An instrument is presented for measuring major MOSFET parameters. It implements the method of charge pumping as well as providing static I-V characteristics. The former capability enables one to investigate the quality of semiconductor-insulator interfaces and to determine mean surface-state density. Employing a USB-compatible microcontroller, the instrument has a reasonable size (100 × 80 × 50 mm3), mass (300 g), and power consumption (at most 2.5 W). The instrument is controlled via a USB bus by a personal computer running specially designed software under Microsoft® Windows 2000/XP®. It can measure currents from 1 pA to 10 mA with the gate or drain voltage varied across the range ±10 V, the MOSFET under test being connected as a two-port. Mean surface-state densities down to 10 9 cm-2 eV-1 can be determined. © 2008 MAIK Nauka.