PHY112
Experiment No: 01
Name of Experiment: Verification of Kirchhoff's Voltage Law (KVL) and Kirchhoff's
Current Law (KCL)
Theory I:
Kirchhoff’s Voltage Law (KVL) states that in a loop, the sum of the voltage
drops across all the resistors is equal to the voltage supplied by the source.
Now, consider the circuit below:
Figure 1: Loop circuit
Applying KVL, we can write:
V =V1+V2+V3
or,
1
V = i(R1 + R2 + R3)
Apparatus:
DC Voltage source, resistors, ammeter, voltmeter, wires.
Procedure I:
(1) Measure the three resistors and connect the circuit as shown in the figure.
(2) Set V = 5 V.
(3) Measure the current i in the circuit.
Results Calculations I:
Verification of KVL:
Source voltage, V = .......... V.
Current in the circuit, i = ............. A.
Voltage drop across R1, V1 = iR1 = .............. V.
Voltage drop across R2, V2 = iR2 = .............. V.
Voltage drop across R3, V3 = iR3 = .............. V.
Total voltage drops = V1 + V2 + V3 = ............... V.
Comment:
2
Theory II:
Kirchhoff’s Current Law (KCL) states that in a node, the total incoming
current equals the total outgoing current. Now, consider the circuit below:
Figure 2: Node circuit
Applying KCL, we can write:
I = i1 + i2 + i3
or,
I =V(
1
1
1
+
+
)
R1 R2 R3
Procedure II:
3
(1) Measure the three resistors and connect the circuit as shown in the figure.
(2) Set V = 5V .
(3) Measure the incoming current, I A.
Results Calculations II:
Verification of KCL:
Source voltage, V = .......... V.
Incoming current, I = ............... A.
Current through R1, i1 =
V
R1
= .............. A.
Current through R2, i2 =
V
R2
= .............. A.
Current through R1, i3 =
V
R3
= .............. A.
Total outgoing current = i1 + i2 + i3 = ............... A.
Comment:
4