Managing Heat Loss Around a PI Heater for More Stable Operation

https://advanced-heat-elements.moderncairn.com/posts/ito-glass-heater-vs-conventional-heating-elements-key-differences

In sensors, a pi heater must deliver heat in a controlled way. It uses a thin resistive foil circuit laminated in polyimide film. One useful trait is fast response. Still, local hot spots can change the result