be.01.10 series_parallel resistive circuits instructor lab

8/4/2019 BE.01.10 Series_Parallel Resistive Circuits Instructor Lab

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UNITED STATES MARINE CORPSMARINE CORPS COMMUNICATION-ELECTRONICS SCHOOL

TRAINING COMMANDBOX 788251

TWENTYNINE PALMS, CALIFORNIA 92278

INSTRUCTOR LAB HANDOUT

SERIES / PARALLEL RESISTIVE CIRCUITS

BE.01.10

BASIC ELECTRONICS COURSE

M092721

REVISED 08/15/2008

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TERMINAL LEARNING OBJECTIVES:

1. Provided cables, connectors, Test Measurement andDiagnostic Equipment, tools and a unit under test; testground electronics equipment, per the references. (2800-

ACT-1303)

2. Given a faulty electronic device, Test Measurement andDiagnostic Equipment and tools, diagnose basic electroniccircuits, per the references. (2800-ACT-1305)

ENABLING LEARNING OBJECTIVES:

1. Without the aid of references, select the statement thatidentifies a characteristic of DC power in a series/parallel

resistive circuit configuration, per the references. (2800-ACT-

1305bf)

2. Without the aid of references, select the statement thatidentifies the characteristics of a series/parallel resistive

circuit, per the references. (2800-ACT-1303s)

3. Without the aid of references, given a series/parallelresistive circuit schematic and specified parameters, select the

statement that identifies the unknown circuit parameter, per the

references. (2800-ACT-1303q)

4. Without the aid of references, given a series/parallel

resistive electronic DC circuit, Test Measurement and DiagnosticEquipment (TMDE), and references, connect the TMDE to the

circuit to be tested, per the references. (2800-ACT-1303b)

5. Without the aid of references, given a series/parallelresistive test circuit, Test Measurement and Diagnostic

Equipment (TMDE), and references, adjust the TMDE to display a

recorded measurement, per the references. (2800-ACT-1303c)

6. Without the aid of references, given a series/parallelresistive DC test circuit, Test Measurement and Diagnostic

Equipment (TMDE), and references, record specified circuit

parameters, per the references. (2800-ACT-1303d)

STUDENT INFORMATION:

1. Ensure that you have the primary references and Student

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Handout SH BE.01

2. You will be responsible for the learning objectives.Ensure that you understand all the information contained inthe Student Handout. This will be accomplished by studyingyour notes, reading the references, and completing the

assigned homework. The learning objectives will be testedby the BE.01 Performance Examination and the BE.01 WrittenExamination.

3. Complete the practical application portion of this handout.

4. If you need extra help, ask!

STUDENT HANDOUT PRESENTATION:

During this lab you will be using the DC FUNDAMENTALS BOARD also

known as board 1

I. RESISTANCE IN A SERIES/PARALLEL RESISTIVE CIRCUIT:

A. Ensure that the Base Unit Power Source is turned on.Ensure that the DC FUNDAMENTALS Circuit Board isinserted into the base unit. Do no connect the PowerSupply to the circuit at this time.

B. B. Locate the SERIES/PARALLEL CIRCUIT block (refer toFigure 10-01).

Figure 10-01C. Setup the multimeter to measure resistance. Measure

and record the resistive values listed by placing thetest leads across the indicated components.

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1. R1 = _330 _____

2. R2 = _1.2k ____

3. R3 = _2.4k ____

D. Remove the Ohmmeter from the circuit. Insert two (2)two-post connectors into the two-post test pointsabove R2 and R3. Measure and record the equivalentresistance (REQ) of the parallel configuration of R2||R3by placing the red test lead into the test point thatis closest to the top of one of the resistors and theblack test lead into the test point that is closest tothe bottom of one of the resistors.

4. REQ = _800 _____

E. Measure and record the total circuit resistance byplacing the red test lead into the test point closestto the top of R1 and the black test lead into the testpoint closest to the bottom of either R2 or R3.

5. RT = _1.183k __

F. Remove the two-post connectors from the circuit.Click on the right arrow to advance to the nextscreen. You will notice that the CM light has turned

on which indicates that CM-12 has been activated. Usethe Ohmmeter to measure and record the indicatedresistive values.

6. R1 = _330 _____

7. R2 = _831 _____

8. R3 = _2.4k ____

G. Remove the Ohmmeter from the circuit. Insert two (2)

two-post connectors into the two-post test pointsabove R2 and R3. Measure and record the equivalentresistance (REQ) of the parallel configuration of R2||R3as before.

