A square plate of copper metal can be used as a crude variable resistor by making suitable choices of the places to attach leads that carry current to and from the plate.

(a) Current enters at A and exits at B.
(b) Current enters at A and exits at C.
(c) Current enters at A and exits at O.
(d) Current enters at A and exits at B and D, with the wires leaving those points joined together.

Transcribed Image Text:

R B A 0 C D