Kirchhoff's laws describe the relationship between voltage and current in electrical circuits. Kirchhoff's voltage law states that the total voltage supplied by the source must equal the total voltage used by all loads in a series circuit. Kirchhoff's current law states that in a series circuit, the total current is the same at any point, while in a parallel circuit the total current splits among the branches. The document provides examples applying Kirchhoff's laws to calculate voltages and currents in different circuit configurations.

1. Kirchhoff’s Law

2. Kirchhoff’s Law
Kirchhoff’s Voltage Law: In a series circuit, the total
voltage supplied by the source must equal the total
voltage used by all of the loads in that path.
5V 2V 3V
Total = 10 V
10 V

3. Kirchhoff’s Law
Kirchhoff’s Voltage Law: In a series circuit, the total
voltage supplied by the source must equal the total
voltage used by all of the loads in that path.
Analogy:
Total potential energy gained
Total potential energy lost

4. Kirchhoff’s Law
Kirchhoff’s Voltage Law: In a parallel circuit, the total
voltage supplied by the source is equal to the voltage
across each parallel branch* 5V
5V
5V
*as long as all 5V
loads are identical

5. Kirchhoff’s Law
Kirchhoff’s Voltage Law: In a parallel circuit, the total
voltage supplied by the source is equal to the voltage
across each parallel branch.
Analogy:
Total potential energy lost
Total potential energy gained

6. Calculate the Potential Differences
L2
Vs 10 V
L1 V1 10 V
S 10 V V2 10 V

7. Calculate the Potential Differences
1V
L1 L2
Vs 2 V
S V1 1 V
2V
V2 1 V

8. Calculate the Potential Differences
1V
L3
Vs 1V
L2
V1 1V
L1 V2 1V
S V3 1V
1V

9. Calculate the Potential Differences
L1 L2 L3
Vs 8V
2V 3V V1 3V
S
8V V2 2V
V3 3V

10. Kirchhoff’s Law
Kirchhoff’s Current Law: In a series circuit, the total
current flowing through the circuit is identical at any point
in the circuit.
2A 2A 2A
2A

11. Kirchhoff’s Law
Kirchhoff’s Current Law: In a series circuit, the total
current flowing through the circuit is identical at any point
in the circuit.
Analogy:
Point A Point B
Same current

12. Kirchhoff’s Law
Kirchhoff’s Current Law: In a parallel circuit, the total
current flowing through the circuit is divided up among
any parallel branches.
6A
2A 1A 3A

13. Kirchhoff’s Law
Kirchhoff’s Current Law: In a parallel circuit, the total
current flowing through the circuit is divided up among
any parallel branches. Point B
Analogy:
Point A
Point C
Point D
Current at point A = current at point B + point C + point D

14. Calculate the Currents
L2
Is 15 A
L1 9 A I1 9 A
S 15 A I2 6 A

15. Calculate the Currents
L1 L2
8A Is 8 A
S 8A I1 8 A
I2 8 A

16. Calculate the Currents
2A
L3
10 A Is 15 A
L2 I1 3A
L1 I2 10 A
S 15 A I3 2A

17. Calculate the Currents
L1 L2 L3
Is 4A
4A I1 4A
S I2 4A
I3 4A