Name:
Alle.v\
.. rt
Grade: _ _ _ _ __
Lab #2
Basic Circuit Laws: Ohm's Law and Kirchhoffs Laws
1.0 Purpose
In this lab, you will experimentally validate Ohm's law, Kirchhoff's voltage law (KVL) and Kirchhoff's current law
(KCL).
Before Starting this lab you should know:
123456-
The basic definition of voltage, current, resistance and power.
How to use the DMM to measure the voltage according to its polarities(+) and(-).
How to use the DMM to measure the current according to its direction.
How to read the four bands resistor code and measure the resistance using the DMM.
How to calculate the power using measured voltage, current and resistance.
How to connect elements in series and in parallel using breadboard .
Upon completion of this lab, you will learn:
1- How to experimentally validate Ohm's law, Kirchhoff's voltage law, and Kirchhoff's current law.
2- How to apply Ohm's law, KCL and KVL to solve for circuit problems
3- How to determine the number of meshes, nodes and branches in a circuit
4- How to plot experimental data using Matlab
5- How to do DC sweep using LTSPICE.
6- How to carry voltage, current and resistance measurements using DMMs
Introduction to Circu its Laboratory: Lab #2: Basic Circuits La ws. EECS, WSU, Ah med Abu-Hajar, Ph.D. (January 2020)
l l P ag e
2.0 Prelab {30 points)
]
out of 30
Prelab Grade:
Read th e Lab handout mat eri al, watch ass igned Videos, and then an swer the following question s and do LTSPICE
Simul ation : (30 points)
1- Ohm's Law is ex pressed as V = JR . Explain this 1-V relationship in words and support your answe r with a
drawing of a resistor that shows the direction of the current and polarities of the voltage . (3 points)
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O~IM' s
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+: lov,\~
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+\,._, el.e.,l).A.."'-"r
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> c,.,...., 0
1> ro p:i ..---ha "'-'-'\ -\-() 4-.1\.....
v-o.+•0
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c,. ~ , .,._
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pc+t..,,{, ... I
e, lcoh-1.c. \
(
\o..,., pok"' -he..\ /
tA,~ Ir.
If the voltage across the l.SkO resistor was found to be -2.2SV, what would the current through the
resistor according to Ohm's law be? (2 points).
3-
Ohm ' s law states that v (t ) = i(t)R. If the resistor is held unchange-d, prove that~ = '!!. R
dt
points)
dV.(+)
~-
di·(-t)
<t
+
.R
dv
cH
c),
-}
o"\"
4-
= R . (3
dt
Jv
Q
d -t
dt
°'
Jv
~\
-::
Define a node in electric circuit. (2 points)
lS
, ,.....
5- Define a loop and a mesh in electric circuit. (2 point s)
A
lco,p
I\
o.. po-+\,,.
1v.
S e...-•c.1 \,,.~1---.. V'trt' +\M,-,
\/1. 0
\v. s• rh.
1+ •
c. c ,..i:.. .... t t-
l....
0
wl.-c..v1..
e.\A.,v7 +\. 1""'
-t\...,.. f,_--1-1.,.) •
A
Introduction to Ci rcuits Laboratory : l ab #2: Basic Circuits Law s. EECS, WSU, Ahm ed Abu-Hajar, Ph .D. (January 2020)
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2
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e
6- For the circuit in Figure 3 of thi s handout (page 7), how many branches, nodes, loops, meshes does it
have? (2 points)
Numb er of Branches=
Numb er of Nodes =1!
Number of Loops=
Number of Meshes =
S
f Lt
X-z
7- For the circuit in Figure 3 of this handout (page 7), write the KVL equation for all the meshes in term of
the voltage V, to Vs(3 points)
kVL
loo\"' '.l
-V 5 1.
4,':\IA
-\.
- 11.{v -+
G..C\k
O
o
I
1
4-
1.."l~
(r:-i · .I""L J
1.1 + 1.?.L...•11 -
:.
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,.-z.~ 1?.:. C9
I-1 -1..-i..kt"-- 11.\V::
:lCSlL.." I1.. 4V -l 1..1.k •(I 4 -11.)
0
8- Write the KCL equations at each of the nodes including the ground node . (3 points)
v-k>+
(Q
2.1.1....n
Grade: ..... ...
/q····
out of 20
9- LTSPICE: Use DC sweep analysis to simulate the circuit of Figure 1 (in this handout) by varying the DC
voltage source from -10 V to 10 V with a step size of 0.1. Then plot the resistor' s current vs. its voltage.
