Precious metal testing apparatus with calibration system

A calibration system for a precious metal testing apparatus having an electronic circuit interconnecting a microprocessor, a test pad, an external probe, and a source of electrical power for testing the precious metal content of an object, said calibration system comprising:

• a calibration switch mounted on said testing apparatus to initiate a calibration procedure;
• a metering circuit interconnecting said test pad and said probe to detect a galvanic voltage generation within said test probe when a known quality test specimen is electrically coupled between said test pad and said probe to generate an initial reading indicative of said galvanic voltage;
• said microprocessor comparing said initial reading with a theoretical reading corresponding to said test specimen stored within look-up tables in said microprocessor, said initial reading being used to determine normalization of said probe which is attained when said microprocessor confirms that said initial reading is within predefined acceptable limits from said theoretical reading;
• and
• said microprocessor operating said calibration procedure after said probe has been normalized by calculating the difference between the initial reading and the theoretical reading and applying an algorithm corresponding to said theoretical reading from said look-up tables to said initial reading to generate a recalibrated response curve for different percentages of precious metal, said recalibrated response curve comprising a response curve using said probe having current operational parameters for said known test specimen from the look-up tables adjusted by the difference between said initial reading and said theoretical reading, all subsequent test readings of objects being tested being compared to said recalibrated response curve to determine the precious metal content of each subsequently tested object, said recalibrated response curve being used for all subsequent test readings until said calibration system is subsequently operated to create a new recalibrated response curve corresponding to a new said probe or changes in said operational parameters.

A calibration method of calibrating a precious metal testing apparatus having an electronic circuit interconnecting a microprocessor, a test pad, an external probe, and a source of electrical power for testing the precious metal content of an object, comprising the steps of:

• electrically coupling a known quality test specimen between the test pad and the probe to generate a galvanic voltage within said probe;
• detecting the galvanic voltage by a metering circuit within said electronic circuit and generating an initial test reading received by the microprocessor;
• comparing the initial test reading to a theoretical reading for the known quality test specimen stored in look-up tables within said microprocessor to determine normalization of said probe when said initial test reading is within a predetermined acceptable limit from said theoretical reading;
• after normalization of said probe, calculating a delta differential between the initial test reading and the corresponding theoretical reading;
• storing the delta differential in the microprocessor;
• and
• utilizing the delta differential to recalibrate any subsequent readings taken of objects to be tested for precious metal content by applying an algorithm corresponding to a graphical plotting of different percentages of precious metal content corresponding to the theoretical reading stored in said look-up tables to generate a recalibrated response curve for use during subsequent operations of said precious metal testing apparatus to compare all said subsequent readings taken of objects to be tested for precious metal content until said calibration method is subsequently operated, said recalibrated response curve comprising a response curve for said known test specimen from the look-up tables adjusted by the delta differential between said initial reading and said theoretical reading, changes in said probe including changes in operational parameters for said probe requiring the creation of a new recalibrated response curve.