Which type of variable resistor has only two contacts?

Which type of variable resistor has only two contacts?

• A. Potentiometer
• B. Preset variable resistor
• C. Rheostat
• D. Dual on/off switch

Answer: (C)

A rheostat is a type of variable resistor designed specifically for controlling current. It typically consists of a resistive wire or track that can be adjusted to change resistance, allowing for the modulation of the electrical current flowing through a circuit. Rheostats commonly have only two contacts: one connected to one end of the resistive element and the other connected to the movable wiper that slides along the resistive element. By adjusting the wiper's position, the resistance can be varied, allowing control over the current. While potentiometers can also function as variable resistors, they typically have three terminals: one terminal connects to one end of the resistive track, another to the opposite end, and the third to the wiper. Similarly, while preset variable resistors may have two or three contacts, they often serve a different purpose, typically allowing for set-and-forget adjustments. Therefore, the defining characteristic of a rheostat is its two-contact configuration, suitable for applications where variable resistance is needed without the complexities that come with additional terminals.

A rheostat is a type of variable resistor designed specifically for controlling current. It typically consists of a resistive wire or track that can be adjusted to change resistance, allowing for the modulation of the electrical current flowing through a circuit. Rheostats commonly have only two contacts: one connected to one end of the resistive element and the other connected to the movable wiper that slides along the resistive element. By adjusting the wiper's position, the resistance can be varied, allowing control over the current.

While potentiometers can also function as variable resistors, they typically have three terminals: one terminal connects to one end of the resistive track, another to the opposite end, and the third to the wiper. Similarly, while preset variable resistors may have two or three contacts, they often serve a different purpose, typically allowing for set-and-forget adjustments. Therefore, the defining characteristic of a rheostat is its two-contact configuration, suitable for applications where variable resistance is needed without the complexities that come with additional terminals.