education Agency, 2013. All rights reserved.

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Lesson Plan

Course Title Electronics

Session Title Voltage and Its Measurements

Performance Objective Upon completion of this lesson, the student will be able to demonstrate the ability to measure and compare the voltage of different batteries and measure the voltage drops in a DC circuit. This knowledge will be evidenced by correctly performing the procedures outlined on the lab activity sheets and by scoring an 85 percent on the voltage exam.

Specific Objectives

Match terms associated with voltage and measurement with their definitions Name three common sources of voltage Select principal parts of a typical voltmeter Match symbols and abbreviations related to voltage and measurement with their

definitions Arrange the procedures for measuring current with a DC voltmeter in order State Kirchhoff’s law of voltage Discuss current flow in a resistive circuit State the formulas for voltage drops in resistive circuits Read voltmeter indications Demonstrate the ability to measure and compare current at two points of a

circuit Demonstrate the ability to measure and compare current in a circuit at two

different voltage levels

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. Electronics

130.368 (c) o (1) The student demonstrates the skills necessary for success in the

workplace. The student is expected to: (A) identify employment and career opportunities, including differences


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between an engineering technician, engineering technologist, and engineer; (B) investigate and work toward industry certifications; (C) demonstrate the principles of teamwork related to engineering and technology; (D) identify and use appropriate work habits; (E) identify governmental regulations for health and safety in the workplace related to electronics; and (F) discuss ethical issues related to electronics.

130.368 (c) o (4) The student practices safe and proper work habits. The student is

expected to: (A) master relevant safety tests; (B) follow safety guidelines as described in various manuals, instructions, and regulations; (C) identify and classify hazardous materials and wastes according to Occupational Safety and Health Administration regulations and industry standards; (D) dispose of hazardous materials and wastes appropriately; (E) perform maintenance on selected tools, equipment, and machines; (F) handle and store tools and materials correctly; and (G) describe the results of negligent or improper maintenance.

130.368 (c) o (5) The student implements the concepts and skills that form the technical

knowledge of electronics using project-based assessments. The student is expected to:

(A) apply Ohm's law, Kirchhoff's laws, and power laws; (C) demonstrate knowledge of the fundamentals of electronics theory; and (D) perform electrical-electronic troubleshooting assignments.

130.368 (c) o (6) The student applies the concepts and skills to simulated and actual work

situations. The student is expected to: (A) measure and calculate resistance, current, voltage, and power in series, parallel, and complex circuits.

130.368 (c) o (8) The student learns the function and application of the tools, equipment,

and materials used in electronics through project-based assignments. The student is expected to:


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(A) safely use tools and laboratory equipment to construct and repair circuits; and (B) use precision measuring instruments to analyze circuits and prototypes.

Interdisciplinary Correlations

Computer Maintenance

130.273(c) o (4) The student acquires an understanding of computer technologies. The

student is expected to: (D) explain proper troubleshooting techniques as related to computer hardware.

130.273(c) o (5) The student knows the proper function and application of the tools,

equipment, and materials used in computer technologies. The student is expected to:

(A) demonstrate safe use of equipment in computer technologies such as hand and power tools.

130.273(c) o (6) The student applies the concepts and skills of the trade in simulated work

situations. The student is expected to: (A) use electronic test equipment to measure current, voltage, power, and resistance.

Occupational Correlation (O*Net –www.onetonline.org) Job Title: Wind Turbine Service Technicians O*Net Number: 49-9081.00 Reported Job Titles: (data collection underway as of June 2013) Tasks

Inspect or repair fiberglass turbine blades. Troubleshoot or repair mechanical, hydraulic, or electrical malfunctions related

to variable pitch systems, variable speed control systems, converter systems, or related components.

Climb wind turbine towers to inspect, maintain, or repair equipment. Diagnose problems involving wind turbine generators or control systems.


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Perform routine maintenance on wind turbine equipment, underground transmission systems, wind fields substations, or fiber optic sensing and control systems.

