UNIVERSITI TEKNOLOGI MARA FAKULTI KEJURUTERAAN KIMIA
CHEMISTRY LABORATORY
(CHE 175)
Remarks :
NoTitleAllocated Marks (%)Marks (%)
1.Abstract/Summary5
2.Introduction5
3.Aims/Objective5
4.Theory5
5.Procedure3
6.Apparatus5
7.Results20
8.Calculations10
9.Discussions20
10.Conclusions10
11.Recommendations5
12.References5
13.Appendices2
Total100
Checked by : Rechecked by :
SUMMARY
EXPERIMENT 6B: RESISTANCES IN CIRCUITS
This experiment was done by the objectives to determine the
resistance in circuits. This experiment is done with six resistors
where three of them have the same value and three other have the
different value. And according to the result, when the resistors
are connected in series, the current passes through each resistor
will be same and the total voltage, V is equal to the sum of the
voltages across each resistor V=V1+V2+V3. The total resistance is
the sum of the separate resistances, Req=R1+R2+R3The resistors also
can be connecting in parallel then the current from the source
splits into separate branches, I=I1+I2+I3. But in parallel it has
the same voltage across it. In parallel connection, the resistance
is less than each single resistance and the equation are
Req=1/R1+1/R2+R3.EXPERIMENT 6C: VOLTAGES IN CIRCUITS
This experiment was done to measure the voltages in three
different circuits which is in series, parallel n combination
connection. In series connection, when the resistors are connected
together, the total voltage, V is equal to the sum of the voltages
across each resistor, Veq=V1+V2+V3 while in parallel connection,
when the resistors are connected in parallel, the total voltage, V
are same across it, Veq=V1+V2+V3.The instrument for measuring
potential difference is voltmeter.
INTRODUCTIONEXPERIMENT 6B: RESISTANCES IN CIRCUITS
Resistors are used to control the amount of current. Resistors
have resistances ranging from less than an ohm to millions of ohms.
When two or more resistors are connected in series, the same
current, I passes through each resistor. Another way to connect
resistors is parallel which is has the same voltage across it.
EXPERIMENT 6C: VOLTAGES IN CIRCUITS
Voltage is the potential difference between its ends. It
measures the potential energy of an electric field to cause an
electric current in electrical conductor. Instrument for measuring
potential difference is voltmeter.
OBJECTIVE
EXPERIMENT 6B: RESISTANCES IN CIRCUITS
This experiment is to begin experimenting with the variables
that contribute to the operation of an electrical
circuit.EXPERIMENT 6C: VOLTAGES IN CIRCUITS
The objective of this experiment is experimenting with the
variables that contribute to the operation of an electrical
circuit.
THEORY
EXPERIMENT 6B: RESISTANCES IN CIRCUITS
In series connection, the total resistance is the sum of the
resistors, Req=R1+R2+R3 while in parallel connection, the total
resistance are, Req=1/R1+1/R2+1/R3.EXPERIMENT 6C: VOLTAGES IN
CIRCUITS
In series connection, the equivalent voltage is Veq=V1+V2+V3
while in parallel connection the equivalent voltage are same across
each resistor, Veq=V1=V2=V3.
PROCEDURE
EXPERIMENT 6B: RESISTANCES IN CIRCUITS1- We choose the three
resistors having the same value .we enter those sets of color in
the table 4.1.we refer to one as # 1, another as #2 ,and the third
as #3.
2-After determined the coded value of the resistor ,we enter in
the table 4.1 as the coded Resistance the tolerance value as as
indicated by the color of the fourth band under the Tolerance.
3-we use the multimeter to measure the resistance of each of the
three resistances that,and entered the values in the table 4.1.
4-The error of each resistances and the values in table 4.1.
Experimental Error = ((measured-coded)/coded)x 100%
5-Firstly , we connected the three resistors into the SERIES
CIRCUIT ,figure 4.1.we used the spring clips on the circuits
Experiments Boards to hold to lead of the resistors together
without bending them.
6-After that,construct a PARALLEL CIRCUIT, first using
combination of the two resistors , and then using all the three,we
are measured and record our values for these circuits.
7-Connect the COMBINATION CIRCUIT in the figure and measure the
various combinations of the resistance.
8-After finish with the same resistor ,we change with 3
resistors having different values,and repeat the steps 1-7 as
above, we recorded our data in the table.and we had called these
resistors with A,B,C.
