Measurements of the quantized Hall resistance at the ETL

The quantized Hall resistance R/sub H/(4) of Si-MOSFETs has been measured in terms of Omega /sub ETL/ by the use of a recently constructed measurement system at the Electrotechnical Laboratory, Japan. The time variation of the 1- Omega /sub ETL/ resistance standard relative to the QHR is traced. A potentiometric method is used to compare R/sub H/(4) with a reference resistor of nominal value 6453.2- Omega . A cryogenic current comparator system is used to link the 6453.2- Omega resistor to Omega /sub ETL/. The estimated overall uncertainty is 5*10/sup -8/. The experimental equipment and procedure are described in detail.<>