The precise measurement
of conductivity of a semiconductor film such as polypyrrole (Ppy)
should be carried out by the four-point probe method; however, this
is difficult for classroom application. This article describes the
development of a new, convenient, handmade conductivity device from
inexpensive materials that can measure the conductivity of a
thin-film semiconductor. Lessons on using the handmade device were
conducted with high school students. The results show that the device
was useful and trouble free for high school students to determine the
electrical conductivity of Ppy.