Resistor & Rheostat

Resistor(電阻器)

Resistor(電阻器)是具有已知電阻的裝置，用來調節流過電路的電流大小。
指會將電能轉化為其他能量（多為熱能）的元件。跟據歐姆定律 (ohms law) V=IR，電阻器能改變電路的電壓和電流。

Rheostat (變阻器)

Rheostat (變阻器)是可以調較電阻值的電阻器。例如滑線變阻器便是主要由線圈和滑動觸頭組合而成，將滑動觸頭移動，便可以改動連入電路內的導線長度，使電阻得以調較。

滑線變阻器是學校實驗室常用的變阻器，適合電路的電流較大時使用。

This is the simplest way of using a variable resistor. Two terminals are used: one connected to an end of the track, the other to the moveable wiper. Turning the spindle changes the resistance between the two terminals from zero up to the maximum resistance.
Rheostats are often used to vary current, for example to control the brightness of a lamp or the rate at which a capacitor charges.

Resistor 有固定的 resistance (電阻數值) ,Rheostat 的 resistance (電阻數值) 是可變的。