What type of component is often used as an adjustable volume control?
The correct answer is C: Potentiometer. A potentiometer is the type of component often used as an adjustable volume control. Potentiometers are variable resistors with three terminals that allow you to adjust resistance, making them ideal for volume controls.
Potentiometers (pots) are variable resistors with a rotating or sliding contact that moves along a resistive element. They have three terminals: two end terminals and a wiper (center terminal). As you turn the knob, the wiper moves, changing the resistance between the wiper and each end terminal. This makes them perfect for volume controls, tone controls, and any application where you need to adjust a signal level. They're commonly found in audio equipment, radios, and test instruments.
Exam Tip
Potentiometer = Adjustable volume control. Remember: Potentiometers are variable resistors with three terminals, perfect for volume controls and other adjustable applications.
Memory Aid
"**P**otentiometer = **V**olume **C**ontrol (think 'P = VC')"
Real-World Application
You're operating your transceiver and want to adjust the audio volume. You turn the volume knob - that's a potentiometer. As you rotate it, the resistance changes, adjusting the signal level to your speaker. The potentiometer gives you smooth, continuous control over the volume level.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Fixed resistors have a constant resistance value that cannot be adjusted. They're not suitable for volume controls which need to be adjustable.
Option B: Incorrect. Power resistors are designed to handle high power, but they're typically fixed value, not adjustable. They're not used for volume controls.
Option D: Incorrect. Transformers transfer AC energy between circuits, they don't provide adjustable resistance for volume control.
题目解析
The correct answer is C: Potentiometer. A potentiometer is the type of component often used as an adjustable volume control. Potentiometers are variable resistors with three terminals that allow you to adjust resistance, making them ideal for volume controls. Potentiometers (pots) are variable resistors with a rotating or sliding contact that moves along a resistive element. They have three terminals: two end terminals and a wiper (center terminal). As you turn the knob, the wiper moves, changing the resistance between the wiper and each end terminal. This makes them perfect for volume controls, tone controls, and any application where you need to adjust a signal level. They're commonly found in audio equipment, radios, and test instruments.
考试技巧
Potentiometer = Adjustable volume control. Remember: Potentiometers are variable resistors with three terminals, perfect for volume controls and other adjustable applications.
记忆口诀
**P**otentiometer = **V**olume **C**ontrol (think 'P = VC')
实际应用示例
You're operating your transceiver and want to adjust the audio volume. You turn the volume knob - that's a potentiometer. As you rotate it, the resistance changes, adjusting the signal level to your speaker. The potentiometer gives you smooth, continuous control over the volume level.
错误选项分析
Option A: Incorrect. Fixed resistors have a constant resistance value that cannot be adjusted. They're not suitable for volume controls which need to be adjustable. Option B: Incorrect. Power resistors are designed to handle high power, but they're typically fixed value, not adjustable. They're not used for volume controls. Option D: Incorrect. Transformers transfer AC energy between circuits, they don't provide adjustable resistance for volume control.
知识点
Potentiometer, Variable resistor, Volume control, Adjustable resistance
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.