They are popular because they are popular, which is a circular argument that suits a pie chart. But there are some serious downsides to using the humble pie.

Graphic Calculator Co. Description This circular slide chart consists of two plastic discs of equal size held together at the center by a metal rivet. The bottom disc is white, with a green ...

The CT5100 circular chart recorder is capable of measuring and displaying up to two process variables. Users can choose from a variety of programmable inputs.