# Influence of Adaptor on the Calibration of Inductance Standards

• Kassim, Dewi Mohd (University of Science and Technology, (UST)) ;
• Kim, Dan Bee (Korea Research Institute of Standards and Science, (KRISS)) ;
• Kim, Wan-Seop (Center for Electricity & Magnetism, Korea Research Institute of Standards and Science, (KRISS))
• Received : 2017.12.11
• Accepted : 2018.01.02
• Published : 2018.03.01

#### Abstract

Influence of the adaptors on the calibration of $100{\mu}H$ inductance standard was studied as a function of torque, applied when tightening the standard inductor terminal with the adaptor. Two different homemade adaptors of BPO gold-plated brass (BPO-Au) and banana-copper (BN-Cu) were made for the connection between the LCR meter and the inductance standard. The measured inductance (L) of the standard inductor and the contact resistance ($R_C$) between the adaptor and the standard inductor terminal showed exponential decreases against the torque increase from $25cN{\cdot}m$ to $150cN{\cdot}m$. The measured L and the calculated equivalence series resistance ($R_S$) were dependent on the adaptor type as well as on the $R_C$. The results of the adaptor analysis imply that the BPO-Au adaptor with the lower $R_C$ is more suitable for the inductance calibration. The calculated inductance of $99.956{\mu}H$ corrected by subtraction of the adaptor inductance and the contact resistance contributions from the measured value using the BPO-Au adaptor agreed well with the certificate ($99.948{\mu}H$) of the PTB within the measurement uncertainty of $140{\mu}H/H$.

#### Acknowledgement

Grant : Development of Electro-Magnetic Measurement Standards and Application Technologies

Supported by : Korea Research Institute of Standards and Science

#### References

1. B. P. Kibble, "For Terminal-Pair to Anything Else," National Physical Laboratory, UK, 1999.
2. B. P. Kibble and G. H. Rayner, Coaxial AC Bridges, Adam Hilger Ltd, UK: 1984, pp. 4, pp. 83-86.
3. The General Radio Experimenter, "A Close Look at Connection Errors in Capacitance Measurements," vol. 33, no. 7, 1959.
4. The General Radio Experimenter, "Connection Errors in Inductance Measurement," vol. 34, no. 10, 1960.
5. QuadTech, "Building the Perfect Component Test Fixture," Application Note, no. 035094, 2000.
6. IET LABS, INC., http://www.ietlabs.com/1482.html, 2003.
7. QuadTech, "What Voltage and Current is Applied to the Unknown," Application Note, no. 035050/A3, 2003.
8. QuadTech, "Series & Parallel Impedance Parameters and Equivalent Circuits," Application Note, no. 035010, 2003.
9. QuadTech, "A Guide to LCR Measurements," Application Note no. 035001, 2003.
10. M. K. Dewi, D. B. Kim and W. S. Kim, "Influence of Adaptor on the calibration of Inductance Standards," presented at 21st IMEKO TC4 International Symposium, 2016.
11. F. Wenner. G. W. Nusbaum, B. C. Cruickshanks, "Note on the Electrical Resistance of Contacts between Nuts and Bolts, Bureau of Standards," in Journals of Research, 1930.