What is the purpose of a fuse in an electrical circuit?
The correct answer is B: To remove power in case of overload. The purpose of a fuse in an electrical circuit is to remove power in case of overload. When current exceeds the fuse rating, the fuse element melts (blows), opening the circuit and stopping current flow. This protects equipment and wiring from damage due to excessive current. For amateur radio operators, fuses are essential safety devices that prevent fires and equipment damage. Understanding fuse function helps when troubleshooting and maintaining equipment.
Exam Tip
Fuse purpose = remove power in overload. Think 'F'use = 'F'ails (blows) to 'F'ix overload. Protects against excessive current by opening the circuit. Not for ripple, not for shock protection - just overload protection.
Memory Aid
"Fuse purpose = remove power in overload. Think 'F'use = 'F'ails (blows) to protect. Opens circuit when current exceeds rating, preventing fires and equipment damage. Essential safety device."
Real-World Application
Your power supply has a 10-amp fuse. If a short circuit occurs and draws 50 amps, the fuse blows immediately, opening the circuit and stopping the current. This prevents the wiring from overheating and starting a fire. Without the fuse, the excessive current could cause serious damage or fire.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Fuses don't prevent power supply ripple - that's what capacitors and filters do. Fuses protect against overcurrent, not voltage variations.
Option C: Incorrect. Fuses don't limit current to prevent shocks - they protect against overcurrent that could cause fires. Shock protection comes from proper grounding and insulation.
Option D: Incorrect. Since A and C are not fuse functions, 'all of the above' cannot be correct. Only overload protection is the primary fuse function.
题目解析
The correct answer is B: To remove power in case of overload. The purpose of a fuse in an electrical circuit is to remove power in case of overload. When current exceeds the fuse rating, the fuse element melts (blows), opening the circuit and stopping current flow. This protects equipment and wiring from damage due to excessive current. For amateur radio operators, fuses are essential safety devices that prevent fires and equipment damage. Understanding fuse function helps when troubleshooting and maintaining equipment.
考试技巧
Fuse purpose = remove power in overload. Think 'F'use = 'F'ails (blows) to 'F'ix overload. Protects against excessive current by opening the circuit. Not for ripple, not for shock protection - just overload protection.
记忆口诀
Fuse purpose = remove power in overload. Think 'F'use = 'F'ails (blows) to protect. Opens circuit when current exceeds rating, preventing fires and equipment damage. Essential safety device.
实际应用示例
Your power supply has a 10-amp fuse. If a short circuit occurs and draws 50 amps, the fuse blows immediately, opening the circuit and stopping the current. This prevents the wiring from overheating and starting a fire. Without the fuse, the excessive current could cause serious damage or fire.
错误选项分析
Option A: Incorrect. Fuses don't prevent power supply ripple - that's what capacitors and filters do. Fuses protect against overcurrent, not voltage variations. Option C: Incorrect. Fuses don't limit current to prevent shocks - they protect against overcurrent that could cause fires. Shock protection comes from proper grounding and insulation. Option D: Incorrect. Since A and C are not fuse functions, 'all of the above' cannot be correct. Only overload protection is the primary fuse function.
知识点
Fuses, Overload protection, Circuit protection, Electrical safety
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.