Kirchhoff’s Voltage Law (KVL)

Kirchhoff’s Voltage Law (KVL)

Kirchhoff’s Voltage Law (KVL): At any instant sum of all voltage rises and voltage drops around a loop must be equal to all voltage drops across that loops.

Mathematically KVL can be expressed as

·         KVL is the consequence of law conservation of energy.

·         Work done to move a charge across a loop is zero.

Applying KVL:

·         Label Branch voltages with polarities.

·         Apply KVL to loop clockwise or counter clockwise.

For example:

·         If a voltage is unknown assume a polarity

·         Solve equations to find polarity

·         Positive polarity means we assumed correct polarity otherwise negative sign shows that we assumed we assumed false polarity.

Solved Problem:

If V₁ = 7V and V₃ = 9V What Is V₂

In Loop X₁X₂X₃

V₁ + V₂ = V₃

V₂ = V₃ - V₁

V₂ = 9V-7V

V₂ = 2V