THE USE OF A SOLID STATE DC VOLTAGE TRANSPORT STANDARD TO TRANSFER THE DC VOLT IN A REGIONAL STANDARD CELL MAP PROGRAM

摘要

Many times the most significant errors in DC voltage MAPS are caused by changes that occur in saturated cells when they are transported. This was noted in a recent paper (1) by the BIPM/ Sevres, France, where degradations up to 1OO:1 were reported when saturated cells were used as transport standards, compared to their performance when used as reference standards in a fixed location and environment. The use of saturated cells as transport standards was also found to be the limiting factor by SRL, Inc. in a recent NCSL Region 2 MAP program completed in October, 1982, Five companies (Lockheed, Standard Reference Labs, Inc., RCA, Guildline, and Grumman) participated in this program.. In an effort to improve their transfer accuracy, Standard Reference Labs, Inc. will use a solid state DC voltage transport standard in a second MAP program scheduled for October, 1983. The SRL ovenized standard will be the same unit recently used in an international round robin (2) which demonstrated that solid state standards of EMF can perform as transport standards to a precision significantly better than 1ppm at the reference diode voltage level. The main difference will be that the 1.01814 volt reference level will be used in the second region 2 MAP program. This reference level is a resistively stepped down voltage value from the 10 volt reference output level which in turn is derived from the reference diode reference level used in the international round robin. The other four participating companies will use saturated standard cell banks as their transport standards. The results of solid state standard transfer data will be presented in this paper.