Conservation laws

Definition

Conservation laws state that certain physical quantities remain constant within an isolated system. In circuits, the primary conservation laws are Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL).

5 Must Know Facts For Your Next Test

1. Kirchhoff's Voltage Law (KVL) states that the sum of all electrical potential differences around a closed loop is zero.
2. Kirchhoff's Current Law (KCL) states that the total current entering a junction equals the total current leaving the junction.
3. Conservation of charge underlies KCL, ensuring charge is neither created nor destroyed at a junction.
4. Conservation of energy underlies KVL, ensuring energy supplied equals energy dissipated in a closed loop.
5. Both KVL and KCL can be used to solve complex circuits by setting up systems of linear equations.

Review Questions

• What does Kirchhoff's Voltage Law state about a closed loop in a circuit?
• How does Kirchhoff's Current Law apply to currents at a junction?
• Why are conservation laws essential when analyzing electrical circuits?

Related terms

Kirchhoff's Voltage Law (KVL): The principle that the algebraic sum of all voltages around any closed circuit is zero.

Kirchhoff's Current Law (KCL): The principle stating that the total current entering a junction must equal the total current leaving the junction.

Ohm's Law:

$V = IR$, describing the relationship between voltage ($V$), current ($I$), and resistance ($R$).