Abstract: A method is disclosed for reducing the common mode current flowing between the internal ground of an electrical circuit in an automotive vehicle, and the earth, when electric power is exchanged between an electric power storage unit of the electrical circuit and an electric power source external to the circuit. An electronic component is used to apply an electrical quantity as a function of the common mode current to an injection point in the circuit in order to reduce the common mode current. The value of the common mode current is obtained using a measuring device having a magnetic torus configured to be traversed by an electric line by which the electric power is exchanged, the electric line forming a primary winding, a secondary winding, wound about said torus for generating a magnetic flux on the basis of a reference current, and an oscillator for generating the reference current through the secondary winding.

Abstract: Embodiments related to magnetic current sensors, systems and methods. In an embodiment, a magnetic current sensor integrated in an integrated circuit (IC) and housed in an IC package comprises an IC die formed to present at least three magnetic sense elements on a first surface, a conductor, and at least one slot formed in the conductor, wherein a first end of the at least one slot and at least one of the magnetic sense elements are relatively positioned such that the at least one of the magnetic sense elements is configured to sense an increased magnetic field induced in the conductor proximate the first end of the at least one slot.

Abstract: Electrical current transducer comprising a measuring circuit (6) and an inductor (4) for measuring a primary current IP flowing in a primary conductor (2), the inductor comprising a saturable magnetic core (10) made of a highly permeable magnetic material and a secondary coil (12) for carrying an alternating excitation i configured to alternatingly saturate the magnetic core, the coil being connected to the measuring circuit. The measuring circuit is configured to measure a mean value of the excitation current in the secondary coil and determine therefrom a value of the primary current for small current amplitudes, the measuring circuit being further configured for evaluating the frequency of the excitation current i and determining therefrom the value of the primary current for large currents.

Abstract: A method for processing output from a current transformer comprising deriving signal data from the output; converting the signal data from analog to digital format; removing a carrier signal from the signal data; squaring the signal data; and performing a recursive RMS algorithm on the signal data.

Abstract: An arrangement for reducing a DC field component in the core of a transformer includes a compensation winding magnetically coupled to the core of the transformer, and a DC generator arranged in series with the compensation winding and with a reactance dipole. The reactance dipole is formed from a parallel circuit of an inductance and a capacitor to feed into the compensation winding a compensating current opposite in sense to the DC field component in the core. The inductance is formed from magnetically coupled first and second windings having N1 and N2 turns respectively, such that N2/N1<1. The first winding is connected on one end to the DC generator and on the other end to the compensation winding. The second winding is connected in parallel with the capacitor. The magnetic coupling of the first and second windings is established via a soft magnetic core having an air gap.

Abstract: A current measuring transducer for measuring the current flowing through an electrical cable, with a ring probe, a sensor and an evaluation device for recording the current value obtained by the ring probe and the sensor, wherein the ring probe has an annular core, wherein the ring probe is divided into a basic ring section and at least one movable ring section, wherein the movable ring section defines an open and a closed state, wherein in the open state, a radial cable insert opening is opened, and wherein a circularly closed arrangement is created in the closed state of the movable ring section in which the annular core surrounds the cable, wherein the radial insertion of a cable extending axially relative to the current measuring transducer into the inside area of the ring probe transfers the ring section from one to the other state, and measurement of the current in the cable inserted into the inside area is made possible in the closed state.

Abstract: An arrangement for use in an electricity meter includes a sensor and a processing circuit. The sensor is supported directly or indirectly by a meter housing. The sensor is configured to measure a magnetic field in proximity to a current sensor of the electricity meter. The sensor is also configured to generate a measurement signal representative of, at least in part, a magnitude of the magnetic field. The processing circuit is operably coupled to receive first information representative of the measurement signal. The processing circuit is configured to obtain a first value representative of the magnetic field based on the first information, and determine a first adjustment value responsive to a determination that the first value exceeds the first threshold value. The processing circuit is further configured to generate energy consumption information based at least in part on the first adjustment value.

Abstract: A current sensor is disclosed. The current sensor includes a Rogowski coil disposed on a flexible printed circuit board with at least one active lead passing through the Rogowski coil.

Abstract: What is disclosed is a current measuring apparatus comprising: a mains connector, such as a plug, for connecting to a wire of a mains supply; an apparatus connector, such as a socket, to provide for electrical conduction to an electrical apparatus; a coil in series between the mains connector and the apparatus connector; and a measurement circuit that is operative to measure a voltage drop across the coil. In particular the coil is one present to also filter the mains signal. Also disclosed is a mains voltage powered consumer product, a network and an adaptor utilizing the current measuring apparatus.

Abstract: Provided is a magnetic field detection device and a current sensor capable of increasing the degree of freedom in selecting the type of the magnetic field detection element. A magnetic field detection device 1 includes a conductor 3 that generates a magnetic field; a C core 2 provided so as to surround the conductor 3; and a magnetic field detection element 4 that detects a magnetic field. The C core 2 has a gap G1, and the magnetic field detection element 4 is disposed at a position where the magnetic field generated from the conductor 3 can be detected, the position being outside the gap G1. Since the direction of the magnetic flux varies outside of the gap G1 from place to place, the direction of the magnetic flux that passes through the magnetic field detection element 4 can be arbitrarily selected by arbitrarily selecting the installation location of the magnetic field detection element 4. Therefore, the degree of freedom in selecting the type of the magnetic field detection element 4 is increased.

