A COMPUTERIZED MODEL OF VACUUM THERMOCOUPLE PERFORMANCE

Heat flow equations for vacuum thermocouples (VTC) were computerized in order to evaluate the effects of parameter changes. The steady state case demonstrates strong dependence on thermal conductivity versus temperature. Radiation as well as conductive losses through the partial vacuum become evident in the 5-mA type. The computer results checked very closely to Widdis [1], yet measured outputs in mV were 30 to 40% lower in the 5-mA types, and this discrepancy was major a incentive to carry on this work. Widdis [1], Inglis [4], and others have covered the responses of VTC's in some detail, but their emphasis was more focused on understanding the causes of ac/dc transfer error rather than quantifying the effects of the parameters to design and build VTC's.