Print a hardcopy of the results. Bring the hardcopy to lab and show it to your TA as part of the pre-lab
Demo. Attach the hardcopy of the graph with your report submission. (S points)
10- LTSPICE: Using bias points simulation, simulate the circuit of Figure 3. Show the simulated values of the
voltage and current markers. Print a hardcopy of the results . Bring the hardcopy to lab and show it to your
TA as part of the pre-lab Demo. Attach th e hardcopy of the graph with your report submission . (5 poi nts)
PICE simulation is used to compare your experimental generated graph with the theoret ical simu lated
5... . .......... out of 10
J:, covr<:Jtl- Reii-.s~ u1,i tJ.N~
Lrtft;;_o" ";':;:';';"o
",!;~')1;:c_<·';;;f:,"f \ ~Ii:' ""' ~ o ~ " ~t
---------- Demo LTSPICE simulation to the TA and have him initialize it.
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Grade: ...
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3.0 Experiment #1 Validating Ohm's Law (25 points)
Exp. 1 Grade:
............... .........
out of 25
In thi s experiment you will validate Ohm's Law by building a single resistor circuit of Figure 1. The circuit contains
a programmable ~C power supply, two DMMs, breadboard and a 10 k!l resistor. Ohm 's law will be va lidated by
varying the voltage from -10 V to 10 V and measuring the current through the resistor.
+
DC
V
Power
Supply
l1
R,
10 kD
Figure 1 Basic single resistor circuit.
3.1 Procedure {20 points)
1.
Using the 5% tolerance resistor color code, determine the 4 color band for the 10 kO .
ListcolorcodeforRl=lOkO:
2.
\o,..-,.,...,.. -
1.,[.,_CA,\. •
0 ..-...
lo-.-.,....., •\:, l ...... . .,.,._~ ·,,t.
')"Ld
Using the DMM, measure the value of Rl resistor and recode it in the following table
Name
Nominal
R,
10 kO
Measured
3.
Connect the circuit shown in Figurel on your breadboard. Make sure the (-) polarity of the DC power
4.
supply is connected to the ground.
To measure the voltage and current of the resistor simultaneously, connect DMMl and DMM2 in the
circuit as shown in Figure 2.
I.
DMMl is used to measure the voltage across the resistor, same as the power supply.
II.
DMM2 is used to measure the current through re sistor.
DC
+
Power
Supply
Figure 2 Measuring voltage and the curren t across the resistor simultaneously.
Introduction t o Circuits Laboratory: Lab #2: Basic Circuits Laws . EECS, WSU, Ahmed Abu -Hajar, Ph.D . (J anuary 2020)
4 1P ar.e
5. Vary the DC power supply from Oto 10 V, and record the DMMs measurements in the table shown below.
Make sure that the power supply maximum current is set at 100 mA. Using the DMMs measured values,
calculate R, the change in voltage (I\V) and the change in the current (Ill) for each of the two consecutive
values. Then calculate the slope IIV/111.
Power
DMMl
Supply
V(Volt)
R=V/1
I\V
ill
(kO)
(Volt)
(mA)
ilV/ill
V/mA (kO)
-
-
-
-
ov
0
+lV
1.<91Hfv $-'1~ :I.•111. "1,'l:ll5"
+2V
l,.Cll'.'h'
a,, t~l'-1'11 q,
+3V
J,c,11';\fV
<9.l6ll1'1 "1'
+4V
'i, ClllHV ~.4041,(9
+SV
5,C,ct.°IV (Sl.'!dl.,
+6V
0
qr?i
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~:l(lt.l.L(
Cf. ql)I
1.Cl>~ll
(l).-j,<P:l
q ,"IHCI
(SI, 1,C,IP'r
'l,'11(9$
't'ti=J
't,ql/"I
Q,
1.&~'- C,.1$1,
)c;
'i,'113'-1
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C..~~v (9,<.,SC'tla
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q, q~q)
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'i,'ICSl'it
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,.~To.I
+SV
CZ ,tW-'i ~ (!l.'SC!~tcso
+9V
'f, Cl Cl '?V (9 .'I l9'1&~ '{,10l ~:i
q ,qi),'!
i~.(tC,f\f l.~1
G,10'.l~
q,'ll~
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+7V
+lOV
6.
DMM21
(mA)
'l, 01:51 :1.
"' 't()~ 'l.
q,'ii'"l'>~
'L C\<:oe-=!
Reverse the polarities of the power DC power supply on the breadboard. Now, you are applying a negative
voltage across the resistor. Keep the rest of the circuit unchanged. Vary the DC power supply from Oto
-10 V. Record the DMMs measurements in the table shown below. Calculate R, the change in voltage (ilV)
and the change in the current (Ill) for each of the two consecutive values. Then calculate the slope IIV/111.
