Python Notes for mca i year students osmania university.docx
Kirchoff law
1. PRACTICUM REPORT
BASIC PHYSICS II
"KIRCHOFF LAW"
COLLECTION DATE: 16th
of March 2018 M
DATE: 11th
of March 2018 M
NAME : Utut Muhammad
"KIRCHOFF’S LAW"
FINAL PROJECT PRACTICUM
A. OBJECTIVE
1. Studying Kirchoff's Law
2. Analyzing the series using Kirchoff Law
3. Compares the current value specified by an Ammeter with the results of
a series analysis calculation.
4. Identify what happens when the voltage value is raised.
B. BASIC THEORY The
a number of voltage values in a closed circuit is always zero. The value will
always be zero because there is a voltage that has a negative value. Negative
voltages are usually found in voltage sources such as batteries or power
supplies. This is often used in simple settings. This statement is called
Kirchhoff's Law. (Blocer, 2003: 6-7)
A direct current (DC) is an electric current flowing in the wire of a
string because of the potential difference by 2 poles whose polarity is
constant. The opposite is alternating current (AC) caused by the current
source with the polarity of the two functions of the time.
The source of electric current and back and forth is called the force
of electricity or electric power and is also called emf (electromotive force).
There is an oddity in the mention of emf because it means an electric motion
force, but it is united with joules. To explain the relationship between
2. KIRCHOFF LAW UTUT MUHAMMAD
electric current, emf, and resistance in a closed circuit in the same direction
can be used Kirchoff's Law. (Jati, 2009: 361)
On the basis of a simple circuit can be analyzed by using equations
and with series or parallel in each resistor by simplifying the circuit into a
loop circuit. So the purpose of Kirchoff's rule is to analyze more complex
circuits in order to simplify the simplification well so that the two principles
of Kirchoff's Law are used. Kirchoff's law is a law to make it easier for us
to calculate flows in a circuit that is quite complicated and cannot be solved
directly. In other cases, actually, Kirchoff's Law is the application of the
Law of Energy Conservation. (Giancoli, 2014: 105)
For each closed path in a series, Kirchhoff's Voltage Law states that
the number of other algebraic voltages is produced by currents in passive
elements which produce voltage, which is sometimes referred to as voltage
drop. This law also applies to circuits that are driven by sources. (Nahvi,
2004: 17) The
inventor of Kirchoff's Law was a German physicist named Gustav
Kirchoff. He succeeded in developing spectroscopy and science tools
related to emission spectroscopes. Kirchoff also managed to conclude that
a line spectrum would be obtained if the light was passed into a gas. Using
a spectroscope, Kirchoff also managed to show that each element if heated
would produce a certain emission line pattern. These results can be used to
identify cesium elements in 1860 and rubidium in 1861. (Umar, 2008: 126)
Ohm's Law and Kirchoff's Law do dominate the theory of circuit
analysis. But the three Laws will not be enough when people have to analyze
the changes in each parameter in the series. So that in an electrical circuit in
the form of two serial loops it contains parameters which consist of a
constant source of pressure and a number of resistors that know the value of
the resistance and the voltage source that changes. (Sutrisno, 1986)
According to Giancoli Douglass, Kirchoff's Law is divided into two
parts, namely Kirchoff's I Law and Kirchoff's II Law. Law I Kirchoff or the
so-called law of the branch point is based on the conservation of electric
3. KIRCHOFF LAW UTUT MUHAMMAD
charge, which reads: "At any point in the branch, the sum of all currents
entering a branch, should be equal to all currents leaving the current."
𝐼𝑚𝑎𝑠𝑢𝑘Σ=Σ
𝐼𝑘𝑒𝑙𝑢𝑎𝑟'slaw Kirchoff also called The Law of Knots or Intersections
which are understood as the sum of all currents leading to a node (i.e. the
intersection where three or more sources or branches of current are
connected) must be equal to the sum of all currents leaving the node. If we
determine the inflow as positive and the outflow as negative, then the
number of flows equals zero is a common alternative to the rule. The current
always flows from a high potential to a high potential to a low potential
through a resistor. When passing through a resistor in the current direction,
the potential change is negative because of a potential decrease. The positive
terminal of a pure source of electromotive force (emf) is always a terminal
with a high totential and does not depend on the direction of the current
passing through the source of the electromotive force (emf). (Bueche, 2006:
202)
"at each branch point, the sum of all flows entering the branch must
be the same as all the currents leaving the branch" (Giancoli, 2014: 105).