9. REQ = _617.17 __

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H. Measure and record the total circuit resistance asbefore.

10. RT = _937 _____

11. Which resistor has been changed?

R1 / R2 / R3

12. Did the value of this component increase ordecrease?

Increase / Decrease

I. Click on the right arrow to advance to the nextscreen. Note that the CM light has turned on whichindicates that CM-13 has been activated. Remove thetwo (2) two-post connectors from the circuit. Measureand record the indicated resistive values.

13. R1 = _1.33k ___

14. R2 = _1.2k ____

15. R3 = _2.4k ____

J. Remove the Ohmmeter from the circuit. Insert two (2)two-post connectors into the two-post test pointsabove R2 and R3. Measure and record the indicatedresistive values.

16. REQ = _800 _____

17. RT = _2.112k __

18. Which component changed from its original

measured value?

R1 / R2 / R3

19. Did the value of that component increase ordecrease?

Increase / Decrease

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Click on the right arrow to advance to the review questions.

Answer these questions on the screen as well as in this Lab

Workbook.

1. A series/parallel resistive circuit is __________.

a. made up of series and parallel componentsconnected together

b. a group of series circuits and parallel circuitsconnected together

c. made up of series and parallel circuits connectedtogether

d. all of the above

2. To find total resistance in a series/parallelresistive circuit, reduce the __________.

a. parallel resistances to an equivalent value and

add it to the value of the series components

b. series components to an equivalent value and add

it to the resistors in the parallel branches.

c. parallel resistances to an equivalent value anduse the product-over-the-sum method with theseries resistors

d. series resistors to an equivalent value and usethe reciprocal method with the series components

3. What would cause the actual measured value of totalcircuit resistance to vary from the calculated value?

a. The tolerance of the multimeter

b. The tolerance of the circuit components.

c. An uncalibrated Ohmmeter.

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d. All of the above

4. If three 10k resistors were connected together toform a series/parallel circuit, the total resistanceof the circuit would be __________.

a. 30k

b. 15k

c. 10k

d. 5k

5. If total resistance increased by 226 and R1 in theSERIES/PARALLEL CIRCUIT depicted here remained thesame, the change in the circuit which caused this is__________.

a. a 200 resistor was placed inseries with R2

b. a 770 resistor was placed inseries with R1

c.a 4.7k

resistor was placedin series with R3

d. a 7k resistor was added to the parallel branch

II. VOLTAGE IN A SERIES/PARALLEL RESISTIVE CIRCUIT:

A. Setup the multimeter to measure DC Voltage. Locate

the SERIES/PARALLEL Circuit Block and insert a two-post connector into the two-post test points betweenthe top of the power supply and R1. Insert two (2)two-post connectors into the two-post test points atthe bottom of R1 between R2 and R3. Measure and recordthe indicated voltage drops (observe polarity).

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1. VR1 = _4.38VDC__

2.VR2 = _10.62VDC_

3. VR3 = _10.62VDC_

4. VA = _15VDC____

5. Does the applied voltage equal the value of theVR1 + (VR2||VR3)?

Yes / No

B. Click on the right arrow to advance to the nextscreen. Note that the CM light has turned onindicating that CM-12 has been activated. Measure andrecord the indicated values.

6. VR1 = _5.23VDC__

7. VR2 = _9.77VDC__

8. VR3 = _9.77VDC__

9. VA = _15VDC____

C. Click on the right arrow to advance to the nextscreen. Note that the CM light is on, indicating thatCM-13 has been activated. Measure and record theindicated voltage values.

10. VR1 = _9.34VDC__

11. VR2 = _5.66VDC__

12. VR3 = _5.66VDC__

13. VA = _15VDC____

14. Based on the voltage measurements taken, whichcomponents resistive value has changed?

R1 / R2 / R3

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15. Did the value of that component increase or

decrease?

Increase / Decrease



Workbook.

