Here is an easy way to implement automatic temperature control for your next project. The web site includes the schematic, parts list, PCB artwork, and application examples.

The heart of the circuit is the LM35DZ temperature sensor which is factory-calibrated in the Celsius (or Centigrade) scale with a linear Degree->Volt conversion function. The output voltage (at pin 2) changes linearly with temperature from 0V (0oC) to 1000mV (100oC).