Mineral oxide insulated (MgO) thermoresistances.
PT 100 Ohm thermoresistances are made of materials whose resistance depends from temperature.
Platinum wired thermoresistances have a highly linear characteristic, which makes them fit in the temperature range -220°C to 850°C.
Less precise thermoresistances are made of Nickel. Their resistance can drift in time, their characteristic is little linear and range is limited to: -60°C to +180°C.
Housing bodies are in Nickel or AISI 304 stainless steel, though AISI 310, AISI 316 or PVC-enamelled bodies are also available for highly corrosive environments.
Conventional insulated thermoresistances.
Conventional insulation thermoresistances are manufactured to IEC or DIN specifications, consisting in a platinum or nickel wire coiled on a ceramic or glass insulating core.
Nominal resistance is 100 Ohm at 0°C.