1. Which variation of the Ohms law equation isused to find voltage in a circuit?

a. E = I/R

b. E = IR

c. E = R/I

d. E = E/RI

2. In a series/parallel circuit consisting of

three equal 5k resistors, the voltage drop is__________.

a. greatest across the parallel branches

b. greatest across the series resistors

c. equal across all components

d. none of the above

3. What information is needed to calculate thevoltage drop across the parallel branch of aseries/parallel circuit?

a. Total circuit current and equivalent

resistance

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b. Equivalent resistance

c. Applied voltage

d. None of the above4. For the depicted circuit the effect on thecircuit if R3 were shorted would be __________.

a. VR1decreasing

b. VR2increasing

c. VREQ

increasing

d. VR1equaling VA

5. On the SERIES/PARALLEL CIRCUIT BLOCK, if RTdecreased by 183 and R1 stayed the same, themodification that was made to the circuit would haveto be __________.

a. A

600 resistorwas placed inseries with R1

b. A 1kresistor wasplaced inparallel with R1

c. A

2.7k resistor

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was placed in parallel with R2

d. A 4.7k resistor was placed inparallel with R3

III. CURRENT IN A SERIES/PARALLEL RESISTIVE CIRCUIT:

A. Make sure that there is nothing plugged into thecircuit at this time. Setup the multimeter to measureDC Voltage. Measure and record the applied voltage byplacing the red test lead into the test point that isclosest to the bottom of the power supply (observepolarity), and the black test lead into the test pointclosest to the top of the power supply.

1. VA = _15VDC____

B. Remove the Voltmeter from the circuit and configure itto measure DC Current. Insert a two-post connectorinto the two-post test points between the top of thepower supply and resistor R1. Insert a second two-post

connector into the two-post test points between thebottom or R1 and the top of R3. Measure and record thebranch current flowing through R2 by inserting the testleads into the two-post test points at the junctionbetween R2 and R1.

2. IR2 = _8.85mA___

C. Remove the Ammeter from the circuit and replace itwith a two post connector. Remove the two-postconnector from the two-post test points between the

bottom or R1 and the top of R3. Insert the Ammeterleads into these test points (observe polarity).Measure and record the current flowing through R3.

3. IR3 = _4.43mA___

D. Remove the test leads from the circuit and replacethem with a two-post connector. Remove the two-post

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connector from the top of the power supply and insertthe test leads into this location. Measure and recordtotal current flowing through the circuit.

4. IT = _13.28mA__

1. Did total current equal the sum of the branchcurrents?

Yes / No

E. Click on the right arrow to advance to the nextscreen. Note that the CM light has turned onindicating that CM-12 has been activated. Measure andrecord total current flowing through the circuit now.

6. IT = _15.83mA__

F. Remove the test leads from the circuit and replacethem with a two-post connector. Remove the two-postconnector from the two-post test points between thebottom of R1 and the top of R2. Replace it with thetest leads (observe polarity). Measure and record thecurrent flowing through R2.

7. IR2 = _11.76mA__

G. Remove the test leads from the circuit and replacethem with a two-post connector. Remove the two-postconnector from the two-post test points between R1 andR3 and replace it with the test leads (observepolarity). Measure and record the current flowingthrough R3.

8. IR3 = _4.07mA___

9. Does IT still equal the sum of all branchcurrents, despite the change in total current?

Yes / No

H. Click on the right arrow to advance to the nextscreen. Notice that the CM light has turned on againindicating that CM-13 has become activated. Measureand record the current flowing through R3 at this time.

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10. IR3 = _2.35mA___

I. Remove the test leads from the circuit and replacethem with a two-post connector. Remove the two-postconnector from the two-post test points between R1 and

R2 and replace it with the test leads (observepolarity). Measure and record the current flowingthrough R2 at this time.

11. IR2 = _4.7mA____

J. Remove the test leads from the circuit and replacethem with a two-post connector. Remove the two-postconnector from the top of the power supply and insertthe test leads into this location (observe polarity).Measure and record total current flowing through thecircuit.

12. IT = _7.05mA___



Workbook.

1. Current flow in a series/parallel circuit __________.

a. is determined by the total circuit resistance and

applied voltage

b. is determined by the resistors in each parallelbranch

c. divides in each series circuit

d. equals the sum of the current in eachcircuit component

2. In a series/parallel resistive circuit, what wouldcause one branch of the parallel portion of thecircuit to have a lower current flowing through itthan another branch in the same circuit?

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a. a higher resistance.

b. a lower resistance.

c. an increase in current in one leg.

d. all branches have equal current flow.