(Figure 1. Example of the number of currents entering the branch.
Http://www.rumusmatematika.me/2016/11/pengertian-dan-hukum
Kirchoff-ii.html)
Sounds of Kirchoff II's Law namely voltage (difference potential) in
a closed circuit is zero, for example, we buy goods and pay according to the
4. KIRCHOFF LAW UTUT MUHAMMAD
price (comparable). This is like Kirchoff's Law I. Kirchoff II's Law states
that:
(Figure 2. Amount of potential around lines in a circuit must be 0.)
Kirchhoff's second law becomes formulated: becomes
ΣΔ𝑉= 0
(Giancoli, 2014)
Kirchhoff's I Law is charge conservation law which states that the
amount of charge flowing does not change. This means that the charge rate
(current strength) leading to the branch point is equal to the rate of charge
(current strength) leaving the branch point. (Surya, 2009: 95)
Kirchhoff's law for voltage states that the amount of voltage in a
closed circuit is zero. Polarity or direction of voltage depends on the
direction of electric current. The current will flow from a potential or higher
voltage point to a potentially lower point. The point that has a lower voltage
is a point that has positive polarity, and a point that has a lower voltage is a
point with negative polarity. (Zuhal, 2004: 16-17)
C. TOOLS AND MATERIALS
N
O
PICTURES
NAME OF
TOOLS AND
MATERIALS
AMOUNT
5. KIRCHOFF LAW UTUT MUHAMMAD
1 Power Supply
2 Fruit
2 Barriers
1 Fruit
3 Multimeter
3 Fruit
4
Connecting
Cables to
Sufficient
5 Resistor
3 Fruit
6 Jumper to
taste
7 Crocodile Capit
Enough
D. WORK STEPS
Experiment I
Change the voltage at E1
NO IMAGES WORK STEP
6. KIRCHOFF LAW UTUT MUHAMMAD
1 Prepare tools and materials
2
Make a Kirchoff series with the
sketch guide that was shown
in Figure
3
Turn on multimeter by turning
the selector on a DC current
with 10A
4
Turn on the first power supply
or V1 and rotate the selector
according to the data provided
5
Record the results of the
practicum data obtained.
Experiment II
Replace the voltage at E2
NO IMAGE WORK STEP
1 Prepare tools and materials
7. KIRCHOFF LAW UTUT MUHAMMAD
2
Make a Kirchoff series with the
sketch guide that was shown
in Figure
3
Turn on multimeter by turning
the selector on a DC current
with 10A
4
Turn on the second power
supply or V2 and rotate the
selector according to the data
provided
E. DATA EXPERIMENT
Experiment I
Replace the voltage at V1
No 𝜀1(V) 𝜀2(V) I1 (A) I2 (A) I3 (A)
1 2 V 3 V 0 0.18 0.18
2 4 V 3 V 0.03 0.24 0.27
3 6 V 3 V 0.07 0.3 0.36
Experiment II
Replace the voltage at V2
No 𝜀1V 𝜀2V I1 (A ) I2 (A) I3 (A)
1 2 V 3 V 0 0.18 0.18
2 2 V 6 V -0.03 0.31 0.25
3 2 V 9 V -0.07 0.43 0, 34
F. DISCUSSION
In this practice, we have conducted several experiments to prove
Kirchoff's Law, where the practitioner uses two power supplies as a voltage
source and three resistors with resistance on the first resistor 22 Ω, the
second 12 Ω, and the third 15 Ω. Praktikan conducted two experiments
8. KIRCHOFF LAW UTUT MUHAMMAD
where experiments with normal polarity but the values on V1 and V2 were
changed, but at the time of the lab began, it was found that the amperemeter
used to maintain the I3 current was unstable, and turned on he showed the
number -0, 01 Ampere.
In the first practicum, with a value of 𝜀1 which is changed, that is,
with a value of 2 volts, 4 volts, and 6 volts, while the value of 𝜀2 is fixed.
Based on the experimental data that has been obtained by the practitioner, it
is clear that thevalue of kepadachange in1 has an effect on the flowing
electric current, where when the voltage 𝜀1 is greater, the value of the
current in each amperemeter will be even greater. In this first Kirchoff Law
practice the value of 𝐼3 smaa with a value of 𝐼1, which when added to the
value of 𝐼2, at a voltage of 4 volts also has thevalue of same𝐼3 when 𝐼1 is
added to the value 𝐼2 except for the voltage source using the value of 6 volts,
then the current that is owned is different from the voltage values V1, and
V2.
