Question T6A02
From subelement T6 - T6A
What type of component is often used as an adjustable volume control?
Why is this correct?
A potentiometer is correct because it's a variable resistor that allows you to adjust resistance by turning a knob or sliding a control. This changing resistance controls current flow, which directly affects volume levels in audio circuits. Fixed resistors (A) and power resistors (B) have unchanging values and can't be adjusted during operation. A transformer (D) changes voltage levels but doesn't provide the variable control needed for volume adjustment.
Memory tip
Look for the word 'adjustable' in questions—it's your key signal that you need a variable component. Fixed components can't be adjusted by the user, while variable components like potentiometers have controls (knobs, sliders) that change their electrical properties during operation.
Learn more
In practical amateur radio operation, potentiometers are everywhere: volume controls on transceivers, squelch adjustment knobs, and RF power output controls. They work by having a movable contact (wiper) that slides along a resistive element, creating different resistance values between the terminals. This variable resistance principle is fundamental to user controls in electronic equipment, allowing operators to fine-tune circuit behavior in real time.
Think about it
Why do you think audio volume can be controlled by varying resistance, and what would happen to the sound if you used a fixed resistor instead of a potentiometer?