Prepared by Mr. Güner Buğrahan & Dr Erkut inan İşeri
PHY 102 LAB
EXPERIMENT V
The Kirchhoff’s rules
Theory
There are two rules devised by G. R. Kirchhoff (1824-1887). Kirchhoff’s first or junction
rule is based on the conservation of charge and states that at any junction point, the sum of all
currents entering the junction must equal the sum of all currents leaving the junction.
Kirchhoff’s second or loop rule is based on the conservation of energy and states that the sum
of the changes in potential around any closed path of a circuit must be zero.
In this experiment by using circuit experiment board and resistors shown in Figure V.1, you
will experimentally demonstrate Kirchhoff’s Rules for electrical circuits.
Kirchhoff’s rules
1) Junction rule: At any junction point, the sum of all currents entering the junction must
equal the sum of all currents leaving the junction.
2) Loop rule: The sum of the changes in potential around any closed path of a circuit must be
zero.
Figure V.1. a)Circuit experiment board.
b) DC power supply
Procedure:
1. Construct the circuit shown in Figure V.2 by using circuit experiment board and DC power
supply shown in Figure V.1.
2. Determine the resistance of resistors from color codes by using method defined in
Appendix A.
3. By connecting ammeter to a suitable place in the circuit, measure currents I1, I2, and I3 one
by one.
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Prepared by Mr. Güner Buğrahan & Dr Erkut inan İşeri
4. Remove the batteries and measure the equivalent resistance by connecting ohm meter to the
terminals of circuit.
EXPERIMENT V
Student Name:
Date :
Student No
Lab. Group No :
:
Name of the Experiment:
Purpose:
Apparatus:
OBSERVATIONS & MEASUREMENTS
Measure: I1=
I2=
I3=
Req=
R2
R1
R3
R4
Figure V.2.
1) Calculate theoretically by using Kirchhoff’s rules I1 ,I2, I3 and compare with experimental
results.
Coded Resistors R1=
R2=
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R3=
R4=
PHY102 EXP V Page 2
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2) Calculate the equivalent resistance Req of the circuit.
3) Conclusion
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