Physics · Ch 11 — Electric Current Through Conductors
Rheostat
Rheostat
A RHEOSTAT (Fig. 11.8) is an adjustable resistor -- a resistor whose effective resistance can be varied continuously by hand -- used wherever a circuit needs the current or resistance to be adjusted in use, rather than fixed once and for all at the time of manufacture. Its resistive element may be made of a metal wire or ribbon wound on a former, a carbon film, or even a conducting liquid, depending on the specific application and power rating needed. …
What this figure shows. A drawing of a rheostat: a long cylindrical resistive element (a coil of resistance wire wound around an insulating tube, or an equivalent resistive strip) mounted horizontally with two FIXED terminals at its ends, plus a THIRD terminal attached to a sliding contact (a wiper arm) that can be moved continuously along the length of the resistive element by hand. Moving the slider changes the length of resistive element included in the circuit between the slider terminal and either fixed end, thereby continuously varying the resista …