Resistances, Voltages and Current in Circuits - Copy

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


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


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


EQUIPMENT NEEDED:

Circuit Experiment Boar

Multimeter

Resistors


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



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%


560

= 1.25%


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.


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

Resistances, Voltages and Current in Circuits - Copy

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