Abstract: A system for testing integrated circuits is disclosed which uses a mechanical microprobe and the integrated circuit's CAD database. The system is integrated with the CAD database in such a manner that after an initial alignment operation between the CAD database and the integrated circuit being tested, the microprobe can be moved automatically to any spot on the circuit by choosing a point in the CAD database and placing a cursor on that spot. The microprobe is then automatically moved to the point so indicated. A contact sensing circuit allows the probe to be driven into the actual circuit to take measurements or inject test signals without fear of damaging the integrated circuit. The system can operate in numerous modes, each of which provide a different way of visualizing the circuit being tested.