Power
Supply
OV
DMMl
V(Volt)
0
DMM21
(mA)
0
-lV
-1,6l~~'IV ·(11,:Mlll l
-2V
-2, ~Cli b'
-3V
• 1,<ll\'11.;4, • (II, ~&ll'
-4V
-SV
-6V
'i,©Cl('ov
- (9 .t~t~I
. -~'ifi
· S,C>&lV -19.'l~ll
(.,$ C,~V
-(3l.'
I!)
(kO)
ilV
(Volt)
ill
(mA)
ilV/111
V/mA (kO)
-
-
-
-
R=V/1
ct, q H.3
- '3
'\,'11\1
-1..~(1)1,J
-9V
• 'I. ~9".o - ~-'l(g'IS'
1,&,Blib~
i~lt q ,Q11'I
o..~'1 -f'b
r.i 'f • q (l:J(I - ~- 'J'l,<S
-8V
-l0V
(9.
q .'l'l, l l
C\ ,Q'.l 1"'l
q, I\ 'Jl.~
- ~- 't'l.'T~ -di, 1~,
II\. 'l11 I/ -1.. ~~(b C, -~.1&.1& C\, 'IC9=i'l
<>i. 'i Cl),, -'1,Gl<llj.C - (S), 1311 c:i.icin
-1.(!)~ 1 , -6l,'l&ll 'I' q&r."i
_ (SI ,q lll'M.1 'l.9~
·'U$'1
-7V
,(l)Qli;""J . (51.'l~j
ct. 'U1-"I
• 1,Clll'l.~ -&-1.0n 'I., "l~"i1
_(S) , q'I~()
- 1, (P~1,(g
- 1.CP:Hi ii t\. '8'11,~ - -t.~IHISI
-~,,_~
ey , i'b~~
q ,-,,;~G
-1,'llll
'I, 'ln."i'
-.1~
Introdu ction to Circuits Laboratory : Lab #2: Basic Circuits Laws. EECS, WSU , Ahmed Abu-Hajar, Ph.D. (January 2020)
S f P age
7.
Plot the measured 1-V curve from steps 4 &5 using Matlab. Combine the measured data from -lOV to +lOV
·
tal
in Matlab, and attach a printed hard copy of the graph to the handout. Compare your Matlab expenmen
data plot to your LTSPICE Results.
~Demo the circuit, your measurements and Matlab plot to the TA and has him initialize it.
8. From step 6, what is the relationship between the resistor's voltage and current?
9. From step 6, what did happen to the current's value when the voltage across the resistor was negative?
10. From the measured values of the Tables in steps 4 & 5 what can you say about the calculated slope
(/'J.V/1:i.l)?
Slo~
\..v.,..>
3.2 Conclusion (5 points)
Using clear, eligible and proper English, type a single paragraph using Microsoft Word that describes your
co nclusion of the experiment. Attach the typed conclusion to the handout.
Note: The conclusion is a paragraph that is made of 5-10 sentences and it should contain at least:
1234-
One sentence to state the purpose of the experiments
One sentence to describe the experiments
One sentence to discuss the results of the experiment
One se ntence gives a conclusion or a solid statement about the experiment. Must state the error in
% to validate your solid conclusion.
You should use third person style. Passive voice is encouraged over using " I", but if you have to then use
"we" instead of " I". Basically. you should not use " I" or " we".
Introd uction to Circuits Laboratory: Lab #2: Basic Circuits Laws. EECS, WSU, Ahmed Abu -Hajar, Ph.D. (January 2020)
6 1 Page
4.0 Experiment #2 Validating Kirchhoff's Current and Voltage Laws (25 Points)
I
EXP,2 Grade: ............. ..... out of
In t his experim ent, you w ill valid at e Kirchhoff's current law (KCL) and Kirchhoff's voltage law (KVL) by buildin g the
circuit of Figure 3. The ci rcuit is made of two DC power supplies and three resistors. You will need two DMM s.
On e DMM w ill be used to meas ure th e DC voltage in V across ewlement and the other DMM w ill be used to
m easure th e current in mA through each element.
-=-----
\ / _
8)
.!J..... R1=4.7kQ
~ /3
\ .,.~...,i;...;.-1\A,/\,"--'--.
DC Power
DC Power
Supplyl
Supply2
(Vsi = 14 V)
(V, 2 =7V)
'i'
Figure 3: Resistive circuit with two DC power supplies .