Start or restart wind turbine generator systems to ensure proper operations. Test electrical components of wind systems with devices such as voltage testers,

multimeters, oscilloscopes, infrared testers, or fiber optic equipment. Test structures, controls, or mechanical, hydraulic, or electrical systems,

according to test plans or in coordination with engineers. Assist in assembly of individual wind generators or construction of wind farms. Collect turbine data for testing or research and analysis.

Soft Skills (data collection underway)

References

Buchla, D. and Floyd, T. (2004). The science of electronics: DC/AC. Upper Saddle River, NJ: Pearson Prentice Hall.

Floyd, T. (1993). Principles of electric circuits: Electron flow version. Don Mills, Ontario: Macmillian Publishing Co.

Robertson, L. (1980). Basic electronics I. Stillwater, OK: Mid-American Vocational Curriculum Consortium, Inc.

Instructional Aids

Voltage and Its Measurements slide presentation and notes Voltage and Its Measurements: Lab Activity #1- Measure and Compare the

Voltages of Three Different Batteries handout and answer key Voltage and Its Measurements: Lab Activity #2- Measure the Voltage Drop in a

DC Circuit handout and answer key Voltage and Its Measurement Exam I and answer key Electrical Measurement Exam II and answer key

Materials Needed

Assortment of resistors Multimeters or voltmeters Power supply Breadboards and leads Dry erase markers Three batteries with different voltages (1.5 volt, 9 volt, etc.) Lamp or load (hair dryer, heavy duty drill) Switch Calculator


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Equipment Needed

Computer Projector and screen Whiteboard

Learner Preparation Read chapter on measurement in textbooks.

Introduction

Introduction (LSI Quadrant I)

Say o It is one thing to know the theory behind electricity and electronics, and it is

another thing to be able to apply that knowledge on the job. o One of the main duties any technician does on the job is to maintain equipment.

Ask o Can you tell me some of the things a technician would do to maintain

equipment?

Say o Many of you mentioned equipment repair, and that is certainly important. o Another major aspect of maintenance is to perform preventive maintenance, in

which you work on equipment that is not broken at regular intervals, in order to keep it from breaking down.

o For either of these tasks, taking electrical measurements properly is critical.

Ask o What happens if you measure something and you are not using the

measurement tool or device correctly?

Say o That is right, it will either appear broken when it is not, or it will appear OK when

it is actually broken.

Ask o What else?

Say o Yes, you can damage either the equipment itself or the measuring device. o Therefore, it is important that we know how to use our electrical tools correctly. o A multimeter is one of the most important tools you will use as a technician, and

it is important to learn how it works and how to use it correctly and safely.

Outline


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Teachers can use the slide presentation, note pages, and handouts in conjunction with the following outline.

Outline (LSI Quadrant II):

Teacher Notes:

I. Overview A. The goals represent the desired outcomes; the

overview represents the process and sequence. B. The most important outcome is that the

student be able to use a multimeter correctly and safely.

C. Start with terms, definitions, voltage sources, and symbols.

D. This section is mostly a review of previous lessons.

(Slides 1-5)

II. Basic electrical measurement A. This section is designed to be covered with

students having access to a multimeter. B. Multimeters will look different and may have

different features and types of measurement. C. Each individual type of measurement is similar

because all meters work the same way. D. This section is designed to get the student

familiar with the meter; each type of measurement will be covered in more detail later in the lesson.

(Slides 6-8) This section provides an important overview for the types of measurement that are covered in more detail later in the lesson. Additional details may create confusion; this overview is necessarily simple to provide the basics of measurement and operation. This section should be referenced when covering specifics in more detail later.

III. Principal parts of a voltmeter A. Covers test probes, the function selector

switch, and the display. B. The display can be either analog or digital. C. Analog displays are older and nearly obsolete,

but students may still come across them and need to be able to read ranges from the dial (0-250 vs. 0-10 VDC, for example).

(Slide 9-19)

IV. Measurement overview A. Introduction to voltage measurement.

(Slides 20-24)


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B. Introduction to resistance measurement. C. Introduction to current measurement. D. Other measurements.

