ARRL Technician Practice Exam

What electrical component is used to oppose the flow of current in a DC circuit?

1. Capacitor

2. Inductor

3. Resistor

4. POTENTIOMETER

The correct answer is: Resistor

In a DC circuit, the component that is used to oppose the flow of current is a resistor. Resistors are specifically designed to limit the amount of current that can flow through a circuit by providing a specific amount of resistance, measured in ohms. This property makes them essential for controlling current levels and protecting sensitive components from excessive current. The fundamental role of a resistor is rooted in Ohm's Law, which states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. Thus, when voltage is applied to a resistor, it creates a voltage drop across the resistor, which reduces the current in the circuit. While capacitors and inductors are vital components in electrical circuits, they serve different purposes. Capacitors store electrical energy temporarily and influence the flow of current by introducing reactance, especially in AC circuits. Inductors, on the other hand, store energy in a magnetic field when current flows through them and also provide reactance. A potentiometer is a variable resistor that can adjust resistance within a circuit but fundamentally operates on the same principle as any standard resistor. In summary, resistors are the primary components that oppose current flow in DC circuits, making them crucial