EXPERIMENT 6C: VOLTAGES IN CIRCUITS1. Three equal resistors is
connected into the series circuit like the shown below, by using
the springs to hold the leads of the resistors together without
bending them. Two wires are connected to the D-cell, carefully
noting which wire is connected to the negative and which is
connected to the positive.
2. Then, the voltage function on the Multimeter was used to
measure the voltages across the individual resistors and across the
combinations of resistors. The polarity of the leads (red was +,
black was -) was carefully observed. The readings were
recorded.
3. Then, the parallel circuit was connected by using all the
three resistors. The voltage was measured across each of the
resistors and the combinations.
4. Next, the circuit below was connected and the voltages were
measured. The previous resistance readings could be used for this
step.
APPARATUS
EXPERIMENT 6B: RESISTANCES IN CIRCUITS
EQUIPMENT NEEDED:
Circuit Experiment Boar
Multimeter
Resistors
EXPERIMENT 6C: VOLTAGES IN CIRCUITS
EQUIPMENT NEEDED:
Circuit Experiment Board
D-cell Battery
Wire Leads
Multi meter
Resistors
RESULTS
Table 4.1
Colorscodec resistance/measured resistance/error%tolerance%
1st2nd3rd4th
#1Green Blue BrownGold5605550.890.1
#2Green Blue BrownGold5605531.250.1
#3Green Blue BrownGold5605521.430.1
Series
R12= 1.108k R23= 1.109k R123=1.663kParallelR12=0.554k
R23=0.282k
R123=0.553k CombinationR1=0.554k R23=0.2786 kR123=0.834k Table
4.2
Colorscodec resistancemeasured resistance/%errorTolerance
1st2nd3rd4th
#Aredredyellowgold2200002170002.360.1
#Bredredyellowgold2200002172001.270.1
#Credredyellowgold2200002173001.230.1
Series (figure 4.4)
RAB=0.432m
RBC=0.432m
RABC=0.649m
Parallel (figure 4.5)
RAB=216.6k RBC= 108.1k RABC=72.1k Combination (figure 4.6)
RAB=215.8k RBC=108.6k RABC=324.4kRESULTS 6(C) Series (figure
5.1)
R1= 215.7k
V1=1.2Mv R2=216.6k
V2=4.5mV R3=216.6k
V3=4.4mV R12=1.108k
V12=4.5mV R23=1.109k
V23=5.6mV R123=1.663k
V123=5.3mV Parallel(figure 5.2)
R1=0.1175k
V1=4.9mV
R2=0.118k
V2=4.8mV
R3=0.116k
V3=5.1mV
R123=0.117k V123=4.8mV
Combination (figure 5.3)
R1=0.554k
V1=4.8mV
R23=0.2786k V23=4.6mV
R123=0.834k V123=5.0mV
Series(figure 5.4)
RA=217.5k
VA=4.9mV
RB=217.4k
VB=1.0mV
RC=217.7k
VC=1.0mV
RAB=0.432m VAB=1.1mV
RBC=0.432m VBC=3.2mV
RABC=0.649m VABC=4.7mV Parallel (figure 5.5)
RA=0.757k
VA=1.2mV
RB=0.758k
VB=1.3mV
RC=0.756 k
VC=4.7mV
RABC=0.759k VABC=1.2mV
Combination (figure 5.6)
RA=215.k
VA=1.9mV
RBC=108.6k VBC=4.6mV
RABC=324.4k VABC=4.0mVCALCULATIONSTable 4.1
Percentage error (%) #1=(555-560 )x100
560
= 0.89%
Percentage error (%) #2=(553-560 )x100
560
= 1.25%
Percentage error (%) #3=(552-560 )x100
560
= 1.43%
Table 4.2
Percentage error (%) #1=(217k- 220k)x100
220k
= 1.36%
Percentage error (%) #2=(217.2k-220k)x100
220k
= 1.27%
Percentage error (%) #3=(217.3k-220k)x100
220k
= 1.23%
DISCUSSIONS
EXPERIMENT 6B: RESISTANCES IN CIRCUITS1. How does the % error
compare to the coded tolerance for your resistor?
The % error for the same value of the resistor is 99.99, however
the coded tolerance is 0.1r the three sets of colours. There are
#1, #2 and #3. Besides that , the % error for the different values
is 99.98% until 99.99% and tolerance is 0.1r the four colours.
2. What is the apparent rule for the total resistance when
resistor are added up in series ? In parallel ?
