EXPERIMENT NO. 1: PARALLEL AND SERIES CONNECTION OF LINEAR RESISTORS
1.1.
EXERCISE TITLE: RESISTANCE IN A SERIES RESISTIVE CURRENT
OBJECTIVES: 1. To determine the total resistance of a series resistive circuit 2. To verify the results with a multimeter. multimeter .
EQUIPMENT REQUIRED: 1- F.A.C.E.T. Base Unit 1- DC FUNDAMENTALS Circuit Board 2- 15 Vdc Power Supply 1- Multimeter
PROCEDURE: 1. Turn off the power sources. Insert the DC FUNDAMENTALS circuit board into the base unit. Do not turn on the power sources at this time. 2. Locate the SERIES CIRCUIT, circuit block of the DC FUNDAMENTALS circuit board. Record the color code of R 1, R2, and R3.
BAND 1
BAND 2
BAND3
R1
BROWN
BLACK
RED
R2
BROWN
RED
RED
R3
BLUE
RED
BROWN
3. Record the values of R1, R2, and R3. R1 = 10x10^2
Ω
R2 = 10x10^2 Ω R3 = 62x10 Ω
4. Calculate RT for the series circuit (R T = R+ R2+ R3). RT = 2820 Ω
5. Measure the record the values of R 1, R2, R3 and RT to ensure that the two post connectors is not in place. (See Figure 2.1-2). Your post readings will vary based on the tolerance of each component. R1 = .99k Ω
R2 = 1.81k
R3 = .62k Ω
Ω
RT = 2.792k Ω
Figure 2.1-2
6. Place CM switch 1 in the on position. Measure and record the values of R 1, R2, R3, and RT. R1 = 497
Ω
R2 = 1176 Ω
R3 = 622 Ω RT = 2295 Ω
7. Which resistors changed and by how much? What is the total circuit resistance? R1 = 501 Ω , RT = 2295 Ω
8. Place CM switch 1 in the OFF position. Place CM switch 2 in the ON position. Measure and record the values of R 1, R2, R3, and RT. R1 = 9910 Ω R2 = 1178 Ω R3 = 1249 Ω RT = 3417 Ω 9. Compare the values recorded instep 8 to those recorded in step 5. Which resistor changed and by how much? What is the total circuit resistance?
R3 = 629 Ω , RT = 3417 Ω
10. Place the CM switch 2 in the OFF position. Remove all circuit connection from the DC FUNDAMENTALS circuit board.
CONCLUSION:
We conclude that in order to determine the equivalent resistance in a series resistive circuit we must know the value of each resistors and the equivalent resistance that can be computed as the summation of the resistance present in the circuit or R E = ∑ R.
We conclude that in order to verify the values that we’ve got by reading the band present in each resistor we used the multimeter to determine their actual value.
We can also conclude that there are resistor present in each switches (CM) resulting for us to get different values of resistor when different switches was on.
1.2.
EXERCISE TITLE: RESISTANCE IN A PARALLEL RESISTIVE CIRCUIT
OBJECTIVES: 1. To determine the equivalent resistance in a parallel resistive circuit. 2. To verify the result with a multimeter.
EQUIPMENT REQUIRED: 1- F.A.C.E.T. Base Unit 1- DC FUNDAMENTALS 2- 15 Vdc Power Supply 1- Multimeter
PROCEDURES: 1. Insert the DC FUNDAMENTALS circuit board in the case unit. Do not apply power to the base unit. 2. Using the resistor color code, record the values of R 1, R2, and R3 in the PARALLEL CIRCUIT circuit block. R1 = 10x10^4
Ω
R2 = 22x10^2 R3 = 57x10^2 Ω
3. Measure the record the values of R 1, R2, and R3. NOTE:
Make
individual
resistance
measurements
without
two-post
connectors in place.
R1 = 9870 Ω R2 = 2147 Ω R3 = 4620 Ω 4. Connect the circuit shown in Figure 2.2-3. Note the placementof the two-post connection. Calculate the equivalent resistace (RE) in the parallel circuit consisting of R1 and R2 by using the product-over-sum method. RE = 1763.41
Ω
5. Measure and record R E. Verify that your measured value is the same as your calculated value. RE = 1763 Ω
6. Place CM switch 6 in the ON position. Measure and record the value of R 1, R2, and RE. NOTE: Add or remove two-post connectors as required to measure R 1 and R 2.
R1 = 9860 Ω R2 = 2571 Ω RE = 2040 Ω 7. Did R1 and R2 increase, decrease, or remain the same? R1 remains the almost the same. R2 increases.
