Which term describes a resistor whose resistance can be changed by adjusting the portion of the resistor the current travels through?

Which term describes a resistor whose resistance can be changed by adjusting the portion of the resistor the current travels through?

• A. Variable resistor
• B. Fixed resistor
• C. Fixed value resistor
• D. Potentiometer

Answer: (A)

Being able to adjust resistance means the device lets you change how much of the resistive material the current travels through. For a uniform resistor, the resistance is proportional to the length of the path the current takes. So by moving a contact along the resistor to pick a different portion of the track, you change the length the current flows through and thus change the resistance. This is the hallmark of a variable resistor. A potentiometer is a specific type of variable resistor with a sliding contact, and it’s often used as a voltage divider. When used as a two-terminal component, it also behaves as a variable resistor, but its main common use is as a three-terminal device for dividing voltage. The other options describe resistors whose resistance is fixed and does not change.

Being able to adjust resistance means the device lets you change how much of the resistive material the current travels through. For a uniform resistor, the resistance is proportional to the length of the path the current takes. So by moving a contact along the resistor to pick a different portion of the track, you change the length the current flows through and thus change the resistance. This is the hallmark of a variable resistor.

A potentiometer is a specific type of variable resistor with a sliding contact, and it’s often used as a voltage divider. When used as a two-terminal component, it also behaves as a variable resistor, but its main common use is as a three-terminal device for dividing voltage. The other options describe resistors whose resistance is fixed and does not change.