A set of seven single junction thermal converter Micropotentiometers (μPots) has been constructed at the National Institute for Standards (NIS), Egypt. This set has been built to cover the low ac voltage ranges from 2 mV to 200 mV at frequencies from 40 Hz up to 20 kHz. The construction of the μPots set has been presented and an adopted calibration method has been performed as well. This method has been performed by means of a step-down procedure using a Digital Multi-Meter (DMM). The scaling procedures have been carried out in sequential steps starting from the calibration of the 200 mV-μpot by using DMM that is accurately calibrated at its 200 mV ac voltage range down to 2 mV-μPot. Furthermore, a new automatic calibration system has been established to achieve the scaling procedures. This system has been specially designed using Laboratory Virtual Instrument Engineering Workbench (LabVIEW) software to overcome the deficiencies of manual methods. The automatic calibration has been investigated of all mPots at different frequencies. The ac-dc differences for the μPots and their uncertainty evaluation from 2 mV to 200 mV at different frequencies from 40 Hz to 20 kHz have been determined.
 I. Budovsky, “A Micropotentiometer-Based System for Low-Voltage Calibration of Alternating Voltage Measurement Standards,” IEEE Transactions on Instrumentation and Measurement, Vol. 46, No. 2, 1997, pp. 356-360. doi:10.1109/19.571855
 H. Dintners, M. Klonz, A. Lerm, F. Vblklein and T. Weimann, “AC-DC-mV-Transfer with Highly Sensitive Thin-Film Multijunction Thermal Converters,” IEEE Transactions on Instrumentation and Measurement, Vol. IM-42, 1993, pp. 612-614.
 J. R. Kinard, D. X. Huang and D. B. Novotny, “Integrated Thin-Film Micropotentiometers,” IEEE Transactions on Instrumentation and Measurement, Vol. IM-44, No. 2, 1995, pp. 374-376. doi:10.1109/19.377856
 U. Pogliano, G. C. Bosco and M. Lanzillotti, “Generalized Automatic System for AC/DC Transfer, AC Voltage, and AC Current Measurements,” IEEE Transactions on Instrumentation and Measurement, Vol. 55, No. 5, 2006, pp. 1747-1751. doi:10.1109/TIM.2006.880958
 A. Haroutunian, M. Halawa, A. Hassan, R. Attyia and H. A. Mageed “Comparison of the Technical Performance for Different Designs of Single Junction Thermal Converters,” Cpem-2008 Boulder, USA, 2008.
 H. A. Mageed, A. F. Zobaa, A. Ghitas, M. H. A. Raouf, M. Sabry, A. H. A. Rahman and M. M. A. Aziz, “Electrical Performance Study of a Large Area Multicrystalline Silicon Solar Cell Using a Current Shunt and a μPotentiometer,” Engineering Transactions, 2010, pp. 263-269.
 T. E. Lipe, “Operation and Reference Manual for the NIST Automated AC-DC Calibration Systems and Software,” National Institute of Standards and Technology Special Publication 250-61, National Institute of Standards and Technology, 2004.
 H. A. Mageed, A. F. Zobaa, M. H. A. Raouf, A. H. A. Rahman and M. M. A. Aziz, “An Improved Design of a Fully Automated Multiple Output μPotentiometer,” Energy and Power Engineering Transactions, May 2010, pp. 103-110.