4.1 Procedure (20 points)
1.
Using the 5% tolerance resistor color code, determine the color for the 10 kO, 4.7 kO and 2.2 kO .
Color Code for 10 kO :
Color Code for 4.7 kO:
Color Code for 2.2 kO :
2.
3.
1-ro
bl&cA...
1,;""
.,tt..__...
,-&.~
c)'r-.Y\\-"(.
v , .l..,.-t
':>•I
re:;.}
re..~
,ed
,.
"!I"' I~
Using DMM , m easure the values for the 2.2 kO, 10 kO and 4.7 kO resistors . Then recode them in the
following table .
Name
Nominal
R,
4.7 kO
R,
2.2k0
R,
10 kO
Measured
1.-t,t-,-ic.1.<. SL
-.. 'l".lC..'-1 k .n_
'i . "r{<;cu~.n.
Conn ect the circuit of Figure 3 and then program DC Power Supply 1 to be 14 V and DC Power Supply 2 to
be 7 V. Follow provided diagram. Set the power supply maximum current to 100 mA.
1•,i·,
V,i= +14 V
V,,= 7 V
;1---------------- 1
------7
i
L - - _ ______ _ _ _ _ :_ _______ _ __ ___ _I
Int roduct ion to Circu its Labo ratory : Lab #2 : Basic Ci rcuits LalNiNijECS, WSU, Ahmed Abu -Hajar, Ph. D. (January 2020)
7 1Pa c e
25
4. Usin g DMMl, mea sure th e DC voltage in V across each element and record the measured values in the
foll owi ng table.
v,,
V,
(Volt)
(Volt)
l"\.G.Gt l q . 1cr~v
v,
v,,
V3
(Volt)
(Volt)
(Volt)
11. t:nv , . ".l'i'~lj\ C ,q(tq V
5. Using DMM2, measure the DC current in mA of each branch and then record the measured values in the
following table. The direction of each current is specified by its arrow. Validate your measurements with
LTSP ICE Simulation.
1,,
(mA)
,i.~'\Lj
I,
lz
(mA)
(mA)
1.C\C\ l
13
(mA)
,.1.'13
ls2
(mA)
- ell, 'l.2<5l
& .·:n,&
6. Using the measured valu.es of step 4, validate KVL equation for each loop.
kVL
!
"1, I.\.•
2:: V::. (51
(bCll
'3
+ C\ • :1.
°)
:: ©
L.
G.qci.q
7. Using the measured values of step 5, validate KCL equation at each node (including the ground node).
~.1..1.cs
"5-:t -
,..,..._
li2..
....
-
= )
•
'2,,
£.'.l.1
-
1.'.l°t½ - ~.,"lQI
=
(9
o the circuit, your measurements and your KCL and KVL equations to the TA and have him
r "cipation Grade: Graded by the TA and have him initialize it (20 points) :
z;:>120
Participation Grade: ........ ...... out of 20
Introductio n to Circuits l aboratory: Lab #2: Basic Circuits Laws. EECS, WSU, Ahmed Abu-Hajar, Ph.D. (January 2020)
Bl
P age
8.
Using th e measured data of Step 4 & Step 5, calculate the power of each element. Assume the absorbing
power is positive and the supplying power is negative. Validate your answer with LTSPICE Simulation.
Supply 1
(mW)
R1
(mW)
R2
(mW)
-3&>.,3'-/ H,11 C.
'1~ ,'6l
R3
(mW)
~.u.:J'\
Supply 2
(mW)
-1.,c., '-I ~
4.2 Conclusion (S points)
Using clear, eligible and proper English, type a single paragraph using Microsoft Word that describes your
conclusion of the experiment. Attach the typed conclusion to the handout.
Note: The conclusion is a paragraph that is made of 5-10 sentences and it should contain at least:
1- One sentence to state the purpose of the experiments
2- One sentence to describe the experiments
3- One sentence to discuss the results of the experiment
4- One sentence gives a conclusion or a solid statement about the experiment. Must state the error
in % to validate your solid conclusion.
You should use third person style. Passive voice is· encouraged over using "I", but if you have to then use
"we" instead of " I" . Basically, you should not use " I" or "we".
Final Grade:
Prelab (30 pts)
Experiment 1 (25 pts)
Experiment 2 (25 pts)
Participation (20 pts)
Total Grade
Introduction to Ci rcuits Laboratory: Lab h2: Basic Circuits Laws. EECS, WSU , Ahmed Ab u-Hajar, Ph .D. (January 20 20)
~I P,, r. e