In the next practicum, there is a fixed (unchanging) source value at
𝜀1, which is fixed, while thevalues yaitu2change, namely 3 volts, 6 volts,
and 9 volts. From the experimental data that have been obtained by the
practitioner, it was obvious that the value of ε2 fickle also gives effect to the
current flow, wherein if the value ofthe ε2 the greatervoltage,t he current
value at each ammeters would be even greater. In this second practicum ,the
value of 𝐼3 is not the same as the value of 𝐼1, which is summed with 𝐼2, as
well as the second experiment with the power source at 𝜀1 which is different
when added 𝐼1 and 𝐼2, which results do not match 𝐼3. This seems occurs
because of a practice error in viewing the ammeters, because based on the
calculation of the circuit analysis the value of 𝐼1 should be positive at the 9
volt and 6 volt voltage sources.
Based on the second data from the trial results, if the voltage value
gets bigger, then the value of the current will be even greater, and vice versa,
if the voltage value gets smaller, then the value of the current flowing will
9. KIRCHOFF LAW UTUT MUHAMMAD
be even smaller. This is in accordance with the relation to Ohm's Law, that
the voltage value will be directly proportional to the current flowing.
The results of the circuit analysis written in the post-practicum
assignment have values from the results of calculations with readable values
on the ammeters that are close to but there are also appropriate or
appropriate values for the first and second practicums, while in this lab we
get the same three data if 𝐼1 and 𝐼2 were added to these two experiments,
and the calculated values with the values read on the ammeters must have
varied, namely at 𝐼1 where the calculated values have positive and negative
values in calculating the data and data obtained when practicum.
Before doing a practicum, practice beforehand it has been
hypothesized in advance that the current value measured in ammeters based
on practicum values is greater than the results. The hypothesis is very simple
but it is done to answer the pretest only. In the calculation of circuit analysis,
this can happen because the calculation of circuit analysis only calculates
the resistance value that exists in the resistor, when in fact there are also
wire barriers and resistance to the power supply, and this is evident in the
results of calculation of circuit analysis.
When our labs get new things in our day without accident, suddenly
one of the resistors is burned so that the resistor becomes burnt on the color
bracelet, this is because the tension source is too high, causing the resistor
to burn, and also the negligence of the practitioner. those who do not
understand Kirchoff's practicum, in this Kirchoff Law practicum the
practitioner can practice this Kirchoff Law until it is finished with Reza's
guidance.
G. POST PRACTICUM TASKS
1. Explain the shortcomings of series, parallel, and parallel series! Include
the solution!
Answer:
a. The series circuit has the same large current on each obstacle (eg
lights) because the amount of charge that passes through obstacle 1
10. KIRCHOFF LAW UTUT MUHAMMAD
will also pass the obstacle 2 at the same time interval. Two elements
are in a series if only have a main point that is not connected to the
current carrying element on a network.
b. In series, material series does not need a cost that is quite expensive
because it requires a little cable, but when there is an electrical surge
all the obstacles (lights) will completely extinguish because all
current lines will be cut off. The popularity of series lights is reduced
due to the search for broken lights must try to replace a good light
bulb on each seat along with the series until a broken light bulb is
found. Series lights are safer to use in Christmas tree decorations.
Where the series operates with less energy in each lamp and has a
lower temperature.
c. Parallel circuits, each obstacle (such as a light bulb) has the same
resistance. Where based on the design of parallel pairs of light bulbs
that are brighter than mounted series, your name is also hotter than
series. (Serway, 2010)
2. Calculate the magnitude of 𝐼1,𝐼2, and 𝐼3 that flow by analyzing the
circuit that you practice using Kirchhoff's law! Are there differences in
the values of 𝐼1,𝐼2, and 𝐼3 based on the results of your calculations with
the values 𝐼1,𝐼2, and 𝐼3 that are read by the ammeters? Explain!
