1. Kirchhoff’s Laws

2. Conservation of Energy
As electrons move through a circuit, they lose energy in the various loads they pass through
Energy cannot be created or destroyed
The total energy lost in the loads must equal the energy gained in the source
Charge is not created or destroyed and does not accumulate at any point in the circuit

3. Kirchoff’s Laws
Application of conservation laws to current and voltage in a circuit
Law of Voltage – around any complete path of a circuit, the sum of increases in potential is equal to the sum of decreases
Vo = V1 + V2 + V3 ….

4. Example
V1= 3V V2
V3= 5V
Vo=
12 v V4 V5

5. Law of Current
At any junction point in an electric circuit, the total current into the junction is equal to the total current out
Io = I1 + I2 + I3

6. Example
I1=2.5A I2
I3=4.0A
Io=12.5A

7. Solve for V1, V2, V3, Io, I1, I2, I3 R1=6 I1= Io V1 Vo= R2=10 V2 60V

8. Find Vo, V1, V2, V3, Io, I4, R1, R2 Io= I1=2A I2=4A I3=6A Vo= V1= V2=8
V3=
R1=
R2=
I4=

9. Find V1, V2, V3, I1, I2, I3 , R2 V1= Io=12A I1= I2= R1=8 R3= 3 V2=
Vo=120V
R2=
I3=