RfJ is the resistance at TOJ and is an experimental constant that can have a value between 3500 and 4500 degrees Kelvin, What this all means is that a graph like the one in Fig. 1 will result. This shows how the resistance of a thermistor can vary with temperature; K is the resistance and

T is the temperature. In practice it is best to determine this relation experimentally rather than try to depend upon mathematical calculations.

Physically, thermistors are made by compressing mixtures of compounds, usually oxides oi manganese, cobalt, calcium, uranium, iron, zinc, titanium, aluminum, and magnesium. ! his starts out in a powder form, and the material can be formed into rods, beads, or discs, by a process called sintering. This is merely a process of forming a blob of material under high pressure arid temperature,- Wire leads can be attached to the fTS

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