V. Procedures for using a multimeter A. Provides step-by-step instructions for a voltage

measurement. B. Many meters are auto ranging; they will not

have a range selector. C. Make sure leads are in the voltage connection,

not the current connection. D. Common is the same as ground, and that lead

position is always used for voltage, resistance, and current.

(Slides 25-27)

VI. Electrical measurement theory and practice A. All meters use Ohm’s Law as the basis for

measurement. B. Students can use Ohm’s Law to calculate values

that are to be measured. C. Use the Ohm’s Law circle to aid understanding

in which formula to use for which value. D. Kirchhoff’s Law states that voltage drops in a

circuit add up to the supply voltage. E. Provide components for students to build a

circuit. F. First, have students calculate values using

component values. G. Second, have students measure those values

and verify their calculations.

(Slides 28-33)

VII. How DMMs measure voltage A. An analog meter uses something called a

D’Arsonval meter, which is where magnetic forces provide needle deflection (which is not covered).

B. Digital meters do not have an analog display or needle and use a different (electronic) method to measure voltage and current.

C. That method is outlined and uses a count. D. This slide is optional depending on student level

of interest. E. Slide 35 provides a summary of the voltage

(Slides 34-35) Make sure that when you are going over Slide 35’s summary, you also refer back to the overview of voltage measurement on Slide 20.


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measurement process.

VIII. RMS vs. Average vs. DC voltage A. Average voltage and RMS voltage are ways to

indicate AC voltage values because the actual value is varying between +178 and -178 V (P-P) over each cycle.

B. The average voltage is from rectified AC (with only positive pulses) because average for a true sine wave is zero.

C. When rectified, average voltage will be the equivalent amount of DC voltage the AC can create.

D. The RMS value is the heating value of the AC wave.

E. AC voltage creates more heat than DC voltage. F. A component’s power rating is related to the

amount of heat the component can handle whether the voltage is AC or DC.

G. If the voltage signal is not a true sine wave, the RMS value the meter indicates will not be accurate.

(Slides 36-38) RMS is the Root Mean Square or effective heating value of any AC voltage or current waveform (Slide 37)

IX. How DMMs measure resistance A. Refer back to the overview from Slide 11. B. The circuit must be de-energized because the

meter needs to supply a reference voltage to the circuit.

C. Resistance values can have a large range, so make sure to look at the multiplier or range.

D. The practice example uses one meter to measure the input resistance of another; this reading will be high.

E. Give students a selection of resistors from which to take their own measurements.

F. Resistor color code to determine the nominal value is covered in another lesson.

(Slide 39)

X. Current measurement A. Current measurement uses different lead

connection positions. B. This is because current measurement requires

completely different meter characteristics than

(Slides 40-42)


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resistance or voltage measurement. C. Meter resistance is high for voltage

measurement and low (ideally zero) for current measurement.

D. Leaving the leads in the current measurement position can be dangerous to the student and the meter.

E. Because current is a different and dangerous type of measurement, oftentimes current probes are used instead of test leads.

F. Current probes clamp on around an energized wire without touching the wire or changing the circuit.

XI. DMM display A. The display is different from a calculator and

can be confusing. B. A meter typically cannot display values over a

complete range. C. It is the first digit that is restricted. D. Meter accuracy is not restricted by the display

range, but meter resolution is.

(Slides 43-46) Make sure students understand that just because a meter displays a particular value, it does not mean that value is accurate (e.g., student may use all digits when only two are correct).

XII. Teacher Demonstration A. Measure with a voltmeter. B. Measure voltage drops in resistive circuit. C. Demonstrate each type of measurement so

students know the proper technique

XIII. Lab activities A. Voltage and Its Measurements: Lab Activity #1:

Measure and Compare the Voltages of Three Different Batteries

B. Voltage and Its Measurements: Lab Activity #2: Measure the Voltage Drop in a DC Circuit

XIV. Exams A. Voltage and Its Measurement Exam I B. Electrical Measurement Exam II

Teacher will grade exam. Students are required to score at least 85 percent on the exam.

