Understanding Voltage, Resistance, and Power in a PI Heater Circuit

https://thin-heater-technology.brightsora.com/posts/how-to-prevent-uneven-heating-in-a-glass-heater-application

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