Question T6A03
From subelement T6 - T6A
What electrical parameter is controlled by a potentiometer?
Why is this correct?
A potentiometer is a variable resistor that allows you to adjust resistance by turning a shaft or sliding a control. As you turn the knob, the resistance changes, which is why potentiometers are commonly used as volume controls in radios. Inductance is controlled by coils/inductors, capacitance by capacitors with conductive surfaces separated by insulators, and field strength relates to electromagnetic properties, not mechanical controls.
Memory tip
Remember the component's name gives it away: 'pot' + 'meter' literally means resistance meter that can be varied. When you see 'adjustable' or 'variable' paired with any electrical component, focus on what fundamental property that component type controls—resistors always control resistance.
Learn more
In amateur radio operation, potentiometers serve critical functions beyond volume control. They adjust squelch levels to eliminate weak signal noise, control transmit power output within authorized emission standards, and fine-tune antenna matching networks. Understanding that potentiometers provide continuously variable resistance helps explain why they're essential for precise adjustments in transceivers, where digital controls would be too coarse for optimal performance.
Think about it
Why do you think volume controls in radios use variable resistance rather than switching between fixed resistance values to adjust audio levels?