Application


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Guided Practice (LSI Quadrant III)

The students will observe, ask questions, and analyze the demonstration presented by the teacher.

The teacher will use materials as listed in the lab activities to instruct how to read, measure with, and record data needed.

Voltage and Its Measurements: Lab Activity #1: Measure and Compare the Voltages of Three Different Batteries and Key

Voltage and Its Measurements: Lab Activity #2: Measure the Voltage Drop in a DC Circuit and Key

Independent Practice (LSI Quadrant III) The student will replicate the lab activities. Then, the student will answer the discussion questions at the end of each lab and turn sheets in for evaluation.

Voltage and Its Measurements: Lab Activity #1: Measure and Compare the Voltages of Three Different Batteries

Voltage and Its Measurements: Lab Activity #2: Measure the Voltage Drop in a DC Circuit

Summary

Review (LSI Quadrants I and IV)

Question o What are three common sources of voltage?

Answer o Batteries o Generators / alternators o Electronic power supplies

Question o What are the principal parts of a voltmeter (multimeter)?

Answer o Connecting leads or probes o Function switch o Multiple use scales o Range switch

Question o What is polarity in a resistive circuit?

Answer o End nearer negative of supply is negative.


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o End nearer positive of supply is positive.

Question o What are the formulas for voltage drops in a resistive circuit?

Answer o Voltage drops in circuit equal the power source o Algebraic sum of voltage drops equal zero

Evaluation

Informal Assessment (LSI Quadrant III) The teacher will monitor each student (or small groups) as they individually work to complete the assignments. If re-teach is needed on any information or procedure, all those involved will stop and participate in the re-teach. The teacher should always check each setup for accuracy and completeness.

Formal Assessment (LSI Quadrant III, IV) The student will be assessed by the accuracy of the completed assignments:

o Voltage and Its Measurements: Lab Activity #1: Measure and Compare the Voltages of Three Different Batteries

o Voltage and Its Measurements: Lab Activity #2: Measure the Voltage Drop in a DC Circuit

o The student will be assessed by the accuracy of the exam. o Voltage and Its Measurement Exam I o Electrical Measurement Exam II

Extension

Extension/Enrichment (LSI Quadrant IV)

The teacher should have students, who understand and demonstrate voltage measurement accurately, assist other students who might not understand the procedures.

The use of the voltmeter becomes a vital part of the technical skills needed in industry. Students can create a list of places and events where voltage and accurate measurements are required.


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Name: ____________________________________ Class: ________ Date ___/___/___

Voltage and Its Measurements: Lab Activity #1 Measure and Compare the Voltages of Three Different Batteries

Tools and Equipment

Multimeter or voltmeter with leads

Three batteries with different voltages

Procedure

1. Check to see that the meter is a DC meter. If it is a multimeter, make sure it is set to

DC.

2. Place the test leads in their proper connectors in the meter. (Note: The negative [black] lead goes to the "-" connector, and the positive [red] lead goes to the "+" connector)

3. Set the full-scale reading on the voltmeter higher than expected voltage.

4. Hold the test leads by the insulated part.

(Caution: touching the metal part could make you a part of the circuit and result in a shock)

5. Connect the negative lead to the negative terminal of a battery, and then connect

the positive lead to the positive terminal of the battery.

6. Read and record the voltmeter indication. 7. Disconnect one of the meter leads and after the voltmeter goes to zero, reconnect

the lead. 8. Read and record the voltmeter indication again. 9. Repeat steps 6, 7, and 8 a third time. 10. Repeat steps 6, 7, and 8 for each of the other two batteries. Repeat until you record

a total of nine voltmeter readings.


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Name: ____________________________________ Class: ________ Date ___/___/___

Voltmeter Readings of Batteries_____________________________________________

Battery 1 _________, _________, _________ Battery 2 _________, _________, _________ Battery 3 _________, _________, _________

11. Return meters and batteries to proper storage area.

Analysis

Note: Discuss the following in class and write your responses.

