What portion of the AC cycle is converted to DC by a half-wave rectifier?
The correct answer is B: 180 degrees. The portion of the AC cycle converted to DC by a half-wave rectifier is 180 degrees. A half-wave rectifier conducts during one half of the AC cycle (180°), blocking the other half. For amateur radio operators, this explains half-wave operation. Understanding this helps when analyzing rectifier circuits.
Exam Tip
Half-wave rectifier converts = 180 degrees of AC cycle. Think 'H'alf-'W'ave = 'H'alf cycle = '1'80 degrees. Half-wave rectifies one half of AC cycle (180°), blocking the other half. Not 90°, not 270°, not 360° - just 180°.
Memory Aid
"Half-wave rectifier converts = 180 degrees of AC cycle. Think 'H'alf-'W'ave = 'H'alf cycle = '1'80 degrees. Half-wave rectifies one half of AC cycle, blocking the other half. Uses only half the AC power."
Real-World Application
A half-wave rectifier: During the positive half of the AC cycle (0-180°), the diode conducts and rectifies. During the negative half (180-360°), the diode blocks. Half-wave converts 180 degrees of the AC cycle to DC, using only half the available power.
Key Concepts
Why Other Options Are Wrong
Option A (90 degrees): Incorrect. 90 degrees is one quarter cycle - half-wave rectifies one half (180°), not one quarter. 90° is too small.
Option C (270 degrees): Incorrect. 270 degrees is three quarters - half-wave rectifies one half (180°), not three quarters. 270° is too much.
Option D (360 degrees): Incorrect. 360 degrees is the full cycle - half-wave only rectifies one half (180°), not the full cycle. 360° would be full-wave.
题目解析
The correct answer is B: 180 degrees. The portion of the AC cycle converted to DC by a half-wave rectifier is 180 degrees. A half-wave rectifier conducts during one half of the AC cycle (180°), blocking the other half. For amateur radio operators, this explains half-wave operation. Understanding this helps when analyzing rectifier circuits.
考试技巧
Half-wave rectifier converts = 180 degrees of AC cycle. Think 'H'alf-'W'ave = 'H'alf cycle = '1'80 degrees. Half-wave rectifies one half of AC cycle (180°), blocking the other half. Not 90°, not 270°, not 360° - just 180°.
记忆口诀
Half-wave rectifier converts = 180 degrees of AC cycle. Think 'H'alf-'W'ave = 'H'alf cycle = '1'80 degrees. Half-wave rectifies one half of AC cycle, blocking the other half. Uses only half the AC power.
实际应用示例
A half-wave rectifier: During the positive half of the AC cycle (0-180°), the diode conducts and rectifies. During the negative half (180-360°), the diode blocks. Half-wave converts 180 degrees of the AC cycle to DC, using only half the available power.
错误选项分析
Option A (90 degrees): Incorrect. 90 degrees is one quarter cycle - half-wave rectifies one half (180°), not one quarter. 90° is too small. Option C (270 degrees): Incorrect. 270 degrees is three quarters - half-wave rectifies one half (180°), not three quarters. 270° is too much. Option D (360 degrees): Incorrect. 360 degrees is the full cycle - half-wave only rectifies one half (180°), not the full cycle. 360° would be full-wave.
知识点
Half-wave rectifier, 180 degrees, AC cycle, Rectification
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.