Hi Jay,

What do you want to know ? PRTs will work from certainly -70 to in excess of 400 C. You CAN push them higher, but there are problems with diffusion of the element holder into the PRT itself buggering up the reproducibility. We use a fairly simple Burr-Brown instrument amp to read them into a 7107 ADC, and we have spot calibrations at our critical temperatures, 40, 60 100, 150 C. For the ultimate readout, you need a transformer ratio arm bridge, or NPL bridge, then the uncertainties approach that of a triple point cell.

Beyond 400, you're back to thermocouples, but the very very best performance from them still give you uncertainties in the 0.2 deg C level, the standards themselves cannot be realised to better than that.

Steve