3. In the circuit depicted here, if R3 were shorted ITwould __________.

a. remain the same

b. decrease

c. increase

d. not flow

4. In the circuit depicted here, if R2 were openIT would __________.

a. remain the same

b. increase

c. decrease

d. vary

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5. In the circuit depicted here, if RT decreased by 800the cause of the modification would be __________.

a. a 10 resistor beingplaced in parallelwith R3

b. a 1K resistor beingplaced in series withR1

c. R3 shorting

d. R2 opening

IV. POWER IN A SERIES/PARALLEL CIRCUIT:

A. Locate the SERIES/PARALLEL CIRCUIT Block (refer toFigure 10-01). Remove the test leads and all two-postconnectors from the circuit. Setup the multimeter tomeasure resistance. Measure and record the indicatedresistances by following the same procedures as before.

1. R1 = _330 _____

2. R2 = _1.2k ____

3. R3 = _2.4k ____

B. Insert two (2) two-post connectors into the two-post

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test points between R2 and R3. Measure and record theequivalent resistance of the two parallel branches.

4. REQ = _800 _____

C. Reinsert the test leads in the circuit so that totalresistance can be measured. Record the value of RT inthe space provided.

5. RT = _1.13k ___

D. Remove the test leads from the circuit and reconfigurethe multimeter to measure DC Voltage. Insert a two-post connector into the two-post test points at thetop of the power supply so that the circuit can beenergized. Measure and record the indicated voltages.

6. VA = _15VDC____

7. VR1 = _4.35VDC__

8. VR2 = _10.65VDC_

9. VR3 = _10.65VDC_

E. Using the measured values of resistance and voltagejust taken, calculate the indicated power dissipation.

10. PR1 = _57.34mW__

11. PR2 = _94.52mW__

12. PR3 = _47.26mW__

13. PT = _199.1mW__

F. Setup the multimeter to measure DC Current. Removethe two-post connector from the two-post test pointsat the top of the power supply. Measure and record

total current flowing through the circuit.

14. IT = _13.28mA__

G. Using the measured value of total current and theapplied voltage, calculate the total power dissipatedin this series/parallel circuit.

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15. PT = _199.1mW__

16. Did the total power calculated by using themeasured values of IT and VA equal the sum of thepower dissipation found by taking the sum of the

individual component values?

Yes / No

H. Remove the test leads and all two-post connectors fromthe circuit. There are no review questions for thissection, continue on to the next section.

V. POWER DISSIPATION:

A. Locate the POWER CIRCUIT Block (refer to Figure 10-02).R1 in the circuit is going to be viewed as the internalresistance of the power source. Resistors R2 and R3together are going to be viewed as the load for thiscircuit. Place switch S1 into position A.

Figure 10-02

B. Insert two (2) two-post connectors into the two-post test

points above resistors R2 and R3. Setup the multi-meter to measure resistance. Measure and record totalcircuit resistance by placing the red test lead intothe test point closest to the left of R1 and the blacktest lead into the test point closest to the bottom orR2 and R3.

17. RT = _2K ______

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C. Remove the Ohmmeter from the circuit and set it up tomeasure DC Voltage. Insert a two-post connector intothe two-post test points closest to the top of thepower supply. Measure and record the applied voltage

in this circuit by placing the red test lead into thetest point closest to the bottom of the power supplyand the black test lead into the test point closest tothe top of the power supply (observe polarity).

18. VA = _15VDC____D. Measure and record the voltage drop across the load by

placing the red test lead into the test point closestto the right side of R1 and the black test lead intothe test point closest to the bottom of resistors R2and R3.

19. VRL = _7.5VDC___

E. Remove the Voltmeter from the circuit and configure itto measure DC Current. Remove the two-post connectorfrom the two-post test points at the top of the powersupply and replace it with the test leads (observepolarity) in order to measure total current.

20. IT = _7.5mA____

F. Using the measured values and the variations of the

power equation, calculate the indicated power values.

21. PT = _112.5mW__

22. PR1 = _56.25mW__

23. PRL = _56.25mW__

G. Remove R3 from the circuit by removing the two-postconnector from the top of that branch. Setup themultimeter to measure resistance. Measure and record

total circuit resistance as before.

24. RT = _3K ______

H. Remove the Ohmmeter from the circuit and set it up tomeasure DC Voltage. Insert a two-post connector intothe two-post test points above the power supply.Measure and record the indicated values as before.