The importance of connecting the positive lead to the positive terminal and the negative lead to the negative terminal

How to obtain an accurate voltmeter reading if the meter pointer does not fall exactly on a scale mark

Compare the advantages and disadvantages of multimeters with single purpose meters

How the range of the voltmeter is determined

The differences of the three readings taken on a battery


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Name: _________________KEY________________________ Class: ________ Date ___/___/___

Voltage and Its Measurements: Lab Activity #1 Key Measure and Compare the Voltages of Three Different Batteries

Tools and Equipment


Three batteries with different voltages

Procedure

1. Check to see that the meter is a DC meter. If it is a multimeter, make sure it is set to

DC.

2. Place the test leads in their proper connectors in the meter. (Note: The negative [black] lead goes to the "-" connector, and the positive [red] lead goes to the "+" connector)

3. Set the full-scale reading on the voltmeter higher than expected voltage.

4. Hold the test leads by the insulated part.

(Caution: touching the metal part could make you a part of the circuit and result in a shock)

5. Connect the negative lead to the negative terminal of a battery, and then connect

the positive lead to the positive terminal of the battery.

6. Read and record the voltmeter indication. 7. Disconnect one of the meter leads and after the voltmeter goes to zero, reconnect

the lead. 8. Read and record the voltmeter indication again. 9. Repeat steps 6, 7, and 8 a third time. 10. Repeat steps 6, 7, and 8 for each of the other two batteries. Repeat until you record

a total of nine voltmeter readings.


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Voltmeter Readings of Batteries____________________________________________________

Teacher’s note: set up the batteries so that Battery #1 is a 1.5 volt battery, Battery #2 is a 9 volt battery, and Batter #3 is a series of two or three batteries.

Battery 1 _________, _________, _________ (approximately 1.5 volts) Battery 2 _________, _________, _________ (approximately 9 volts) Battery 3 _________, _________, _________ (Voltage should be consistent but will vary depending on the series circuit)

11. Return meters and batteries to proper storage area.

Analysis

Note: Discuss the following in class and write your responses.

The importance of connecting the positive lead to the positive terminal and the negative lead to the negative terminal

o You do not want to destroy the meter reading the voltage.

How to obtain an accurate voltmeter reading if the meter pointer does not fall exactly on a scale mark

o You estimate between the divisions to your nearest guesstimate.

Compare the advantages and disadvantages of multimeters with single purpose meters

o A multimeter can be used for more than one instrument thus making it an economical instrument compared to a single purpose meter. Also, it is more versatile.

How the range of the voltmeter is determined

o It is determined in one of two ways. If the voltage is unknown, start the voltmeter at the highest range and work down until your measurement is in the middle third range of the meter, or place the range switch to the expected voltage setting for a known voltage.

The differences of the three readings taken on a battery

o If the batteries are old, they might start reading less voltage each time. If they are new, the voltage would be the same in all three readings.


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Name: ____________________________________ Class: ________ Date ___/___/___

Voltage and Its Measurement Lab Activity #2: Measure the Voltage Drop in a DC Circuit

Tools and Equipment


Power supply

Lamp or load

Switch

Procedure

1. Connect the power supply to the lamp or load as shown in the figure below.

2. Close the switch.

3. Connect the voltmeter across the power supply and adjust for 1 ½ volts. 4. Read and record the voltmeter indication. _________ 5. Connect the voltmeter across the lamp or load. 6. Read and record the voltmeter indication. _________ 7. Connect the voltmeter to the "+" terminal of the power supply and to the "+"

terminal of the lamp or load. 8. Read and record the voltmeter indication _________.


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Name: ____________________________________ Class: ________ Date ___/___/___ 9. With the switch still closed, measure and record the voltage across the switch.

__________ 10. With the voltmeter still connected to the switch, open the switch. 11. Read and record the voltmeter indication with the switch open. _________ 12. Return meter and materials to proper storage area.

Analysis

Note: Discuss and record the following in class.

