I think I have correctly designed this very simple voltage divider circuit to indicate when a voltage potential reaches a certain level. Since I am an extreme novice, I thought I would ask for constructive criticism. If I am using a PTC device connected with a small resistor in series, I should be able to monitor the voltage between the two to establish the current state of the ptc resistor. Also, using a zener at this point, I should be able to connect that to a pic to be monitored without fear of over-loading the microcontroller. Does anyone disagree with this? All feedback is appreciated.