A Source Measurement Unit (SMU) is a flexible test instrument which is capable of both sourcing and measuring voltage and/or current at the same time. A SMU is made up of a constant current source, a constant voltage source, a voltmeter, and an ammeter. It allows seven modes of operation: voltage generation/current measurement (VS/IM), voltage generation/voltage measurement (VS/VM), current generation/voltage measurement (IS/VM), current generation/current measurement (IS/IM), and voltage generation (VS), current generation (IS), and resistance measurement (VS/IM or IS/VM).

SMUs are commonly used for characterization of semiconductor devices, electronic components and devices. Yokogawa offers single, dual, and low voltage/current SMUs to accommodate a wide variety of applications, and feature the fastest testing speeds in the industry.