The measurement across the lamp or load and across the source

The voltmeter reading across the closed switch

The voltmeter reading when the meter was connected to the "+" terminal of the power supply and the "+" terminal of the lamp or load

The difference of potential across the load and whether or not the voltage drop occurs across the lamp or load or the wire

The voltage reading across the open switch


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Voltage and Its Measurement Lab Activity #2: Measure the Voltage Drop in a DC Circuit Key

Tools and Equipment


Power supply

Lamp or load

Switch

Procedure

1. Connect the power supply to the lamp or load as shown in the figure below.

2. Close the switch. 3. Connect the voltmeter across the power supply and adjust for 1 ½ volts. 4. Read and record the voltmeter indication. 1.5 volts 5. Connect the voltmeter across the lamp or load. 6. Read and record the voltmeter indication. 1.5 volts 7. Connect the voltmeter to the “+” terminal of the power supply and to the “+”

terminal of the lamp or load. 8. Read and record the voltmeter indication. 0 volts


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9. With the switch still closed, measure and record the voltage across the switch.

0 volts 10. With the voltmeter still connected to the switch, open the switch. 11. Read and record the voltmeter indication with the switch open. 1.5 volts 12. Return meter and materials to proper storage area.

Analysis

Note: Discuss and record the following in class.

The measurement across the lamp or load and across the source

o Were the same, 1.5 volts

The voltmeter reading across the closed switch

o Since there is no load or resistance on a closed switch, it would measure 0 volts.

The voltmeter reading when the meter was connected to the "+" terminal of the power supply and the "+" terminal of the lamp or load

o Again, since there is no load or resistance on wire, it would measure 0 volts.

The difference of potential across the load and whether or not the voltage drop occurs across the lamp or load or the wire

o There is no load or very little resistance on wire or a closed switch; there is

no resultant potential. Thus, there is no voltage drop across these conductors.

The voltage reading across the open switch

o Since the switch is open, the lamp does not turn on and cause a voltage drop across the lamp. Therefore, the voltage on the positive side of the switch will be 1.5 volts. The voltage on the negative side will be 0 volts. The reading across the open switch will be 1.5 volts.


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Name: ____________________________________ Class: ________ Date ___/___/___

Voltage and Its Measurement Exam I

I. Match the terms with the correct definitions

1. Voltage A Instrument used to measure voltage 2. Volt B Electromotive force or pressure that causes the flow of electrical current 3. Voltage drop C The unit of measurement of electromotive force 4. Voltmeter D Difference in voltage measured across a component in a circuit

II. Match the symbols or abbreviations with their correct definition 5. Electromotive force A V 6. Voltmeter B E 7. Voltage source or applied voltage C EMF or emf 8. Voltage or voltage drop D VM

III. Match the symbols or abbreviations with their correct definition

9. Kilovolt A mV 10. Megavolt B µV 11. Millivolt C kV 12. Microvolt D MV

13. Which of the following is not a principal part of a voltmeter? A Connecting leads or probes B Volume control C Range switch D Voltage, current, resistance function switch


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14. Given the following closed loop circuit condition, the applied voltage is 32.5 volts, and the circuit of four loads with three loads having the following voltage drops (R1= 10.25v, R3= 5.75v and R4= 8.5v). What is the voltage drop across R2? A 9.5v B 5v C 8v D 12.75v

15. The following loads have voltage drops of R1= 13v, R2=5.5v, R3= 17.5v. What is the

voltage applied to this circuit? A 30.5v B 18.5v C 24v D 36v

16. Which of the following is not a principal part of a voltmeter?

A Light indicators B Multiple use scales C Direct current, alternating function switch D Connecting leads or probes

17. Who wrote the law of voltage?

A Kirchhoff B Watt C Einstein D Bell

18. Which of the following formulas is for voltage drops in a resistive circuit?

A Ea= VR1 – VR2 – VR3 - . . . - VRn B VR1 + VR2 + VR3 – E = 0 C VR1 – VR2 – VR3 + E = 1 D Ea = VR3 – VR2 + VR1

19. Which of the following statements is true about polarity in a resistive circuit?

A Negative to positive B End nearer negative of supply is positive C End nearer positive of supply is positive D Resultant potential across resistance


