An-Najah University
ELECTRICAL CIRCUITS LAB
Lab(10641215) Experiment #3
Created by
:
Adel Bani Jaber &Muhammad Nazzal
2020
Instructor Name: Dr.Omar Khaled Tamimi Course Name: ELECTRICAL CIRCUITS LAB
Time: Wednesday (2-5) . Date:12-2-2020.
Section: Electrical Engineering. Semster :second Semester 2020-2021.
Group Members: Adel Bni Jaber &Muhammad Nazzal.
* * * * * * NETWORK THEOREMS
*Introduction and Objectives *
in this course we studied about many interesting topics such as Kirchhoff’s laws,
mesh and nodal analysis, superposition principle, Thevenin’s theorem and more ,
but the more interesting is that in the current semester we are learning to apply
them practically to see how useful are they. In the previous weeks of the circuit lab
we were firstly introduced to the lab and its tools and then applied ohms law and
resistors -series and parallel connection by our hands and in this experiment we got
deeper to the circuits world. In this experiment we are going to talk about network
.theorems such as Kirchhoff’s laws, superposition principle and Thevenin’s theorem
**Tools and Equipment's
: the tools we used in this Exp are
digital multi-meter(DMM) ♦wires ♦
some clips ♦Power supply♦
training board. ♦different resistors♦
**************************************************
*Procedures*
##This report is divided into three main parts as the following:
1. Kirchhoff’s Law
2. Superposition Theorem
3. Thevenin’s Theorem
***********************************************************
1) Kirchhoff’s Law: In this experiment it was required to measure the
voltage across the resistors R1 to R5 shown in Figure 1: Kirchhoff’s Law
experiment setup. Then using Kirchhoff’s Law to verify the results
)2(
)1(
Figure-1
Collecting the required tools such as the power supply, the .1
.DMM,some conductive wires and some clipses
The resistors were connected with the power supply as shown in .2
.Figure 1
The voltage for each resistor was measured by connecting The .3
DMM-used as voltmeter- in parallel with each resistor and then
.reading the value from the screen of the DMM
The current for each resistor was measured by connecting The .4
DMM-used now as ammeter- in series after each resistor and then
.reading the value from the screen of the DMM
At the end all the values of the currents and the voltages for each .5
resistor were collected and put in Table-1 .In addition the theoretical
values of the currents and the voltages for each resistor were
.calculated using KCL and KVL and put in the same table
.The error percentage was also evaluated and put in the table .6
Resistance Voltage (V) Current (mA)
R1 11 2.350
R2 2.356 2.350
R3 1.644 0.730
R4 0.542 1.600
R5 1.101 1.600
Table 1
Calculations: using mesh analysis we calculate the current in each ##
:resistance
Loop (1): -15-I1*(4.7k+1k)-I2*2.2k=0 I2=I1-I3
7.9kI1-2.2kI3=-15 (1)
LOOP (2): -I3*(330+680)+I2*2.2k=0 I2=I1-I3
2.2kI1-3210kI3=0 (2)
:We solve this equation then the result will be
I1=2.346mA
I3=1.6mA
I2=0.746mA
These calculated currents are very close to the values of ###
the currents that we have found practically and are presented
in the above table
**************************************************
:Superposition Theorem )2
1. Connect the circuit as shown in the schematic of figure5 to the
training board.
)1( )2(
Figure 5
2. Measure each current (I1 , I2 and I3) and tabulate the results in Table 2.
3. Remove the 15V and replace it with short circuit as shown in figure 6.
)2(
)1(
Figure 6
4. Measure each current (I’1, I’2 and I’3) and tabulate the results in Table
2.
5. Remove the 10V and replace it with short circuit as shown in figure 7.
)1( )2(
Figure 7
6. Measure each current (I”1, I”2 and
I”3) and tabulate the results in Table 2 :
And the results have shown in Table 2:
Current (mA)
0.33- I1
-4.75 I2
4.42 I3
-2.24 I’1
-0.71 I’2
-1.53 I’3
1.90 I”1
-4.02 I”2
Table 2
5.94 I”3
From results it could figured out that the currents direction does not
always agrees with the currents in figure.
And it could figured out that there is are relationship between (I1 ,
I’1and I”1) which is I1 = I’1 + I”1 and the same relationship holds for
(I2 , I’2and I”2) and (I3 , I’3and I”3).
##Calculations:
For first circuit:
Loop1: 2.5kI1-2.2kI3=12 (1)
:Loop2
2.2kI1-3210I3=-15 (2)
:We solve this equation then the result will be
I1=-0.318mA
I3=4.454mA
I2=-4.772mA
For second circuit:
Loop1: 2.5kI1-2.2kI3=12 (1)
:Loop2
2.2kI1-3210I3=0 (2)
:We solve this equation then the result will be
I’1=-2.22mA
I’2=-0.7
I’3=-1.52mA
For third circuit:
Loop1: 2.5kI1-2.2kI3=0 (1)
:Loop2
2.2kI1-3210I3=-15 (2)
:We solve this equation then the result will be
I”1=1.9mA
I”2=-4.07mA
I”3=5.97mA
***********************************************************
:Thevenin’s Theorem )3
1. Connect the circuit as shown in the schematic of figure 8 to the
training board.
Figure 8
2. Measure the current in the
680Ω resistor.
3. Remove the 680Ω resistor and measure open circuit voltage which
indicates V th.
4.Connect the circuit as shown in the schematic of figure 9 to the
training board.
Figure 9
5.Measure the current by applying different voltages
(2V, 4V, 6V and 8V) and tabulate the results in Table 4.
I in 680Ω was 4.03 (mA).
Vth was 6.87 V
:And the results have shown in Table 4 and Figure##
Rth (Ohm) Itest (mA) Vtest (volt)
1041.66 1.92 2
1030.69 3.91 4.03 Table 4
1030.92 5.82 6
)=1033.53 Rth(average
and the 1030.88 7.77 8.01 (Ohm)
current calculated
4.05mA was =
.which is to measured value
**************************************************
*Conclusion*
In this experiment we have learned and understand three of
electrical network theorems (Kirchhoff’s Law Superposition
Principle and Thevenin’s Theorem) allow us to easily analyze
complex circuits and we had a good sense of linear circuits
properties and the theorems which can apply on this circuits.
