Sufficient powerful set of tools for analysing a

sufficient, powerful set of tools for analysing a large variety of electric
circuits
• These laws are formally known as Kirchhoff’s current law (KCL) and
Kirchhoff’s voltage law (KVL)

Kirchhoff’s Laws
- Kirchhoff’s first law is based on the law of conservation of charge
- Meaning, the algebraic sum of charges within a system cannot
change
- Kirchhoff’s Current Law (KCL) states that the algebraic sum of
currents entering a node (or a closed boundary) is zero

Kirchhoff’s Laws
Where is the number of branches connected to the node
and is the nth current entering (or leaving) the node

Kirchhoff’s Laws

Kirchhoff’s Laws
- Kirchhoff’s second law is based on the principle of conservation of
energy
- Kirchhoff’s Voltage Law (KVL) states that the algebraic sum of all
voltages around a closed path (or loop) is zero

Kirchhoff’s Laws
Expressed mathematically, KVL states that
Wherein is the number of branches (or voltages) in the loop and
is the nth voltage

Kirchhoff’s Laws
- KVL can be applied in both clockwise and counter clockwise direction.
Either way, the sum of the voltages around the loop is equivalent to
zero
- For non-source elements, voltage polarities should be assigned (if not
stated by the problem!)
- KVL can also be reinterpreted as

Kirchhoff’s Laws
- When voltage sources are connected in series, KVL can be applied to
obtain the total voltage

Example 6
For the circuit shown, find the voltages and

Example 7
For the circuit shown, find the voltages and

Example 8
For the circuit shown, find the voltages and