Patent ID: 7135876

Claim:
An electrical feedback detection system for detecting electrical contact of a multi-point probe to a material test sample surface comprising: a. electric generator means connected to a first multitude of electrodes of a multi-point probe; b. a second multitude of switched impedance detection elements connecting said first multitude of electrodes of said multi-point probe; c. electrical detector means connected to the output of the voltage follower for detecting a measuring signal from the electrical signal across said second multitude of switched impedance detection elements, and d. an electrical connection between said electric generator means to said material test sample surface, in which the electric generator means is a differential voltage to current converter comprising: e. a precision amplifier providing two differential inputs, one output, and one reference input; f. a precision resistive element providing an internal and external port, said internal port connected to said output of said precision amplifier; and g. the voltage follower providing an input and an output, said input connected to said external port of said precision resistive element, and said output connected to said reference input of said precision amplifier.