Portable hand-held voltage sensor with manually adjustable reference voltage for comparison with sensed voltage

Claim 1

A voltage sensor device comprising: a portable housing suitably sized for hand-held use; a first conductor means extending from one end of said housing for contacting a first voltage potential; a second conductor means extending from said housing for connection to a ground potential; means within said housing for providing a first adjustable reference D.C. voltage level; means connected to said first adjustable reference voltage providing means for providing a second reference D.C. voltage level that is continuously less than said first reference voltage level by a predetermined amount; thumbwheel means accessible on the outside of said portable housing for allowing manual adjustment of said first reference voltage level; means connected to said first adjustable reference voltage level providing means, said second reference voltage level providing means and said first conductor means to compare the first voltage potential with both said first reference voltage level, for providing a first D.C. output signal when said first voltage potential is less than said first reference voltage level, and said second reference voltage level, for providing a second D.C. output signal when said first voltage potential is greater than said second reference voltage level; and means for distinctively indicating the presence or absence of any of said output signals.