Define Kirchhoff's Voltage Law.

Kirchhoff's Voltage Law (KVL) states that the sum of the electrical potential differences around any closed loop or circuit is equal to zero. This principle is fundamental in circuit analysis as it reflects the conservation of energy within electrical circuits. According to KVL, when you traverse a complete circuit loop and add up all the voltages—considering voltage rises and drops—the total must balance out to zero.

This principle implies that the energy supplied by sources (like batteries) is used up by the components in the circuit (such as resistors, capacitors, etc.), ensuring that energy is conserved. In essence, all the voltage gains (from sources) and losses (across elements such as resistors) in a complete loop will always balance out, which is crucial for analyzing complex circuits.

The other definitions presented do not align with the essence of Kirchhoff's Voltage Law. While they relate to various aspects of electrical principles, they do not capture the distinctive nature of KVL, which specifically pertains to the measurement of voltage across a closed circuit loop.