The total resistance when resistor are added up in series
circuits is will become increase, but the current through the
circuit will decrease .Besides that , we used to get the total
resistance by the equation Req = R1 + R2 + R3. However , the total
resistances in parallel circuit will become decrease , but the
current through the circuit will increase. Although we also used to
get the total resistance by equation in parallel circuit ,
1/Req = 1/R1 + 1/R2 + 1/R3
3. What is the apparent rule for combining equal resistances in
series circuit ? In parallel circuits ?
In combination equal resistance in series circuits the
resistances get distributed equally through each resistor . However
the equal resistance in parallel , resistance is to through
cicuit.
4. What is the apparent rule for combining unequal resistances
in series circuit ? In parallel circuit ?
In combination unequal resistance in series circuit , the
resistance values are distributed based on the resistance value
given by the formula Ohms law V = IR. However , the unequal
resistances in parallel circuits, resistance are at the same
potential.
EXPERIMENT 6C: VOLTAGES IN CIRCUITS
1. Based on the data from Figure 5.5 , what is the pattern for
how voltage distributed itself in a parallel circuit for unequal
resistances ? Is there any relationship between thesizeof the
resistance and the size of the resulting voltage ?
Since the current is different on each component of the parallel
circuit , change in the size of the resistance does no effect size
of the resulting voltage . In figure the voltage across the each
resistor are the same.
2. On the basis of the data you recorded on the table with
Figure 5.4 , what is the pattern for how voltage gets distributed
in a series circuit with equal resistance?
The voltages have different value across each of the resistor in
a series circuit since the resistance is indirectly proportional to
the voltage . However , the current (1) is always constant along
this type of circuit.
3. According to the data you recorded with Figure , what is the
pattern for how voltage gets distributed in a series circuit with
unequal resistance ? Is there any relationship between the size of
the resistance and the size of the resulting voltage?
Similar to the Figure , the voltage have different values across
each of the resistor, even though the resistance have different
value each. The change in value of the resistor does not affect the
value of voltage distributed in the series circuit.
4. Utilizing the data from Figure , what is the pattern for how
voltage distributes itself in parallel circuit for equal
resitance?
In this type of circuit , the voltage across the resistor are
the same . The resistors have the same value but the current is
changed across the circuit
CONCLUSIONS
The experiment has done does illustrate the theory of Ohms Law.
The relationship between the three variables has apparently
demonstrated in this experiment . In experiment 6B the concept of
the total resistance is prove by the calculating the resistance in
the series , parallel and combination of both circuit. The variable
in this experiment is the resistance values that have used. Not
just that, the percentage error of the resistor can be calculated
by the equation
Percentage error % = (measured value coded value) x 100%
Furthermore, this method also determine the current of the
circuit , either its in series or parallel . Experiment 6C
established the idea of the relationship between the voltage and
the resistance by measuring the voltage across each of the resistor
, with same and different values of the resistance. Moreover, even
though the experiment was quit hard, students able to finish it on
time and gain more experience in the lab.
RECOMMENDATIONS
1. Student sometime confused about wire that they have
connected,whether it is in connecting to the right position.This
action can lead miscalculation in reading the resistance.
2. Student must careful when connecting the wires.
3. Student should always compare their circuits with the diagram
given in the lab manual.
4. Determining the colour coded resistor and its values
properly.
REFERENCES
PHYSIC GIANCOLI (SIXTH EDITION)
DOUGLAS C. GIANCOLI
MANUAL LAB ENGENEERING PYHSICS LABAROTORY (CHE 175)
PROGRAM MATRIKULASI MODUL FIZIK
EDISI PERTAMA 1999
PROF. MADYA DR. ELIAS SAION
PROF MADYA DR. AZIZAN ISMAIL
APPENDICE
NAME : ABDUL HALIM BIN NORDIN (2008293172)
MUHAMMAD RAZI BIN ZAHARI (2008424824)
NOOR SYAFIQAH AMERAH BT AHMAD TARMIZI (2008293072)
SITI NOR SAMRAH BT A.RAHIM (2008291992) NURUL ADILAH BT
NASARUDDIN (2008292022)
GROUP : 2
EXPERIMENT : (6) 1-RESISTANCES IN CIRCUITS
2-VOLTAGES IN CIRCUITS
3-CURRENTS IN CIRCUITS
DATE PERFORMED : 25 FEBRUARY 2009
SEMESTER : DIS 2008 APRIL 2009
PROGRAMME/CODE : DIPLOMA IN CHEMICAL ENGINEERING / EH 110