Patent ID: 6150945
Filing Date: 2000-11-21
Classification: G01R

Abstract:
A pre-discharge monitor for sensing the intensity of a changing electric field, extending from a source of static electrical charge, and alerting a user when said electrical field exceeds a preset limit, said pre-discharge monitor comprising:a first conductive element in close proximity, without direct contact, to said source of static electrical charge;a second conductive element, spatially fixed at a location further from said source of static electrical charge than said first conductive element;a high impedance differential amplifier, interposed between said first conductive element and said second conductive element to provide a voltage signal proportional to said potential difference existing between said first conductive element and said second conductive element;a voltage level discriminator for receiving said voltage signal from said high impedance differential amplifier, said voltage level discriminator adapted to provide an alerting signal if said voltage signal exceeds a predetermined limit;an alerting circuit for receiving said alerting signal, said alerting circuit adapted to activate an alarm mechanism in the presence of said alerting signal to indicate that the electrical field has exceeded the preset limit; andwherein said device responds to voltage changes which occur over the range of 10 to 250 milliseconds.