LAB 2 DET10013

DET10013 - ELECTRICAL TECHNOLOGY

EXPERIMENT 2: SERIES AND PARALLEL CIRCUIT

1.0 LEARNING OUTCOMES
CLO 2: Construct DC circuit and measure related parameters using appropriate electric equipment.

2.0 OBJECTIVES
1. To construct series and parallel circuit.
2. To measure resistance, current and voltage in series and parallel circuits.
3. To analyse the characteristics of series and parallel circuits using ohm’s law.

3.0 EQUIPMENT unit

1. DC Power Supply 1
2. Resistors - 3.3K, 8.2K, 1K, 15K 1
3. Multimeter 1
4. Breadboard 1

4.0 THEORY
In an electrical circuit, resistor can be connected in series or parallel to current flows through them
as shown in Figure 2.1 and 2.2.
In series circuit, the current is the SAME for the entire resistor, but the voltage drops V1, V2, V3
across each resistor are DIFFERENCE depend on the value of the resistance R1, R2 and R3. The
total resistance ( RT ) three series resistor is given by equation:

RT = R1 + R2 + R3
IT = I1 = I2 = I3

VT = V1 + V2 + V3

Figure 2.1: Resistor in series
In parallel circuit, the voltage across each resistor is the SAME but the currents I1, I2, I3 through
each resistor are DIFFERENCE, depend on the value of the resistance R1, R2 and R3. The total
resistance ( RT ) of three parallel resistors can be determined from equation:

VT = V1 = V2 = V3
IT = I1 + I2 + I3

Figure 2.2: Resistor in parallel

5

DET10013 - ELECTRICAL TECHNOLOGY
5.0 PROCEDURE

5.1 Part A: Series Circuit

+_

Figure 2.3: Series Circuit
1. Calculate all the theory values and record the results in Table 2.1. Attach the calculation in

Discussion part.
2. Construct the circuit as shown in Figure 2.3.
3. Turn ON power supply. Set the power supply to 10V.
4. Measure voltage drop at each resistor and total current flow through in circuit as shown in Figure

2.4 and Figure 2.5.
5. Record all the results in Table 2.1

Figure 2.4 +

Figure 2.5

6

DET10013 - ELECTRICAL TECHNOLOGY
5.2 Part B : Parallel Circuit

15V 15 kΩ 8.2 kΩ 3.3 kΩ

Figure 2.6: Parallel Circuit

1. Calculate all the theory values and record the results in Table 2.2. Attach the calculation in
Discussion part.

2. Construct the circuit as shown in Figure 2.6.
3. Turn ON power supply. Set the power supply to 15V.
4. Measure the voltage drop at each resistor and current flow IT, I1, I2 and I3 as shown in Figure

2.7 and Figure 2.8.
5. Record all the results in Table 2.2.

+ + +

15V 15 k 8.2 k 3.3 k
V
V
V

Figure 2.7

+

mA

IT I1 I2 I3

A 8.2 k 3.3 k

15V 15 k + +

+ mA mA
A
mA

AA
Figure 2.8

7

DET10013 - ELECTRICAL TECHNOLOGY

6.0 RESULT
6.1 PART A: Series Circuit

Total Resistance (calculated) : ______________________
Total Resistance (measured) : _______________________

CURRENT Calculated Measured VOLTAGE Calculated Measured
(I) (mA) (mA) (V) (V) (V)
I1 V1
I2 V2 (9 marks)
I3 V3
IT VT

Table 2.1: Series Circuit

6.2 PART B: Parallel Circuit

Total Resistance (calculated) : ______________________

Total Resistance (measured) : _______________________

CURRENT Calculated Measured VOLTAGE Calculated Measured
(I) (mA) (mA) (V) (V) (V)
I1 V1 (9 marks)

I2 V2

I3 V3

IT VT

Table 2.2: Parallel Circuit

8

DET10013 - ELECTRICAL TECHNOLOGY

7.0 DISCUSSION & QUESTIONS

7.1 PART A: Series Circuit

1. Show calculation steps to get total resistance, currents and voltages in Table 2.1 (10 marks)

2. From the readings on Table 2.1, explain the relationship for these (4 marks)
i. the current flow through R1, R2 and R3 (I1, I2 and I3)
ii. the total current flow in the circuit (IT) and the current flow through R1, R2 and R3.
iii. the voltage drops V1, V2 and V3
iv. the supply voltage, VT with voltage drops, V1, V2 and V3

7.2 PART B: Parallel Circuit (10 marks)
(4 marks)
1. Show calculation steps to get total resistance, currents and voltages in Table 2.2

2. From the readings on Table 2.2, explain the relationship for these
i. the voltage drops, V1, V2 and V3
ii. the supply voltage, VT and the voltage drops, V1, V2 and V3
iii. the current flow through R1, R2 and R3 (I1, I2 and I3)
iv. the total current flow, (IT) with the current flow through R1, R2 and R3

8.0 CONCLUSION (5 marks)

9