Silver testing apparatus

摘要

A precious metal testing apparatus determines the percentage content of precious metal in a specimen being tested by detecting the change in the rate of current flow through a resistive layer formed on the specimen by an application of a corrosive electrolyte on the specimen. The electrical circuit forms a fixed resistance circuit and a variable resistance circuit due to the formation of a growing resistive layer on the specimen such that the flow of current through the variable resistance circuit decreases as the flow of current through the fixed resistance circuit increase. The detection of the rate of change in current flow as a result of the increasing growth of the resistive layer can be compared to a look-up table that provides a corresponding percentage of precious metal in the specimen. Calibration of the testing apparatus can be accomplished with a specimen of known purity of the precious metal.

主权项

1. A method of determining the content percentage of silver within a specimen containing silver, comprising the steps of:
providing a testing apparatus having a microprocessor, a source of electrical current, and an electrical circuit including a pen probe having a supply of a corrosive electrolyte, said electrical circuit having a fixed resistance circuit path and a variable resistance circuit path; depositing said electrolyte from said pen probe onto said specimen to create a growing electrically resistive layer between the pen probe and the specimen, said electrically resistive layer having a rate of growth; measuring a flow of electrical current through at least one of said circuit paths as said electrically resistive layer accumulates; ascertaining a rate of change in said flow of electrical current through at least one of said circuit paths; and utilizing the rate of change in said flow of electrical current through said variable resistance circuit path to define the content percentage of silver within said specimen, the rate of growth of said electrically resistive layer being proportional to the content percentage of silver within said specimen, said growing electrically resistive layer decreasing the flow of electrical current through said variable resistance circuit path which contains said specimen.