New designs for high-resistance standard resistors

Discussed are recent efforts undertaken at the National Institute of Standards and Technology (NIST) to create a new set of high-resistance standards (specifically in the 10 MΩ to 100 MΩ range) using newer, more stable film-type resistors. The history of film-type resistors in high-resistance standards is briefly reviewed. Also examined are the improvements made upon similar resistance standard implementations done by the Instituto Nacional de Tecnología Industrial (INTI) in Argentina. The new NIST standards use a guarded, highly resistive backbone to reduce leakage currents. Promising results, including reduced settling time and improved stability, are presented.