# Electrical circuits lab (3)

```ELECTRICAL CIRCUITS (1)
LAB (3)
SERIES RESISTANCE
OBJECTIVES
 Determine the total resistance of series DC circuit using an
ohmmeter or an application of Ohm’s law.
 Calculate the total resistance of series DC circuit and note the effect
of the relative magnitude of each series resistor on the total
resistance.
 Learn to identify which of a network are in series.
 Develop additional confidence in the use of DMM ohmmeter section
LAB EQUIPMENT
 Power supply.
 220-Ω, 330-Ω,1-KΩ(1/4-W)Resistors.
 100-Ω (1/4-W)*3
 DMM.
 Wires
PART (1)
TWO SERIES RESISTORS
a) Construct the circuit shown
b) Calculate the total resistance using measured values
𝑅𝑇 = 𝑅1 + 𝑅2 + 𝑅3
c) Measure the total resistance using DMM and calculate %D
d) Set the supply to 8 V and measure the current
e) Calculate the total resistance using the supply voltage an ammeter
RT
How does the results of this part and part (c) compare?
𝑅1 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅2 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
R1
220Ω
R2
100Ω
PART (2)
THREE SERIES RESISTORS
a) Construct the circuit shown
𝑅1 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅2 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅3 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
b) Calculate the total resistance using measured values
𝑅𝑇 = 𝑅1 + 𝑅2 + 𝑅3
c) Measure the total resistance using DMM and calculate %D
d) Set the supply to 8 V and measure the current
e) Calculate the total resistance using the supply voltage an
How does the results of this part and part (c) compare?
RT
R1
R2
R3
100Ω
220Ω
330Ω
PART (3)
FIVE SERIES RESISTORS
a) Construct the circuit shown
b) Calculate the total resistance using measured values
𝑅𝑇 = 𝑅1 + 𝑅2 + 𝑅3 + 𝑅4 + 𝑅5
c) Measure the total resistance using DMM and calculate %D
d) Set the supply to 8 V and measure the current
𝑅1 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑
𝑅2 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑
𝑅3 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑
𝑅4 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑
𝑅5 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑
e) Calculate the total resistance using the supply voltage an
How does the results of this part and part (c) compare?
= ‫ـــــــــــــــــــــــــ‬
= ‫ـــــــــــــــــــــــــ‬
= ‫ـــــــــــــــــــــــــ‬
= ‫ـــــــــــــــــــــــــ‬
= ‫ـــــــــــــــــــــــــ‬
R1
R2
R3
220Ω
100Ω
100Ω
R4
1kΩ
RT
R5
330Ω
PART (4)
DIFFERENT LEVELS OF RESISTANCE
a) Construct the circuit shown
b) Calculate the total resistance using measured values
= 𝑅1 + 𝑅2 + 𝑅3 + 𝑅4 + 𝑅5
𝑅𝑇
𝑅1 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅2 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅3 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
c) Measure the total resistance using DMM
d) Calculate the total resistance using measured values if 𝑅1 is ignored
and using DMM measure the total resistance and calculate %D
between this measured and the measures in part (c)
R1
R2
e) Repeat (c) and (d) if both 𝑅1 and 𝑅2 is ignored.
f)
220Ω
Set the supply to 10 V and measure the current
g) Calculate the total resistance using the supply voltage an ammeter
RT
1kΩ
R3
100kΩ
1
PART (5)
𝑅1 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅2 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅3 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
a) Construct the circuit shown
b) Calculate the total resistance using measured values
c) Measure the total resistance using DMM and calculate %D
R1
d) Calculate the difference percent between measured value of
part (c) and calculated value of part (b)
220Ω
What was the impact of 𝑅3 resistor on the total resistance?
RT
R2
330Ω
R3
1kΩ
10
PART (6)
a) Construct the circuit shown
b) Calculate the total resistance using measured values
𝑅1 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅2 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
𝑅3 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 = ‫ـــــــــــــــــــــــــ‬
c) Measure the total resistance using DMM and calculate %D
R1
d) Calculate the difference percent between measured value of
part (c) and calculated value of part (b)
What was the impact of 𝑅3 resistor on the total resistance?
220Ω
R3
RT
R2
330Ω
1kΩ
1
PROBLEMS
Thank you
```