Researchers and manufacturing managers, especially those involved in semiconductor and other component testing, are continually looking for ways to increase throughput and measurement integrity. This has led to an acute need for an instrument architecture that allows easy, low-cost customization and expandability without a cumbersome mainframe. Some new SMU instruments engineered for just this purpose extend source-measure resolution down to the one femtoamp level, which testing many semiconductor, optoelectronic, and nanotechnology devices often requires. This allows making accurate high speed measurements of leakage and quiescent currents, plus other critical low level applications.