Which of the following pairs are the two general types of resistors?

• A. Conductor / variable
• B. Fixed / variable
• C. Variable / adjustable
• D. Fixed / conductor

Answer: (B)

Resistors come in two general types: fixed and variable. A fixed resistor has a single, unchanging resistance value chosen for a specific function in the circuit, providing stable current and voltage drops. A variable resistor is designed to be adjusted, letting you change the resistance to tune the circuit’s behavior—examples include potentiometers used as voltage dividers and rheostats used to vary current. The other options aren’t standard classifications in resistor types—conductors aren’t resistors, and while “adjustable” is essentially the same idea as variable, the common pairing is fixed and variable.