Other

Etcon Corporation

Joseph A Rocci, Jr

David W Kirby

Kent L Earle

John Crosetto

An apparatus for determining the length of wires includes connector assemblies, a current source circuit, a voltage gain circuit, analog-to-digital converter, a read-only memory, a microprocessor and a display unit. The connector assemblies are connected across the ends of the wire whose length is to be determined. The current source circuit is used to selectively supply different values of currents to the wire whose length is to be determined. The voltage gain circuit is responsive to the different values of currents for selectively generating a plurality of different voltage levels for each of the different values of currents so as to provide an analog voltage signal having a predetermined range. The analog-to-digital converter is responsive to the analog voltage signal for converting the same to a first digital signal corresponding to a resistance of the wire. The read-only memory is used to store data representative of resistance per unit length of various sizes of wires having a uniform cross-sectional area and for storing programmed instructions. The microprocessor utilizes the first digital signal corresponding to the resistance of the wire and the stored data representative of resistance per unit area for generating a second digital signal representative of the length of the wire. The display unit is responsive to the second digital signal for indicating the wire length.

Wire length meter suppling current to a wire from which a signal

Portable apparatus for testing the quality of a ground connection between the ground prong of a tool plug and the tool housing, and for testing the quality of insulation between the tool plug power prongs and the tool housing. The apparatus comprises an enclosure having a plug at one end adapted to be received into a conventional utility wall outlet and a receptacle at the other end for receiving a tool power plug. A pair of electrical contact plates are provided as two adjacent outside walls of the enclosure. Threshold detection circuitry carried internally of the housing is connected to the power and ground receptacles of the apparatus plug and to the contact plates. A first portion of the circuitry is effective for measuring the resistance between the ground prong of a tool plug inserted into the apparatus receptacle and a tool housing in physical contact with one of the contact plates. A second portion of the circuitry is effective for simultaneously measuring the resistance between the tool plug power prongs and the tool housing. LED's are connected to the measuring circuitry and observable by a user for indicating safe or unsafe ground or insulation quality.

Apparatus for testing the quality of the ground connection and the

A device for testing electrical continuity at an industrial or household grounded A/C power outlet which is connected to an A/C line voltage through a ground fault circuit breaker. The device includes a housing having at one end thereof an A/C hot, an A/C neutral and a ground prong, and at the other end three lamps electrically connected between corresponding pairs of prongs to provide an indication of the presence or absence of an A/C voltage between the prong pairs when the prongs are received in plug-in connection into the outlet to be tested. The device further includes a momentary switch electrically connected between the A/C hot prong and the ground prong, and which, when activated, provides an overload current leakage path from the A/C line to ground so that the device may be used to check both the electrical continuity at the outlet and the operability of the ground fault circuit breaker in a single step.

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Palos Heights, IL, United States of America

Joseph A Rocci, Jr