Recently Temperature measurement and control is a major requirement in most process industries that is, those industries that handle and convert gases, liquids, and bulk solids into products. Chemical, petroleum, petrochemical, polymer, plastic and larger segments of metallurgical and food processing industries, are examples. Chemical reactions, material separation, distillation, drying, evaporation, absorption, crystallization, Baking, extrusion, and thermal therapies are processes that normally occur at controlled temperatures. Typical temperature control loops employ the popular proportional plus integral plus derivative (PID) control algorithm. However, there are many control loops that use the ON-OFF control algorithm. It is well known that ON-OFF control is a simple, time optimal control strategy whose application is made easier by micro-controllers combined with modern solid-state switching devices such as Thyristors, Diacs, and Triacs