A method is for monitoring a ground resistance of an electric installation which consists of an ungrounded stationary alternating-voltage power supply system having at least one active conductor and of a consumer connected to the stationary alternating-voltage power supply system via a supply line. For this method, the already available active conductors of the stationary alternating-voltage power supply system and the leakage capacity of the leakage capacitor installed in the consumer are used to complete a measuring-current circuit for monitoring the ground resistance, a measuring signal being capacitively coupled between the active conductor and ground via a coupling circuit. Measuring currents and measuring voltages are measured when the consumer is switched on and off, a complex-valued load-side impedance, which has the ground resistance to be monitored in its real part, being detected from these measurements.

In an example, monitoring circuitry includes a first and a second coupling to electrically connect the monitoring circuitry to a monitored circuit having a resistance. The resistance of the monitored circuit may be indicative of a status, and the monitored circuit may be connected in series between the first and second coupling. The first coupling comprises a plurality of galvanically separated connection elements which are to form an electrical connection with a common connection element of the monitored circuit. The monitoring circuitry further comprises a monitoring apparatus to determine the resistance of the monitored circuit via the first coupling and the second coupling. The monitoring apparatus is to acquire a plurality of electrical values and to use the plurality of electrical values to determine a value of the resistance of the monitored circuit.

In a method for the determination of an electrical contact property in a contact region between a first contact element of a first plug device and a second complementary contact element of a second plug device, a property of a current path including the first contact element, the contact region, and from the second plug device only the second contact element is evaluated and an induction voltage is generated in the current path for a measurement in the current path to thereby enable to draw a conclusion about the electrical contact property.

A method for measuring insulation resistance in an inverter that has a DC link circuit and a bridge circuit, connected to the DC link circuit, for driving an AC current via a bridge center tap is disclosed. The method includes connecting the bridge center tap to a grounding point, successively connecting, by way of the bridge circuit, the bridge center tap that is connected to the grounding point to two points of the ungrounded DC link circuit that differ in terms of voltage, and measuring the current flowing from the two points that differ in terms of voltage to the grounding point. The two points of the ungrounded DC link circuit that differ in terms of voltage are selected from a group of points that includes at least one intermediate voltage point of the DC link circuit in addition to two end points of the DC link circuit, such that the voltages present between the two points that differ in terms of voltage and the grounding point do not exceed a predefined voltage limit value.

A method is for monitoring a ground resistance of an electric installation which consists of an ungrounded stationary alternating-voltage power supply system having at least one active conductor and of a consumer connected to the stationary alternating-voltage power supply system via a supply line. For this method, the already available active conductors of the stationary alternating-voltage power supply system and the leakage capacity of the leakage capacitor installed in the consumer are used to complete a measuring-current circuit for monitoring the ground resistance, a measuring signal being capacitively coupled between the active conductor and ground via a coupling circuit. Measuring currents and measuring voltages are measured when the consumer is switched on and off, a complex-valued load-side impedance, which has the ground resistance to be monitored in its real part, being detected from these measurements.

A measurement module receives a defined system topology and system component characteristics information for a system. The measurement module calculates an expected system impedance for the defined system topology. The measurement module collects one or more impedance measurements using a high frequency voltage stimulus. Finally, the measurement module compares the one or more impedance measurements with the expected system impedance to determine adequacy of protective grounding of the system.

A method for obtaining a contact resistance of a planar device includes: obtaining a contact resistance of a planar device by using a potential measurement method, in the measurement of the surface potential distribution, the planar device is in a state of current flowing, a certain voltage drop is formed at a junction area of the device; extracting the voltage drop measured through the Kelvin microscope by using a linear fitting method; and dividing the measured voltage drop by the current flowing through the device, thereby accurately calculating the magnitude of the contact resistance at the junction area of the planar device. With the present invention, the contact resistance of the planar device can be precisely measured, which is suitable for the contact resistance measurement experiments of devices such as thin film transistors and diodes. The invention has the advantages of reasonable theory, accurate result, simple and easy operation, and is favorable for optimizing the device performance and establishing a complete electrical model of the device.

In an example, monitoring circuitry includes a first and a second coupling to electrically connect the monitoring circuitry to a monitored circuit having a resistance. The resistance of the monitored circuit may be indicative of a status, and the monitored circuit may be connected in series between the first and second coupling. The first coupling comprises a plurality of galvanically separated connection elements which are to form an electrical connection with a common connection element of the monitored circuit. The monitoring circuitry further comprises a monitoring apparatus to determine the resistance of the monitored circuit via the first coupling and the second coupling. The monitoring apparatus is to acquire a plurality of electrical values and to use the plurality of electrical values to determine a value of the resistance of the monitored circuit.

A semiconductor device includes an external terminal, a switching output stage that performs switching drive of a terminal voltage at the external terminal, an output control unit arranged to generate a drive signal for the switching output stage according to an input pulse signal, a counter arranged to count the number of pulses of the input pulse signal so as to generate a mask signal, a logical gate arranged to mask the input pulse signal according to the mask signal, and a comparator arranged to compare the terminal voltage with a predetermined threshold value voltage so as to generate a reset signal of the counter.

An inspection tool and associated methods for testing physical and electrical properties of a perforating gun and sending the perforating gun to a wellbore site with at least one of an electrical property and a dimension that has been previously verified. The perforating gun may be received in a perforating gun holder positioned between a first connecting portion and second connecting portion. The first connecting portion may be moved from a first position to a second position at which the at least one of the electrical property and the dimension is measured. Upon verification that the at least one of the electrical property and the dimension is within a predetermined specification, the perforating gun may be sent to the wellbore site.