Keithley Instruments Inc. has announced an addition to its Series 2400 SourceMeter instrument family. As with all of the company’s source measurement unit (SMU) instruments, Model 2401 is optimized for high-precision test applications such as current versus voltage characterization of photovoltaic cells, high-brightness LEDs, semiconductor devices, low-voltage materials and resistance measurements. It provides these advanced source and measurement unit capabilities at 20-V and 1-A signal levels. The stand-alone instrument integrates a stable DC power source with an instrument-grade 5 1/2- or 6 1/2-digit multimeter in a single enclosure. It can operate as a voltage and current source, a voltmeter, an ammeter and an ohmmeter, and it provides four-quadrant bipolar and automatic source/sink operation.