The HP 4156A is a precision semiconductor parameter analyzer. Digital sweep parameter and a reliable tester, powerful failure analysis tool, and automated incoming inspection tool all in one package. 4 built in SMUs (2 VMUs, and 2 VSU s). The 4156A extends the current resolution to 1 fA and the accuracy of to 20 fA. It also utilizes full kelvin remote sensing on each SMU. All measurements are displayed on the color CRT screen and the ability to superimpose stored graphics from the graphics memory for comparison is available. Unit includes HPIB or serial output ports.