What type of resistors are used to select and adjust the amount of total resistance applied to a circuit?

• A. Variable resistors
• B. Fixed resistors
• C. Power resistors
• D. Thermistors

Answer: (A)

The ability to set and adjust the total resistance in a circuit is provided by a variable resistor. This type includes devices like potentiometers and rheostats, which you can turn or slide to change the resistance value while the circuit is in use. That adjustability lets you fine-tune current flow, voltage levels, or signal levels for calibration, control, or tuning purposes.

Fixed resistors have a single, unchangeable value, so they don’t allow adjustment once placed in the circuit. Power resistors are built to handle higher current or voltage, but they’re still typically fixed in value unless they’re a specialized adjustable type. Thermistors change resistance in response to temperature, so they’re used for sensing or compensation rather than deliberate manual adjustment of total circuit resistance.