What electrical component opposes the flow of current in a DC circuit?
The correct answer is B: Resistor. A resistor is the electrical component that opposes the flow of current in a DC circuit. Resistance is the property that limits current flow, and resistors are components designed to provide specific resistance values.
Resistors are fundamental components in electronics. They oppose current flow by converting electrical energy into heat. The amount of opposition is measured in ohms (Ω). Resistors are used to limit current, divide voltage, provide bias voltages, and many other functions. In DC circuits, resistors provide constant opposition to current flow, following Ohm's Law (E = I × R). Understanding resistors is essential for all electronics work.
Exam Tip
Resistor opposes DC current. Remember: Resistors are components that oppose the flow of current in DC circuits by providing resistance, measured in ohms.
Memory Aid
"**R**esistor = **R**esists **C**urrent (think 'R = RC')"
Real-World Application
You're building a simple LED circuit. You need to limit the current to protect the LED. You add a resistor - it opposes the current flow, limiting it to a safe value. The resistor converts excess electrical energy into heat, protecting your LED while allowing proper operation.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Inductors oppose changes in current (AC reactance), not steady DC current flow. Inductors have very low resistance to DC current.
Option C: Incorrect. An inverter converts DC to AC, it doesn't oppose current flow in a DC circuit. It's a power conversion device.
Option D: Incorrect. Transformers transfer AC energy between circuits, they don't oppose DC current flow. Transformers don't work with DC.
题目解析
The correct answer is B: Resistor. A resistor is the electrical component that opposes the flow of current in a DC circuit. Resistance is the property that limits current flow, and resistors are components designed to provide specific resistance values. Resistors are fundamental components in electronics. They oppose current flow by converting electrical energy into heat. The amount of opposition is measured in ohms (Ω). Resistors are used to limit current, divide voltage, provide bias voltages, and many other functions. In DC circuits, resistors provide constant opposition to current flow, following Ohm's Law (E = I × R). Understanding resistors is essential for all electronics work.
考试技巧
Resistor opposes DC current. Remember: Resistors are components that oppose the flow of current in DC circuits by providing resistance, measured in ohms.
记忆口诀
**R**esistor = **R**esists **C**urrent (think 'R = RC')
实际应用示例
You're building a simple LED circuit. You need to limit the current to protect the LED. You add a resistor - it opposes the current flow, limiting it to a safe value. The resistor converts excess electrical energy into heat, protecting your LED while allowing proper operation.
错误选项分析
Option A: Incorrect. Inductors oppose changes in current (AC reactance), not steady DC current flow. Inductors have very low resistance to DC current. Option C: Incorrect. An inverter converts DC to AC, it doesn't oppose current flow in a DC circuit. It's a power conversion device. Option D: Incorrect. Transformers transfer AC energy between circuits, they don't oppose DC current flow. Transformers don't work with DC.
知识点
Resistor, Resistance, Current opposition, DC circuit
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.