A method for measuring a contact resistance at an interface of an electrically conductive coating and a cross-ply surface of a composite layer having electrically conductive fibers. The method includes: placing a dielectric coating of a sensing pad in contact with the composite layer or with the electrically conductive coating on the cross-ply surface of the composite layer; electrically connecting first and second input terminals of a comparator to the sensing pad and to one side of a capacitor respectively; electrically connecting another side of the capacitor to a fixed resistance; electrically connecting the fixed resistance to an electrically conductive body inserted in a hole in the composite layer; supplying an alternating current to the electrically conductive body and to the fixed resistance; and outputting a characteristic voltage signal if an amplitude of the input signal at the first input terminal is at least equal to an amplitude of the input signal at the second input terminal.

A contact detection circuit is applied to a four-terminal measurement device. The contact detection circuit comprises a first isolator, a signal generator, a multiplier and a calculator. The first isolator comprises a primary side and a secondary side, with the secondary side comprising a first terminal and a second terminal, with the first terminal configured to be electrically connected to a driving terminal and the second terminal configured to be electrically connected to a measuring terminal. The signal generator is configured to provide a measuring signal. The multiplier is configured to generate an output signal based on the measuring signal and a first reflected signal when the first reflected signal is induced at the primary side of the first isolator based on the measuring signal. The calculator calculates contact resistance between the driving terminal and the measuring terminal based on a direct-current component of the output signal.

A display device including a display panel including a plurality of pixels connected to a plurality of data lines and a plurality of gate lines crossing the plurality of data lines; a data driver comprising a plurality of terminals in contact with a plurality of pads on the display panel through a conductive adhesive member and configured to detect a resistance value of the plurality of terminals; and a timing controller configured to transfer the resistance value to an external controller.

A ground electrode (100) positioned in the earth and a monitoring device (200) configured to measure a current and resistance of a ground line, where the monitoring device (200) includes a ground current sensing unit (210) configured to measure the current of the ground line, a resistance sensing unit (220) configured to measure ground resistance of the earth and an earth resistance rate, a voltage sensing unit (230) configured to check a voltage value of commercial power, a temperature and humidity sensing unit (240) configured to check a surrounding temperature and humidity of the monitoring device (200), and a monitoring unit (250) configured to confirm whether the ground current, ground resistance and earth resistance measured are abnormal values by compared with reference values classified based on the temperature and humidity measured.

A ground electrode (100) positioned in the earth and a monitoring device (200) configured to measure a current and resistance of a ground line, where the monitoring device (200) includes a ground current sensing unit (210) configured to measure the current of the ground line, a resistance sensing unit (220) configured to measure ground resistance of the earth and an earth resistance rate, a voltage sensing unit (230) configured to check a voltage value of commercial power, a temperature and humidity sensing unit (240) configured to check a surrounding temperature and humidity of the monitoring device (200), and a monitoring unit (250) configured to confirm whether the ground current, ground resistance and earth resistance measured are abnormal values by compared with reference values classified based on the temperature and humidity measured.

A device, including: a sensor circuit that senses the state of contact impedance of a mechanical electrical switch; and a switch-off circuit that represents a sensed high impedance contact of the switch as a low or constant impedance, where the sensor circuit detects an open or closed condition of the switch by sensing a voltage across the switch passing a threshold value.

An inspection tool and associated methods for testing physical and electrical properties of a perforating gun segment, wherein the perforating gun segment is received in a perforating gun segment holder positioned between a first connecting portion and second connecting portion. The inspection tool may be for establishing, testing, and confirming the position of an internal gun assembly and the electrical properties of certain electrical connections of the perforating gun segment. Electrical testing contacts and/or distance sensors may be positioned on one of the first connecting portion and the second connecting portion for measuring the position of the internal gun assembly and the electrical properties. In an aspect, the inspection tool may include a piston for pushing, via the first connecting portion, the internal gun assembly to a predetermined position, and establishing electrical connections to test the electrical properties of the perforating gun segment.

A method for nondestructive inspection of ceramic structures present as either a ceramic matrix composite structure or a ceramic based coating. Such non-metallic structures are used to provide thermal protection or weight reduction or both to aircraft and their components. The nonmetallic structure is scanned with an electromagnetic pulse in the range of 200 GHz to 4 THz. The electromagnetic pulse includes a plurality of frequencies within the Terahertz range and is not restricted to a single designated frequency. The frequency range is sensitive to changes in impedances and refractive index within the structure. After the electromagnetic pulse passes through the nonmetallic structure, it may be evaluated for changes in impedance in the nonmetallic structure at different locations, and, when present, whether the changes in impedance impact the ability of the structure to perform the function for which it was designed.

A method for nondestructive inspection of ceramic structures present as either a ceramic matrix composite structure or a ceramic based coating. Such non-metallic structures are used to provide thermal protection or weight reduction or both to aircraft and their components. The nonmetallic structure is scanned with an electromagnetic pulse in the range of 200 GHz to 4 THz. The electromagnetic pulse includes a plurality of frequencies within the Terahertz range and is not restricted to a single designated frequency. The frequency range is sensitive to changes in impedances and refractive index within the structure. After the electromagnetic pulse passes through the nonmetallic structure, it may be evaluated for changes in impedance in the nonmetallic structure at different locations, and, when present, whether the changes in impedance impact the ability of the structure to perform the function for which it was designed.

Embodiments disclosed herein are directed towards systems and methods for electric current leakage detection in a land seismic system. Embodiments may include generating at least one test signal using a digital to analog converter DAC circuitry, wherein the DAC circuitry includes an output operatively connected to earth ground. Embodiments may further include alternately grounding a positive path to an analog to digital converter ADC circuitry during a first time window and a negative path to the analog to digital converter during a second time window while measuring an ADC signal. Embodiments may also include determining an average amplitude of the first time window and the second time window and determining a leakage resistance based upon, at least in part, the average amplitude of the first time window and the second time window.