Construction and characterization of an automated contact resistance probe.

This memorandum describes the design, construction and calibration of a computer controlled probe for measuring the contact resistance of test coupons. A three axis precision positioning table driven by DC serve motors provides all the mechanical movements necessary for probing the sample and cleaning the probe tip. A data acquisition system controlled by a personal computer makes the electrical measurements required to compute contact resistance. The computer provides instructions to the positioning table, instructs the data acquisition system to make electrical measurements, calculates resistance and stores the results. Fixed weights provide the normal force on the contact; measured reproducibility is better than 1 gram in the 50 to 100 gram load range.