EXPERIMENT 2
Series and Parallel connections of the Linear Resistance
INTRODUCTION:
Series and Parallel are connection that we can observe in a circuit. If a circuit is connected in series
is known as series circuit; same as, the parallel circuits which are connected completely in parallel.
And also in a series circuits, the current in all the subject in circuits are same and its voltage is
equal to the total sum of all the voltage drop. However in Parallel circuits, the voltage of each and
all subject is same and thus its current is equal to the sum of the entire subject flowing in the
circuits.
Objectives:
1. To study the properties of resistors, voltages and currents in series and in parallel connection.
2. To determine experimentally and by computation the total resistance of a series and parallelconnected resistor.
3. Compute and measure the total resistance of a combined series- parallel connected resistance.
Procedure:
SERIES Circuit:
1. Connect the circuit as shown in Figure 1. Set the DC supply to 10Vdc.
(R1 = 1 kΩ , R2 = 2 kΩ, R3 = 100Ω, R4 = 4.7 kΩ)
2. Measure and record voltage across Eae, Eab, Ebc, Ecd, Ead, Ebe and currents I in Table 1.
3. Disconnect the DC supply and using a VOM. Measure the resistance across a and e.
4. Compute for the total resistance using Ohm’s Law.
5. Using nominal values of the resistance and the source voltage, compute the expected voltages and
current in the circuit.
6. Compute for the percent difference between the measured and computed values of the voltages
and currents. Use computed values as the correct values.
Figure 1
PARALLEL Circuit:
1. Connect the circuit as shown in Figure 2. Set the power supply to 10Vdc.
(R1 = 1 kΩ , R2 = 2 kΩ, R3 = 100Ω, R4 = 4.7 kΩ)
2. Measure and record EAB, I1, I2, I3, I4, and It in Table 2.
3. Disconnect the DC supply and using a VOM. Measure the resistance across A and B.
4. Compute for the total resistance using Ohm’s Law.
5. Using nominal values of the resistance and the source voltage, compute the expected voltages and
current in the circuit.
6. Compute for the percent difference between the measured and computed values of the voltages
and currents.
Figure 2
SERIES – PARALLEL Circuit:
1. Connect the circuit as shown in Figure 3. Set the power supply to 10Vdc.
(R1 = 1 kΩ , R2 = 2 kΩ, R3 = 100Ω, R4 = 4.7 kΩ, R5 = 15 kΩ)
2. Measure and record It, IR2, IR3, IR4, ER4, Ecd and ER5 in Table 3.
3. Turn off the power supply and disconnect it from the circuit. Using a VOM, measure the
resistance across a and b.
4. Compute for the total resistance using Ohm’s Law.
5. Using nominal values of the resistance and the source voltage, compute the expected voltages and
current in the circuit.
6. Compute for the percent difference between the measured and computed values of the voltages
and currents.
Figure 3
PRESENTATION and DISCUSSION of RESULTS
Include the following question in the discussion of results:
1. What is the value of the resistance of an open circuit?
2. What is the value of the resistance of a short circuit?
Table 1. Series Circuit
Measured Values
Computed Values
% Difference
Eae (V)
10
Eab (V)
0.128
Ebc (V)
6.025
Ecd (V)
1.282
Ebe (V)
9.872
Ead (V)
7.434
I (mA)
1.28
Rae (kΩ)
7.8
10
.0128
6.025
1.282
9.872
7.434
1.28
7.8
0
0
0
0
0
0
0
0
Table 2. Parallel Circuit
Measured Values
Computed Values
% Difference
EAB (V)
10
I1 (mA)
2.13
I2 (mA)
5
I3 (mA)
10
I4 (mA)
100
It (mA)
117.128
Rae (kΩ)
0.0854
10
2.13
5
10
100
117.128
0.0854
0
0
0
0
0
0
0
Table 3. Series- Parallel Circuit
Measured Values
Computed Values
% Difference
ER4 (V)
2.38
Ecd (V)
0.044
ER5 (V)
7.58
IR1 (mA)
0.439
IR3 (mA)
0.439
IR2 (mA)
0.022
I (mA)
.505
Rae (kΩ)
19.787
2.38
0.044
7.58
0.439
0.439
0.022
0.505
19.789
0
0
0
0
0
0
0
0
3. Compare your measured values with your calculated values. Is there an agreement between the
two values? Explain your answer.
 Yes, there is given that the measured values and computed values are equal if not this
app is unreliable at all.
CONCLUSION:
 In case of visualization app is reliable for me because, I know how hard to
visualize a given problem. But in case of getting its value I recommend the
computation since it is consist of process by process formulation backed up by the
well-known mathematicians/scientist.
 For me it is easier to compute for series connection knowing that for some aspect
the only operation we’ll use is addition unlike in parallel there is such fraction. but
all in all series-parallel connection is much harder that those two itself, because
before getting its complete answer it first required us to simplify then solve by
series method which makes it more complicated.
References