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20. Which of the following is not a common voltage source? A Batteries B Electronic power supplies C Photovoltaic D Generators/alternators

21. Which of the following symbols is not the prefix for a unit of voltage?

A K B M C V D m

22. Which of the following statements is true about current flow in a resistive circuit?

A End nearer negative of supply is positive B End nearer positive of supply is positive C Positive to negative D Resultant potential across resistance (voltage drop)

23. The following loads have voltage drops of R1= 3v, R2=5.5v, R3= 17.5v. What is the

voltage applied to this circuit? A 26v B 20.5v C 23v D 8.5v

24. Given the following closed loop circuit condition, the applied voltage is 34.5 volts,

and the circuit of four loads with three loads having the following voltage drops (R1= 10.25v, R2= 5.75v and R4= 8v). What is the voltage drop across R3? A 18v B 10.5v C 16v D 34.5v

25. Which of the following steps is the first step in the procedure for using a

voltmeter? A Assure that the meter will read expected voltage B Connect meter in parallel with load C Hold probes by insulated part D Set range switch for correct range


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Voltage and Its Measurement Exam I Key

I. Match the terms with the correct definitions

1. Voltage B A Instrument used to measure voltage 2. Volt C B Electromotive force or pressure that causes the flow of electrical current 3. Voltage drop D C The unit of measurement of electromotive force 4. Voltmeter A D Difference in voltage measured across a component in a circuit

II. Match the symbols or abbreviations with their correct definition 5. Electromotive force C A V 6. Voltmeter D B E 7. Voltage source or applied voltage B C EMF or emf 8. Voltage or voltage drop A D VM

III. Match the symbols or abbreviations with their correct definition

9. Kilovolt C A mV 10. Megavolt D B µV 11. Millivolt A C kV 12. Microvolt B D MV

13. Which of the following is not a principal part of a voltmeter? A Connecting leads or probes B Volume control C Range switch D Voltage, current, resistance function switch


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14. Given the following closed loop circuit condition, the applied voltage is 32.5 volts, and the circuit of four loads with three loads having the following voltage drops (R1= 10.25v, R3= 5.75v and R4= 8.5v). What is the voltage drop across R2? A 9.5v B 5v C 8v D 12.75v

15. The following loads have voltage drops of R1= 13v, R2=5.5v, R3= 17.5v. What is the voltage applied to this circuit? A 30.5v B 18.5v C 24v D 36v

16. Which of the following is not a principal part of a voltmeter? A Light indicators B Multiple use scales C Direct current, alternating function switch D Connecting leads or probes

17. Who wrote the law of voltage? A Kirchhoff B Watt C Einstein D Bell

18. Which of the following formulas is for voltage drops in a resistive circuit? A Ea= VR1 – VR2 – VR3 - . . . - VRn B VR1 + VR2 + VR3 – E = 0 C VR1 – VR2 – VR3 + E = 1 D Ea = VR3 – VR2 + VR1

19. Which of the following statements is true about polarity in a resistive circuit? A Negative to positive B End nearer negative of supply is positive C End nearer positive of supply is positive D Resultant potential across resistance


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20. Which of the following is not a common voltage source? A Batteries B Electronic power supplies C Photovoltaic D Generators/alternators

21. Which of the following symbols is not the prefix for a unit of voltage? A K B M C V D m

22. Which of the following statements is true about current flow in a resistive circuit? A End nearer negative of supply is positive B End nearer positive of supply is positive C Positive to negative D Resultant potential across resistance (voltage drop)

23. The following loads have voltage drops of R1= 3v, R2=5.5v, R3= 17.5v. What is the voltage applied to this circuit? A 26v B 20.5v C 23v D 8.5v

24. Given the following closed loop circuit condition, the applied voltage is 34.5 volts, and the circuit of four loads with three loads having the following voltage drops (R1= 10.25v, R2= 5.75v and R4= 8v). What is the voltage drop across R3? A 18v B 10.5v C 16v D 34.5v


