Young Gyun Kim

All-around dual source impedance bridge

Two terminal dual source impedance bridge was configured using commercial voltage calibrators. The bridge performance was evaluated by measuring 1 to 1 resistance ratio at 1 kHz using 1 kΩ and 10 kΩ resistors. The same bridge was used for the resistance (R) to the inductor (L) and the capacitor (C) ratio measurements by adjusting the phase between the voltage sources. Then, the AC resistance value was found from the R : C ratio. This simple two terminal dual source impedance bridge proved its reliable and versatile measurement capability.

Ac/dc magnetic flux density standard systems at KRISS

The ac/dc magnetic-flux-density (MFD) standard systems were developed for the calibration of magnetometers and the test of sensors and materials. The dc MFD is maintained to cover the range from 20 µT to 2.5 T with the expanded uncertainties (k = 2) from 4 µT/T to 80 µT/T. The expanded uncertainty (k = 2) of ac MFD standard is 0.2 % in the range of 1 Hz to 20 kHz. We had been participated in international key comparison to achieve the equality and the mutual agreement between standard institutes for the results of calibrations and tests.

Power calibration system based on Josephson sampling voltmeter

This paper describes system setup, based on a Josephson sampling voltmeter for precision power calibration. The waveforms generated by voltage and current sources, which are applied to a power meter under test, are transformed to 1-V level voltage signals and measured by a single Josephson voltmeter with a uncertainty (k = 2) less than 0.5 μV/V.

Magnetic flux density standard for low magnetic field at KRISS

The low magnetic field standard system contains a precision solenoid, Cs-He precision magnetometer, and 3-component compensation of the Earths magnetic field (EMF). The solenoid produces a standard field which is uniform at better than 0.3 ppm within /spl plusmn/2 cm of the center. The EMF is automatically compensated to 0.1 nT. The standard serves the calibration of magnetometers in the range below 1 mT with 1 nT resolution.

Bilateral comparison of DC magnetic flux density between NML-SIRIM and KRISS (P1-APMP.EM-S13)

A bilateral comparison of magnetic flux density has been performed between Korea Research Institute of Standards and Science (KRISS) and National Metrology Laboratory, SIRIM (NML-SIRIM), and registered as APMP.EM-S13 in the BIPM key comparison database. This comparison was piloted by KRISS and the results of the NML-SIRIM were linked to those of the CCEM.M-K1 key comparison through KRISS. The mean value of the coil constant and the uncertainty of the mean reported by both laboratories were used in the calculation of the degree of equivalence (DOE). Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).