Which element of a vacuum tube regulates the flow of electrons between cathode and plate?
The correct answer is A: Control grid. The element of a vacuum tube that regulates the flow of electrons between cathode and plate is the control grid. The control grid's voltage controls electron flow, allowing signal amplification. For amateur radio operators, this is how vacuum tubes work. Understanding this helps when using tube amplifiers.
Exam Tip
Regulates electron flow in tube = control grid. Think 'C'ontrol 'G'rid = 'C'ontrols 'G'rid voltage controls flow. Control grid's voltage regulates electron flow between cathode and plate. Not suppressor grid, not screen grid, not trigger electrode - just control grid.
Memory Aid
"Regulates electron flow in tube = control grid. Think 'C'ontrol 'G'rid = 'C'ontrols 'G'rid. Control grid's voltage regulates electron flow between cathode and plate. Primary control element in vacuum tubes."
Real-World Application
A vacuum tube amplifier: The control grid receives the input signal. By varying the control grid voltage, you control the electron flow from cathode to plate, amplifying the signal. The control grid is the primary control element - its voltage directly regulates electron flow.
Key Concepts
Why Other Options Are Wrong
Option B (Suppressor grid): Incorrect. Suppressor grid suppresses secondary emission, it doesn't regulate main electron flow. Control grid is the primary control element.
Option C (Screen grid): Incorrect. Screen grid reduces grid-to-plate capacitance, it doesn't regulate electron flow. Control grid is the primary control element.
Option D (Trigger electrode): Incorrect. Trigger electrode isn't a standard vacuum tube element - that's more like a thyratron. Control grid is the standard control element.
题目解析
The correct answer is A: Control grid. The element of a vacuum tube that regulates the flow of electrons between cathode and plate is the control grid. The control grid's voltage controls electron flow, allowing signal amplification. For amateur radio operators, this is how vacuum tubes work. Understanding this helps when using tube amplifiers.
考试技巧
Regulates electron flow in tube = control grid. Think 'C'ontrol 'G'rid = 'C'ontrols 'G'rid voltage controls flow. Control grid's voltage regulates electron flow between cathode and plate. Not suppressor grid, not screen grid, not trigger electrode - just control grid.
记忆口诀
Regulates electron flow in tube = control grid. Think 'C'ontrol 'G'rid = 'C'ontrols 'G'rid. Control grid's voltage regulates electron flow between cathode and plate. Primary control element in vacuum tubes.
实际应用示例
A vacuum tube amplifier: The control grid receives the input signal. By varying the control grid voltage, you control the electron flow from cathode to plate, amplifying the signal. The control grid is the primary control element - its voltage directly regulates electron flow.
错误选项分析
Option B (Suppressor grid): Incorrect. Suppressor grid suppresses secondary emission, it doesn't regulate main electron flow. Control grid is the primary control element. Option C (Screen grid): Incorrect. Screen grid reduces grid-to-plate capacitance, it doesn't regulate electron flow. Control grid is the primary control element. Option D (Trigger electrode): Incorrect. Trigger electrode isn't a standard vacuum tube element - that's more like a thyratron. Control grid is the standard control element.
知识点
Vacuum tube, Control grid, Electron flow, Tube operation
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.