A microcontroller-based current electrometer built from LOG112 and C8051F006 system-on-a-chip has been developed for measuring current flowing through a MOS (metal–oxide–semiconductor) device. The Fluke 5100B series calibrator and a computer have been used to calibrate the electrometer. In order to examine the performance of the electrometer, Al|SrTiO3|Si and BS250 MOSFET-based MOS devices have been employed as devices under test and the Keithley 617 Programmable Electrometer has been applied as a reference. It has been found that the currents measured by the Keithley 617 Programmable Electrometer were reproduced very well by the developed electrometer.

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A current loop receiver system based on a microcontroller has been developed. The current loop receiver system can serve 8 gas sensors with 4-20 mA outputs, which are handled by employing a multiplexer. The data acquisition of the system is composed of a common operational amplifier-based current loop receiver, a CD4051 multiplexer, an ADS7822 serial analog to digital converter (ADC), and an AT89S52 microcontroller. The measured gas concentration is displayed on the 7-segments or transmitted to a personal computer via the RS232 serial communication to be processed by the Microsoft Excel. Additional functions such as gas concentration level warning and error code display are also provi ded.

The hardware and software of the Keithley 617 Programmable Electrometer System, which is used for electrical characterization of materials and devices, have been automated so that users can work under convenient environment. The main constraint in automation of the system was budget. It was decided t hat the PCL488 ISA card is reused. The computer supporting the ISA bus was Pentium II with 128 Megabytes of RAM and the best operating system for the Pentium II computer was Windows 98 SE. The software driver for the PCL488 card was also updated to be CEC488 v7, which is the latest version for Windows. Interactive software for measurement, processing and displaying data has been written by using the Borland Delphi version 6.0, which is a programming language with graphical-user interface capability. Therefore, users can operate the system conveniently.