Curtin University of Technology
School of Electrical and Computer Engineering
Electrical
Systems
100 Laboratory
Expt No. 2 DC CIRCUITS
1
OBJECTIVE
To predict the performance of various electronic circuits and power networks requires
the engineer to
be
able to analyse the circuits and networks using a range
analysis
techniques.
A few of the fundamental analysis met
hods are investigated in this
l
aboratory
. This experiment introduces the basic concepts of dc circuit analysis using
Ohms and Kirchhoffs
Laws:
Ohms Law
Series Circuit
Parallel Circuit
Mesh Analysis
Nodal Analysis
2
APPARATUS
Dual DC Power Supply:
GP
C

3030
Digital Multimeter:
Fluke 175
Resistance:
1 x 100
,
1 x 120
,
2 x 150
,
1 x 470
,
1 x 820
,
1 x 1k
, 1 x 1.5
k
, 1 x 1
.8k
.
Br
ead Board
3
PRELIMINARY:
NOTE: You may need to consult you text,
research theory
in the library, o
r
the internet
before yo
u can complete the preliminary
. However by completing the preliminary
you will better understand the requirements of this laborator
y and be able to make
judgments on
the accuracy of
measured
results.
The preliminary is worth 25% of
your laboratory mark for each experiment.
3.1
Before coming to the laboratory neatly draw the circuit shown in Figure
2
.1
, 2.2 2.3
and 2.4 in your
log boo
k.
3.2
Calculate for Figure 2.1 the voltage acros
s each resistor,
the current through each
resistor as well as the voltage at points 1, 2, 3, & 4 with reference to ground GND.
Tabulate
the
results, leaving
space in
the
table
,
to enter the measured values
,
so
that
a comparison
can
be made between
the
theoretical and practical results
Electrical
Systems
100
Laboratory 2
__________________________________________________
____________________________
Version
4
February
200
6
2
3.3
Calculate for Figure 2.2 the vo
ltage across each resistor
, voltage across terminal
AB
,
the current through each resistor
and the total current drawn from the supply.
Tabulate th
e results, leaving
space in
the
table
,
to enter the measured values
,
so that
a comparison
can
be made between
the
t
heoretical and practical result
.
3.4
Calculate for Figure 2.3 the voltage across each resistor, voltage across terminal CE,
the current through
each resistor and the total current drawn from the supply.
Tabulate the results, leaving
space in
the
table
,
to enter the measured values
,
so that
a comparison
can
be made between
the
t
heoretical and practical result.
3.5
D
evelop the matrix equations for the
network
shown in Figure 2.4
using Kirchoff’s
Law methods of Maxwell’ Mesh Analysis and Nodal Analysis.
Analyse
the circuit
using each of the
methods
to find the voltage across each resistor, the current
through each resistor a
nd the voltage at points
A,
B, C, D and E
with respect to
ground (GND).
Tabulate the results, leaving
space in
the
table
,
to enter the
measured values
,
so that a comparison
can
be made between
the
theoretical and
practical results
.
Show all equ
ations and calculations for the
analys
is in
the
log book in a clear
and logical manner.
A logbook containing the answers to the preliminary questions will be marked by
the laboratory supervisor during the laboratory session.
4
LABORATORY:
4.1
Parallel
Circuit
4.1.1
After setting the DC power supply c
ontrol to independent, adjust the current
limit for both supply
A
&
B
to 300mA
(as in experiment 1)
.
Remember to change the position of the red
plug in lead on the
multimeter into the
400
mA socket, and to place the ammeter
in series with the
componen
t
.
(Set Ammeter to DC mode)
FIGURE 2.1
4.1.2
Connect the circuit, as shown in Figure
2
.
2
, using the dual power supply
output
A
.
Let
R
1
= 1
k
,
R
2
=
1.5 k
,
R
3
=
1.8 k
,
and
E
1
=
20 V
Electrical
Systems
100
Laboratory 2
__________________________________________________
____________________________
Version
4
February
200
6
3
4.1.3
Using
the Digital Multimeter measure the required measurement listed below.
Make sure to note the polarity of the voltage across each element and the
measured current direction.
The voltage across each re
sistor;
The current through each resistor;
The total current drawn from the supply.
4.1.4
Show
using measured results
that Kirchhoff's
C
urrent
L
aw holds for
Figure 2.1
.
4.2
Open Circuit I
FIGURE 2.
2
4.2.1
Connect the circuit, as shown in Figure
2
.
2
, using the dual p
ower supply
output
s
A
.
Let
R
1
= 1
50
,
R
2
=
150
.
4.2.2
Using the Digital Multimeter measure:
The voltage across each resistor;
The current through each resistor;
The voltage across V
AB
.
4.2.3
Show
using measured results
that Kirchhoff's
Voltage
L
aw holds for
Figure 2.2
.
Figure 2.3
4.3
Open Circuit
II
4.3.1
Connect the circuit, as shown in Figure
2
.
3
, using the dual power supply
outputs
A
.
Let
R
1
= 1
50
,
R
2
=
150
,
R
3
=
820
,
and
R
4
=
100
and
E
1
=
15
V
.
4.3.2
Using the Digital Multimeter measure:
Electrical
Systems
100
Laboratory 2
__________________________________________________
____________________________
Version
4
February
200
6
4
The voltage across each resistor;
The c
urrent through each resistor;
The voltage across V
CE
.
4.3.3
Using
Kirchhoff's
Voltage
L
aw
, shows that the result V
BE
is equal to V
CE
.
Figure 2.
4
4.4
DC
Crcuits and N
etworks
4.4.1
Connect the circuit, as shown in Figure
2
.
4
, using the dual power supply
outputs
A
.
Let
R
1
= 1
50
,
R
2
=
150
,
R
3
=
820
,
R
4
=
100
,
R
5
=
470
,
R
6
=
120
,
E
1
=
15
V
and
E
2
=
20
V.
4.4.2
Using the Digital Multimeter measure:
4.4.2.1
The voltage across each resistor;
4.4.2.2
The current through each resistor;
4.4.2.3
The vol
ta
ge at points A, B, C & D
with reference to GND.
All answers to preliminary questions and recorded experimental results should be
recorded in a logbook for inspection at the end of semester
5
R
EPORT TO INCLUDE
:
5.1
The answers to the following questions sho
uld be included in any laboratory report
discussion section.
5.1.1
C
omparison
tables
of measured and theoretical results
on a
results page
.
5.1.2
P
ossible sources of error that may exist between calculated and measured values.
A short form report
in an A4 folder must
be
handed to
the
laboratory supervisor
for marking at your next laboratory session.
End of Experiment
DISK:
CURTIN
DIR:
ELECTRICAL
SYSTEMS
100
FILE:
LAB
2

200
6v4
.D0C
AUTH:
N.D.KAYE
DATE:
FEBRUARY
200
6
FOR SEMESTER
1
& 2
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