Electrical current is measured in which of the following units?
The correct answer is D: Amperes. Electrical current is measured in amperes (often abbreviated as 'amps' or 'A'). Current is the flow of electric charge (electrons) through a conductor, and the ampere is the standard unit for measuring this flow rate.
One ampere represents one coulomb of charge flowing past a point per second. Current is one of the fundamental electrical quantities, along with voltage and resistance. When you see specifications like '12 amperes' or '5A', that's referring to electrical current. Understanding current is essential for amateur radio, as you need to know how much current your equipment draws to properly size power supplies, fuses, and wiring.
Exam Tip
Current = Amperes. Remember: Electrical current is measured in amperes (A). Think 'Current flows in Amperes'.
Memory Aid
"**C**urrent = **A**mperes (think 'C = A' = Current = Amperes)"
Real-World Application
Your transceiver draws 12 amperes when transmitting at full power. This means 12 amperes of current flow through the power wires from your battery to the transceiver. You need to ensure your power supply and wiring can handle at least 12 amperes. If you use wire that's too thin, it might overheat with this much current.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Volts measure voltage (electrical pressure), not current. Voltage and current are different quantities.
Option B: Incorrect. Watts measure power (the rate of energy use), not current. Power = Voltage × Current.
Option C: Incorrect. Ohms measure resistance (opposition to current flow), not current itself.
题目解析
The correct answer is D: Amperes. Electrical current is measured in amperes (often abbreviated as 'amps' or 'A'). Current is the flow of electric charge (electrons) through a conductor, and the ampere is the standard unit for measuring this flow rate. One ampere represents one coulomb of charge flowing past a point per second. Current is one of the fundamental electrical quantities, along with voltage and resistance. When you see specifications like '12 amperes' or '5A', that's referring to electrical current. Understanding current is essential for amateur radio, as you need to know how much current your equipment draws to properly size power supplies, fuses, and wiring.
考试技巧
Current = Amperes. Remember: Electrical current is measured in amperes (A). Think 'Current flows in Amperes'.
记忆口诀
**C**urrent = **A**mperes (think 'C = A' = Current = Amperes)
实际应用示例
Your transceiver draws 12 amperes when transmitting at full power. This means 12 amperes of current flow through the power wires from your battery to the transceiver. You need to ensure your power supply and wiring can handle at least 12 amperes. If you use wire that's too thin, it might overheat with this much current.
错误选项分析
Option A: Incorrect. Volts measure voltage (electrical pressure), not current. Voltage and current are different quantities. Option B: Incorrect. Watts measure power (the rate of energy use), not current. Power = Voltage × Current. Option C: Incorrect. Ohms measure resistance (opposition to current flow), not current itself.
知识点
Electrical current, Amperes, Current measurement, Electrical units
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.