Component identification: What is the standard name for a two-terminal variable resistor used to adjust current or resistance in a circuit?

Introduction / Context:
Variable resistors are widely used to control current, adjust brightness, and set bias points. There are two common configurations: two-terminal and three-terminal. Knowing the correct names helps with schematic reading, part selection, and troubleshooting.

Given Data / Assumptions:

• We specifically need the name for a two-terminal variable resistor.
• No special sensing behavior (like temperature dependence) is implied.
• Mechanical adjustment via a sliding or rotating contact is assumed.

Concept / Approach:

A three-terminal variable resistor configured as a voltage divider is called a potentiometer. When the same device is wired to use only two terminals (one end and the adjustable arm), it functions as a variable series resistor and is called a rheostat. The term 'wiper' names the moving contact, not the component type. A thermistor is temperature-dependent; a photoresistor is light-dependent.

Step-by-Step Solution:

Verification / Alternative check:

Datasheets often describe a single part as 'potentiometer/rheostat' depending on wiring. In two-terminal mode, it is explicitly labeled for rheostat use.

Why Other Options Are Wrong:

Potentiometer implies three-terminal divider use. Thermistor varies with temperature, not a general mechanical adjuster. Wiper is the moving contact. Photoresistor varies with light, again not a generic mechanical variable resistor.

Common Pitfalls:

Using 'potentiometer' generically for all variable resistors, or calling the whole device a 'wiper'. Correct naming improves clarity in designs and documentation.

Final Answer:

rheostat