Answer:
Kirchhoff's I Law: 𝐼3 =𝐼1+𝐼2 …………… (1)
Loop 1: 𝜀2−𝐼3𝑅2−𝐼1𝑅1 = 0 𝜀2 =𝐼3𝑅2+𝐼1𝑅1 …………… (2)
Loop 2: 𝜀1−𝐼2𝑅3+𝐼1𝑅1 = 0 𝜀1 =𝐼2𝑅3−𝐼1𝑅1 …………… (3)
Equation substitution (1 ) to (2):
𝐼3 =𝐼1+𝐼2
𝜀2 = (𝐼1+𝐼2)𝑅2+𝐼1𝑅1
𝜀2 =𝐼1𝑅2+𝐼2𝑅2+𝐼1𝑅1 …… ……… (4)
Elimination of equations (4) and (3):
𝜀2 =𝐼1𝑅2+𝐼2𝑅2+𝐼1𝑅1
11. KIRCHOFF LAW UTUT MUHAMMAD
𝜀1 =𝐼2𝑅3−𝐼1𝑅1 ..... +
𝜀1+𝜀2 =𝐼1𝑅2+𝐼2𝑅2+𝐼2𝑅3 …………… (5)
Change equation (5) to 𝐼1: 𝜀1+𝜀2 =𝐼1𝑅2+𝐼2𝑅2+𝐼2𝑅3 𝐼1
=𝜀1+𝜀2−𝐼2𝑅2−𝐼2𝑅3𝑅2 …………… (6)
Change equation (5) to 𝐼2: 𝜀1+𝜀2−𝐼1𝑅2 =𝐼2𝑅2+𝐼2𝑅3 𝜀1+𝜀2−𝐼1𝑅2
=𝐼2 (𝑅2+𝑅3) 𝜀1 +𝜀2−𝐼1𝑅2𝑅2+𝑅3 =𝐼2
𝐼2 =𝜀1+𝜀2−𝐼1𝑅2𝑅2+𝑅3 …………… (7)
Substitution of equations (7) to (3 ) and get the value 𝐼1: 𝜀1
=𝐼2𝑅3−𝐼1𝑅1
𝜀1 = (𝜀1+𝜀2−𝐼1𝑅2𝑅2+𝑅3)𝑅3−𝐼1𝑅1
𝜀1 =𝜀1𝑅3+𝜀2𝑅3−𝐼1𝑅2𝑅3𝑅2+𝑅3−𝐼1𝑅1 𝜀1
=𝜀1𝑅3+𝜀2𝑅3−𝐼1𝑅2𝑅3−𝐼1𝑅1𝑅2−𝐼1𝑅1𝑅3𝑅2+𝑅3 𝜀1𝑅2+𝜀1𝑅3
=𝜀1𝑅3+𝜀2𝑅3−𝐼1𝑅2𝑅3−𝐼1𝑅1𝑅2−𝐼1𝑅1𝑅3 𝐼1𝑅1𝑅2+𝐼1𝑅2𝑅3+𝐼1𝑅1𝑅3
=𝜀1𝑅3+𝜀2𝑅3−𝜀1𝑅2−𝜀1𝑅3 𝐼1 (𝑅1𝑅2) +𝑅2𝑅3+𝑅1𝑅3)
=𝜀1𝑅3+𝜀2𝑅3−𝜀1𝑅2−𝜀1𝑅3 𝐼1 =𝜀2𝑅3−𝜀1𝑅2𝑅1𝑅2+𝑅2𝑅3+𝑅1𝑅3
…………… (8)
Subs substitute equation (6) to (3) and get the value 𝐼2: 𝜀1
=𝐼2𝑅3−𝐼1𝑅1
𝜀1 =𝐼2𝑅3− (𝜀1+𝜀2−𝐼2𝑅2−𝐼2𝑅3𝑅2)𝑅1 𝜀1 =𝐼2𝑅3−
(𝜀1𝑅1+𝜀2𝑅1−𝐼2𝑅1𝑅2−𝐼2𝑅1𝑅3𝑅2) 𝜀1 =𝐼2𝑅2𝑅3 -
𝜀1𝑅1−𝜀2𝑅1+𝐼2𝑅1𝑅2+𝐼2𝑅1𝑅3𝑅2 𝜀1𝑅2
=𝐼2𝑅2𝑅3−𝜀1𝑅1−𝜀2𝑅1+𝐼2𝑅1𝑅2+𝐼2𝑅1𝑅3 𝐼2𝑅2𝑅3+𝐼2𝑅1𝑅2+𝐼2𝑅1𝑅3
=𝜀1𝑅2+𝜀1𝑅1+𝜀2𝑅1 𝐼2 (𝑅2𝑅3+𝑅1𝑅2+𝑅1𝑅3) =𝜀1𝑅2+𝜀1𝑅1+𝜀2𝑅1 𝐼2
=𝜀1𝑅2+𝜀1𝑅1+𝜀2𝑅1𝑅1𝑅2 +𝑅1𝑅3+𝑅2𝑅3 …………… (9)
Substitution of equations (8) and (9) to (1)
𝐼3 =𝐼1+𝐼2
𝐼3 = (𝜀2𝑅3−𝜀1𝑅2 /𝑅1𝑅2+𝑅2𝑅3+𝑅1𝑅3) + (𝜀1𝑅2+𝜀1𝑅1𝜀2𝑅1
/𝑅1𝑅2+𝑅1𝑅3+𝑅2𝑅3)
16. KIRCHOFF LAW UTUT MUHAMMAD
𝐼3 =
𝜀2𝑅3 + 𝜀1𝑅1 + 𝜀2𝑅1
𝑅1𝑅2 + 𝑅2𝑅3 + 𝑅1𝑅3
𝐼3 =
(6)(15) + (2)(22) + (6) (22)
264 + 180 + 330
𝐼3 =
90 + 44 + 132
264 + 180 + 330
𝐼3 =
266
774
𝐼3 = 0.343669𝐴
At I3
𝐼3 =
𝜀2𝑅3 + 𝜀1𝑅1 + 𝜀2𝑅1
𝑅1𝑅2 + 𝑅2𝑅3 + 𝑅1𝑅3
𝐼3 =
(9)(15) + (2)(22) + (9) (22)
264 + 180 + 330
𝐼3 =
135 + 44 + 198
264 + 180 + 330
𝐼3 =
377
774
𝐼3 = 0.343669𝐴
3. Make a conclusion that you get from the results of the lab and compare
the truth with t existing eori!
Answer:
✔ Values in Kirchoff's Law calculations are more accurate than the
values indicated on the ammeters because the current flowing in
imperfectly enters the circuit.
✔ The amount of all flows entering the branching will be the same
as the amount of current coming out of the branching.
✔ The greater the voltage flowed in the circuit, the greater the
current.
✔ A current that is negative in reverse polarity indicates that the