8. How did the change in the circuit affect the equivalent resistance? RE increased.
9. Is the equivalent resistance less than the lowest resistor value in either branch? Yes.
10. Place CM switch 6 in the OFF position, then correct the circuit shown in Figure 2.2-4.
Figure 2.2-4.
11. When more than two resistors are in a parallel circuit, use the reciprocal method to find R E. Calculate R E. RE = 1276.27
Ω
12. Confirm your calculation by measuring and recording R E. Your calculated and measured values may not be equal but should be nearly the same. RE = 1277 Ω 13. Place CM switch 5 in the ON position. Measure and record R E, R1, R2, R3. RE = 922 Ω R1 = 2488 Ω R2 = 2417 Ω R3 = 4620 Ω 14. One resistance value (not including R E) has changed. Which one, and has it increased or decreased? R1 decreased.
15. How did this change affect the equivalent resistance of the circuit (measured in step 13)? RE decreased in value.
16. Is the equivalent less than the lowest resistor value of any branch? Yes.
17. Place CM switch 5 in the OFF position. Do not remove the circuit board connections. The F.A.C.E.T. setup will be used for a review question.
CONCLUSIONS:
We conclude that in order to determine
the equivalent resistance in a
parallel resistive circuit we must know the value of each resistor and the equivalent resistance (R E) can be connected as 1/R E = ∑ 1/RE
We can recheck it our (connected) computed R E correct by using multimeter.
We also conclude that the value of R E must be less than the lowest value of the resistor in the circuit.
1.3.
EXERCISE TITLE: RESISTANCE IN A SERIES-PARALLEL RESISTIVE CIRCUIT
OBJECTIVES: 1. To find the value of the total resistance in a series-parallel resistive circuit by using Ohm’s law. 2. To verify the results with a multimeter.
EQUIPMENT REQUIRED: 1- F.A.C.E.T Base Unit 1- DC FUNDAMENTALS Circuit Board 2- 15 Vdc Power Supply 1- Multimeter
PROCEDURES: 1. Insert the DC FUNDAMENTALS circuit board into the base unit. Do not turn the power sources. 2. Locate the SERIES/PARALLEL CIRCUIT circuit block, and connect the circuit shown in Figure 2.3-5.
Figure 2.3-5 NOTE: Do not apply power to the SERIES/PARALLEL CIRCUIT circuit block. 3. Calculate and record R E for the parallel branch circuit.
RE = 800 Ω
4. Calculate and record R T for the series/parallel circuit.
R T = 1120 Ω
5. Measure and record RE for the parallel branch circuit.
RE = 791 Ω
6. Measure and record RT.
RE = 1119 Ω
7. When more than two resistors are in a parallel branch, the reciprocal method is used to find R E. Calculate RE and RT for the circuit in Figure 2.3-6. RE = 617Ω , RT = 942.14Ω
Figure 2.3-6
8. The circuit shown in Figure 2.3-5 is the basic series/parallel circuit. The circuit is Figure 2.3-6 has an additional resistor, R 4 that you can add by closing CM Switch 12. Place CM switch 12 in the ON position. Measure and record the values of R E and RT. RE = 662Ω , RT = 990Ω 9. Does adding more resistance in parallel increase or decrease the total circuit resistance of a series/parallel circuit? It decreases.
10. Place CM switch 12 in the OFF position. 11. Place CM switch 13 in the ON position. Record the values of R 1 and RE. R1= 1300Ω , RE = 800Ω 12. Which resistor value changed, and did it increase or it decrease? R1 increased.
13. Was this changed due to resistance added in series or in parallel? In series or In parallel.
14. Calculate the new value of R T.
RT = 2510 Ω
15. Confirm your estimated value of R T by measuring. Is it correct? Yes.
16. Place CM switch 13 in the OFF position. 17. Place CM switch 15 in the ON position. Record the values of R 1 and RE. R1 = 323Ω , RE = 1181Ω 18. Which resistance value changed, and did it increased or decreased? R1 increased.
19. Was this changed due to resistance added in series, in parallel or neither? If neither, was there an open or was there a short across parallel branch? Yes, in series.
20. What will be the new value of R T?
RT = 1504Ω
21. Confirm you estimated value of R T by measuring, is it correct? Yes, we get 1505.
22. Place CM switch 15 in the OFF position, but do not disconnect your circuit. The F.A.C.E.T. setup will be used for a review question.
