İzmir University of Economics
EEE201 Electrical Circuits I
Title of the Experiment
Experiment – 3: Kirchhoff's Current Law
Name-Surname of the Student
Student Number
Due Date
17.10.2014
E-Mail
Submission Date
Instructor: Prof. Dr. Cüneyt GÜZELİŞ
Research Assistant: İbrahim Halil
ÖZCAN
Grade for the Lab (To be filled in by the instructor.)
Task
Pre-Lab Task 1
In-Lab Task 1
In-Lab Task 2
In-Lab Task 3
In-Lab Task 4
In-Lab Task 5
In-Lab Task 6
In-Lab Task 7
Total
Score
Pre-Lab Task 1
Consider the circuit given in Figure 1.
Gaussian
Surface - I
1
2 I3
I1
IS
R1
VS
3
R3
I2
R2
I4
R4
4
Figure 1. A four node circuit consisting of five circuit elements
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Write down Kirchoff's Current Law equations for all nodes. Then, obtain a matrix
representation for this equation system.
By applying Gauss-Jordan elimination procedure on the matrix obtained above, find a set
of independent currents and also a set of dependent currents.
Propose a way of measuring all of the currents by ammeter with a minimum number of
current measurements.
Obtain the KCL equation for the Gaussian Surface – I in terms of the KCL node
equations.
Explain whether or not the KCL equations for the nodes of the circuit are sufficient to
write all KCL equations from this circuit.
Implementation of Pre-Lab Task 1
In-Lab Task 1
Build the below circuit on the protoboard available in Yıldırım Electronics Basic Training Set Y-0016.
Choose the resistance values as R1 = R2 = R3 = R4 = 100 ohm. Adjust the power supply as Vs = 5
Volts.
1
IS
VS
2 I3
I1
R1
I2
R2
3
R3
I4
R4
4
In-Lab Task 2
Choose a set of independent currents. Then, measure the independent currents by an ammeter and
calculate the remaining (dependent) currents by KCL node equations.
Table 1
Independent
Currents
(Measured)
Dependent
Currents
(Calculated)
In-Lab Task 3
Now, measure the dependent currents by using ammeter and check whether or not they are
identical to the ones found by calculation in In-Lab Task 2.
Table 2
Dependent
Currents
(Calculated)
Dependent
Currents
(Measured)
In-Lab Task 4
Calculate the I2 / I3 and I2 / I1 ratios from the values measured in In-Lab Task 2 and Task 3.
Table 3
I2 / I3
I2 / I1
In-Lab Task 5
Repeat the measurements and calculations in Tasks 2 and 3 for another pair of independent and
dependent current sets.
Table 4
Independent
Currents
(Measured)
Dependent
Currents
(Calculated)
Dependent
Currents
(Measured)
In-Lab Task 6
Assume that I2 and I4 currents can be measured in a direct way whereas IS, I1 and I3 currents
cannot be. (Such situations may arise in circuits where a part of the circuit elements could not be
reachable due to long distances among circuit elements or due to some other limits.) For R 1 = R2 =
R3 = R4 = 100 ohm but with Vs = 2.5 Volts, measure I2 and I4 currents and then calculate IS, I1 and
I3 currents by choosing appropriate Gaussian surfaces. (Do not use more than one KCL equation in
each current calculation.)
Table 5
Measured Currents
Calculated Currents
I2 =
IS =
I1 =
I4 =
I3 =
In-Lab Task 7
Calculate the I2 / I3 and I2 / I1 ratios from the values measured in In-Lab Task 6 and compare them
to the ones obtained in In-Lab Task 4. Discuss your observations.
Table 6
I2 / I3
I2 / I1
Implementation of In-Lab Task 7
Discussion:
Student’s Evaluation of Learning Outcomes (Write in the following box what you have gained
from doing the Experiment 3.)

The knowledge of ...

The skill of measuring/computing/calculating/determining/finding/simulating of...

The awareness/consciousness of...