The Keithley 2401 20V/1A/20W SourceMeter SMU Instrument is designed specifically for test applications that demand tightly coupled sourcing and measurement. The 2401 provides precision voltage and current sourcing as well as measurement capabilities; it is both a highly stable DC power source and a true instrument-grade 6 1/2-digit multimeter. The power source characteristics include low noise, precision, and readback. The multimeter capabilities include high repeatability and low noise. The result is a compact, single-channel, DC parametric tester. In operation, this instrument can act as a voltage source, a current source, a voltage meter, a current meter, and an ohmmeter. Manufacturers of components and modules for the communications, semiconductor, computer, automotive, and medical industries will find the 2401 invaluable for a wide range of characterization and production test applications.