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25. VA = _15VDC____

26. VRL = _10VDC____

I. Remove the Voltmeter from the circuit and reconfigureit to measure DC Current. Remove the two-postconnector from the top of the power supply and replaceit with the test leads (observe polarity). Measureand record total circuit current.

27. IT = _5mA______

J. Using the values you just took; calculate theindicated power dissipation of the indicatedcomponents.

28. PT = _75mW_____

29. PR1 = _25mW_____

30. PRL = _50mW_____

K. Click on the right arrow to advance to the nextscreen. Note that the CM has turned on whichindicates that CM-16 has been activated. Setup themultimeter to measure resistance. Re-add R3 into thecircuit by reinserting a two-post connector into the

two-post test points above that resistor. Measure andrecord total circuit resistance.

31. RT = _1.5k _____

L. Remove the Ohmmeter from the circuit and set it up tomeasure DC Voltage. Insert a two-post connector intothe two-post test point at the top of the powersupply. Measure and record the indicated voltages asbefore.

32. VA = _15VDC____

33. VRL = _5VDC_____

M. Remove the Voltmeter from the circuit and reconfigureit to measure DC Current. Remove the two-postconnector from the top of the power supply and replaceit with the test leads (observe polarity). Measure

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and record total circuit current.

34. IT = _10mA_____

N. Analyze the three groups of readings. Perform all

necessary calculations and complete the chartfollowing. Use the three groups of readings that wereobtained starting with question #17 in this section tocomplete the chart.

RT ( ) RL ( ) IL (mA) V L (VDC) P RL(mW)1.5k 500 10mA 5VDC 50mW

2k 1k 7.5mA 7.5VDC 56.25mW

3k 2k 5mA 10VDC 50mW

35. Based on the chart, which load condition providesthe most output power?

a. When RL is less than the internal resistance

b. When RL is equal to the internal resistance

c. When RL is greater than the internalresistance



Workbook.

1. The total power in a series/parallel circuit is__________.

a. determined by the total circuit resistance

b. determined by the resistors in each parallelbranch

c. determined by the resistors in each series portion

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d. equal to the sum of the power dissipated in eachparallel branch

2. The total power in a series/parallel circuit with avoltage source of 30VDC, a current of 20mA in theseries components, and a current of 10mA in each ofthe two parallel branches is __________.

a. 1.5W

b. 1.2W

c. 900mW

d. 600mW

3. To determine total power in a three branch parallelcircuit, __________.

a. use the product-over-the-sum method

b. add individual branch powers

c. use the formula P = E/R

d. multiply the equivalent resistance by the appliedvoltage

4. On the POWER CIRCUIT Block, total resistance increases

by 470 and total powerdissipated equals 91.05mW.Which of the followingconditions would causethis?

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R1

R4

+


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a. A 240 resistor is added in series with R1.

b. A 240 resistor is added in parallel with R1.

c. A 470 resistor is added in series with R4.

d. A 470 resistor is added in parallel with R4.5. Based on the chart you completed at the end of

exercise 5, maximum power is transferred to the loadwhen __________.

a. load voltage is greater than the voltage drop ofthe internal resistance

b. load voltage is equal to the voltage drop of the

internal resistance

c. load voltage is less than the voltage drop of theinternal resistance

d. the voltage of the internal resistor is greaterthan load voltage

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CONCLUSIONS:

1. All rules for series circuits will beused for the series portions of a series/parallel circuit.

2. All rules for parallel circuits will beused for the parallel portions of a series/parallel circuit.

3. Total resistance is equal to the sum ofall series resistors plus the equivalent resistances.

4. Total current flows through seriescomponents in a series parallel circuit.

5. Total current is divided amongst allbranch resistors.

6. Total power is additive in all circuits.

7. Maximum power transfer occurs when loadresistance equals source resistance.

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REFERENCES:

2. Operator Manual: Fluke 77/BN3. Basic Electronics (9th Edition)4. Introductory Electric Circuits, Robert T. Paynter5. WinFACET, Lab-Volt Systems Inc.

PREPARED BY: ____________________________________________

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TITLE: __________________________________________________SIGNATURE: ________________________ DATE: ______________MODIFIED BY: _P.A.DEDEAUX__________ DATE: _07/10/2007___APPROVED BY: ____________________________________________TITLE: __________________________________________________

SIGNATURE: ________________________ DATE: ______________

be.01.10 series_parallel resistive circuits instructor lab

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