How does a switchmode voltage regulator work?
The correct answer is B: By varying the duty cycle of pulses input to a filter. How does a switchmode voltage regulator work is by varying the duty cycle of pulses input to a filter. Switchmode regulators vary duty cycle to control output. For amateur radio operators, this is important for power supply design. Understanding this helps when working with switching regulators.
Exam Tip
Switchmode voltage regulator works = by varying duty cycle of pulses input to filter. Think 'S'witchmode = 'S'witching 'D'uty cycle. Switchmode regulators vary duty cycle to control output. Not alternating output, not varying conductivity (linear), not Zener switching - just varies duty cycle.
Memory Aid
"Switchmode voltage regulator works = by varying duty cycle of pulses input to filter. Think 'S'witchmode = 'D'uty cycle. Switchmode regulators vary duty cycle to control output. Important for power supply design."
Real-World Application
A switchmode voltage regulator: It works by varying the duty cycle of pulses input to a filter. The switch turns on and off rapidly, and the duty cycle controls the average output voltage. This is how it works - varies duty cycle.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Alternating output between positive and negative voltages isn't switchmode - switchmode varies duty cycle. Alternating output isn't switchmode.
Option C: Incorrect. Varying conductivity of pass element isn't switchmode - that's linear regulator. Varying conductivity isn't switchmode.
Option D: Incorrect. Switching between two Zener reference voltages isn't switchmode - switchmode varies duty cycle. Zener switching isn't switchmode.
题目解析
The correct answer is B: By varying the duty cycle of pulses input to a filter. How does a switchmode voltage regulator work is by varying the duty cycle of pulses input to a filter. Switchmode regulators vary duty cycle to control output. For amateur radio operators, this is important for power supply design. Understanding this helps when working with switching regulators.
考试技巧
Switchmode voltage regulator works = by varying duty cycle of pulses input to filter. Think 'S'witchmode = 'S'witching 'D'uty cycle. Switchmode regulators vary duty cycle to control output. Not alternating output, not varying conductivity (linear), not Zener switching - just varies duty cycle.
记忆口诀
Switchmode voltage regulator works = by varying duty cycle of pulses input to filter. Think 'S'witchmode = 'D'uty cycle. Switchmode regulators vary duty cycle to control output. Important for power supply design.
实际应用示例
A switchmode voltage regulator: It works by varying the duty cycle of pulses input to a filter. The switch turns on and off rapidly, and the duty cycle controls the average output voltage. This is how it works - varies duty cycle.
错误选项分析
Option A: Incorrect. Alternating output between positive and negative voltages isn't switchmode - switchmode varies duty cycle. Alternating output isn't switchmode. Option C: Incorrect. Varying conductivity of pass element isn't switchmode - that's linear regulator. Varying conductivity isn't switchmode. Option D: Incorrect. Switching between two Zener reference voltages isn't switchmode - switchmode varies duty cycle. Zener switching isn't switchmode.
知识点
Switchmode voltage regulator, How it works, Varying duty cycle, Pulses input to filter
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.