Automotive Electronics Practice Test

According to Kirchhoff's law, what is the voltage around a closed circuit equal to?

1. The sum of the resistances

2. The total current

3. The sum of the voltage drops across all the loads

4. The total power output

The correct answer is: The sum of the voltage drops across all the loads

According to Kirchhoff's voltage law, in a closed circuit, the algebraic sum of all voltages must equal zero. This means that the total voltage supplied by sources (like batteries or power supplies) in the circuit is equal to the sum of the voltage drops across all the loads (such as resistors, capacitors, and inductors) within that circuit. This relationship is crucial for analyzing electrical circuits, as it ensures that energy is conserved within the loop. Essentially, the energy supplied by the voltage source is completely converted into energy consumed by the loads in the circuit, resulting in no leftover voltage when the loop is completed. This principle allows engineers and technicians to predict circuit behavior and troubleshoot any issues effectively. In this context, focusing on the other options provides a clearer understanding of why the correct answer is centered on the sum of the voltage drops: the sum of resistances relates to Ohm's law but does not encapsulate the full relationship between voltage and current; the total current does not reflect voltage levels; and total power output pertains to energy consumption rather than the direct relationship between voltage and loads within a circuit. This underlines why the answer emphasizing the sum of voltage drops is the most accurate representation of Kirchhoff's voltage law.