sequence that has been compiled is wrong and reversed.
✔ Kirchoff's Law is a rule law analyzing a series of loops with the
principle of derivative law of Conservation of Energy and
Energy.
H. CONCLUSION
Based on the practicum that has been done, it can be concluded that:
17. KIRCHOFF LAW UTUT MUHAMMAD
1. Kirchhof Law has two. Kirchhoff's first law says that the current
entering at each branch point, the value will be the same as all the
currents leaving the branch. While Kirchhoff's second law states that
the voltage change in a closed circuit (loop) is zero.
2. If the voltage value is greater, then the value of the current will also be
greater, and vice versa, according to Ohm's Law that the value of the
voltage will be directly proportional to the current flowing.
3. Values in Kirchoff's Law calculations are more accurate than the values
indicated on the ammeters, because the current flowing in imperfectly
enters the circuit.
4. The greater the voltage flowed in the circuit, the greater the current
that exists
I. COMMENTS
1. Mastering the material of the Kirchoff Law practicum well to facilitate
us in practicum.
2. Understand and understand the concepts of Kirchoff Law so that there
is no mistake in practicum.
3. Understand each step taken while conducting an experiment.
4. Take care in the experiment, because carelessness during practicing
can cause damage to the equipment.
J. REFERENCES
Blocker, Richard. 2003. Basic Electronics. Yogyakarta: Andi Yogyakarta.
Bueche, Frederick and Eugene Hecht. 2006. Ten Physics University Edition.
Jakarta: Erlangga
Giancoli, Douglas C. 2014. Physics: Principles and Applications of the
Seventh Edition
Volume 1. Jakarta: Erlangga.
Jati, Bambang Murdaka Eka. 2009. Basic Physics for Students of Computer
Science and Informatics. Jogjakarta: ANDI
Nahvi, Muhammad. 2004. Electrical Circuits. Jakarta: Erlangga
Surya, Yohanes. 2009. Electricity and Magnet. Tangerang: PT Kandell.
18. KIRCHOFF LAW UTUT MUHAMMAD
Sutrisno. 1986. "Basic Electronic Theory and Its Application". Bandung.
ITB.
Umar, Efrizon. 2008. Smart Books on Physics. Jakarta: PusindoMedia
Zuhal. 2004. Basic Principles of Electronics. Jakarta: Main Gramedia
Library.
HTTP: //www.rumusmatematika.me/ 2016/11 / understanding-and-law
Kirchoff-ii.html
K. APPENDIX