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25. Which of the following steps is the first step in the procedure for using a voltmeter? A Assure that the meter will read expected voltage B Connect meter in parallel with load C Hold probes by insulated part D Set range switch for correct range


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Electrical Measurement Exam II

1. What is a voltage drop? A A battery that falls off a table B The difference between a battery’s rated voltage and its actual voltage C A difference in voltage measured across a component D A voltage that takes into account the age of the component

2. What does EMF stand for?

A Electrical Measurement oF B Electrical Measurement in Farads C Electromagnetic Function D Electromotive Force

3. What does DMM stand for? A Digital Multimeter B Digital Measurement Module C Decimal Meter Measurement D Digital Mobile Measurement 4. Which of the following statements is true for a voltage measurement?

A The circuit is not energized B The meter is part of the circuit C The meter is placed in series with the circuit D The circuit is energized

5. Which of the following statements is true for a resistance measurement?

A The circuit is not energized B The meter is part of the circuit C The meter is placed in series with the circuit D The circuit is energized

6. What is the most common problem that results from a current measurement?

A The leads burn up B A blown fuse C An out of range error D The battery goes dead

7. What law does a multimeter use for electrical measurement?

A Kirchhoff’s Law B The voltage drop law C Ohm’s Law D Newton’s Law


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8. Which of the following types of measurement can be made without ever having to remove a component lead from the circuit?

A Voltage B Current C Resistance D Continuity 9. What does V mean? A Volts DC B Volts AC C Current AC D Current DC 10. What does V mean? A Volts DC B Volts AC C Current AC D Current DC 11. What are the three most common electrical measurements? 12. List at least three other types of measurements a multimeter might be able to

make. 13. What happens if you measure across a component while the meter is in the

current measurement mode? 14. Give a summary of how to perform a voltage measurement.


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Electrical Measurement Exam II (key)

1. What is a voltage drop?

A A battery that falls off a table

B The difference between a battery’s rated voltage and its actual voltage

C A difference in voltage measured across a component

D A voltage that takes into account the age of the component

2. What does EMF stand for?

A Electrical Measurement oF

B Electrical Measurement in Farads

C Electromagnetic Function

D Electromotive Force

3. What does DMM stand for?

A Digital Multimeter

B Digital Measurement Module

C Decimal Meter Measurement

D Digital Mobile Measurement

4. Which of the following statements is true for a voltage measurement?

A The circuit is not energized

B The meter is part of the circuit

C The meter is placed in series with the circuit

D The circuit is energized

5. Which of the following statements is true for a resistance measurement?

A The circuit is not energized

B The meter is part of the circuit

C The meter is placed in series with the circuit

D The circuit is energized

6. What is the most common problem that results from a current measurement?

A The leads burn up

B A blown fuse

C An out of range error

D The battery goes dead


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7. What law does a multimeter use for electrical measurement?

A Kirchhoff’s Law

B The voltage drop law

C Ohm’s Law

D Newton’s Law

8. Which of the following types of measurement can be made without ever having

to remove a component lead from the circuit?

A Voltage

B Current

C Resistance

D Continuity

9. What does V mean?

A Volts DC

B Volts AC

C Current AC

D Current DC

10. What does V mean?

A Volts DC

B Volts AC

C Current AC

D Current DC

11. What are the three most common electrical measurements?

Voltage

Resistance

Current


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12. List at least three other types of measurements a multimeter might be able to

make.

Continuity

Diode test (also used for transistors)

Temperature

Capacitance

Frequency

13. What happens if you measure across a component while the meter is in the

current measurement mode?

The fuse will blow

14. Give a summary of how to perform a voltage measurement.

1. Select V~ (ac) or V (dc), as desired.

2. Plug the black test probe into the COM input jack. Plug the red test probe into

the V input jack.

3. If the DMM has manual ranging only, select the highest range so as not to

overload the input.

4. Touch the probe tips to the circuit across a load or power source (in parallel to

the circuit).

5. View the reading, being sure to note units.

model instruction plandata.cteunt.org/content/files/stem/electronics/unit-7... · ·...

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