Abstract: An electrical current sensor includes a first laminated body having a magnetic detection element disposed over a first substrate, a protective film formed over the first substrate and the magnetic detection element, and a coil formed over the protective film, and a second laminated body having a shield layer formed over a second substrate and which is formed by bonding the first laminated body and the second laminated body to each other with an adhesion layer interposed therebetween such that the magnetic detection element and the shield layer face each other.

Abstract: In a power line takeoff clamp assembly and method of use thereof an electrical power distribution line is clamped to a body of the clamp assembly. A power takeoff supported by the body clamped to the power line generates direct current from alternating current flowing in the power line. One or more sensors supported by the body clamped to the power line sense one or more values related to an electrical current flowing in a power line. A wireless transceiver supported by the body clamped to the power line communicates data regarding the one or more sensed values. Each sensor and the wireless transceiver utilize direct current generated by the power takeoff for the operation thereof.

Abstract: A device for monitoring and measuring the electrical and mechanical parameters of a power line conductor. Sensors of the device measure conductor temperature, the angle of inclination of the overhead conductor, current flowing in the conductor, and voltage to ground. The device has a low-power mode in which parameters of the power line conductor are not measured. Upon detecting a change in an electrical or mechanical value of the power line conductor, the device measures parameters of the power line conductor for a predetermined length of time before returning to the low power mode.

Abstract: In an electric current detector according to the present invention, an annular core 2 having a magnetic gap G and a Hall element 41 which is located in the magnetic gap of the core 2 and detects a magnitude of an electric current passing through the core 2 are arranged in an outer case 1. Here, in the core 2, a mold resin portion 3 which covers a surface of the core 2 over part of an overall length along a magnetic path thereof is molded at one or a plurality of portions along the magnetic path to configure an integral core component, the core component being fixed into the outer case 1 in a state where a surface of the mold resin portion 3 makes contact with an inner surface of the outer case 1.

Abstract: In a high voltage inverter device switching an input voltage to apply an exciting current to an excitation winding of a transformer and output an alternating-current high voltage from an output winding to supply the high voltage to a load from output lines, a point on the output line is connected to a frame ground. Each of a first and a second winding of the electrical leakage detecting transformer is interposed in series with the output line on a side where current flows out of the point and a side where current flows into the point respectively. A detection voltage Vd outputted from an amplifying winding is compared by a comparison voltage Vref, and an electrical leakage detection signal Sd is outputted when Vd>Vref. The first and second winding are opposite in winding direction to each other and equal in number of turns.

Abstract: A transfer switch selectively couples at least two power sources to a load. The load may be a home, business, or vehicle. A current transformer is coupled to the output of the transfer switch and generates a load measurement signal that is proportional to the current or power output from the transfer switch. A controller receives the load measurement signal and a switch setting describing the operation of the switch. The controller generates data for a status message for display based on the load measurement signal and the switch setting. The status message may describe the power consumption of the load or indicate when an error has occurred.

Abstract: A protective system far a power transformer having a neutral line connected to ground where large currents can flow in the neutral line due to electro-magnetic disturbances. The system includes circuitry for: (a) sensing the current level in the neutral line and whether it exceeds a predetermined threshold for a predetermined period; and (b) sensing and processing the harmonic content of the load current and determining the existence of certain relationships of the “even” and “odd” harmonics. Signals, including alarms, indicative of excessive conditions are produced. The system may also include circuitry for sensing the load current level and generating a signal alarm if the load level is above a given value when the harmonics and the DC current have values in excess of certain predetermined values.

Abstract: An apparatus for electrical current measurement. The apparatus may include a power input such as a current transformer that can be magnetically coupled to a line being measured. The apparatus may also include an energy harvesting circuit to parasitically harvest energy from the current transformer and an energy metering circuit to measure the current on the line. A controller can control the switching of a dynamic switch between an energy harvesting mode and an energy metering mode. The apparatus may also include a wireless transceiver. A plurality of these apparatuses may be combined into a network of devices to relay information from multiple current meters to a data concentrator and ultimately the Internet.

Abstract: According to one aspect, embodiments of the invention provide a current monitoring device comprising a current transformer configured to be removeably coupled to a power line and to generate a reference signal having a level related to a current level of the power line, a sensor circuit connected to the current transformer and configured to convert the reference signal to a measurement signal, a flexible cable having a first end and a second end, the first end coupled to the sensor circuit, and a connection portion coupled to the second end of the flexible cable and configured to be removeably coupled to a communications bus, wherein the sensor circuit is further configured to provide the measurement signal to the communication bus via the flexible cable and the connection portion.

Abstract: A system for sensing voltage in an isolated converter includes an input circuit isolated from an output circuit using a first transformer, the first transformer having a primary coil and a secondary coil, wherein the output circuit includes an output inductor and an output capacitor, and wherein the input circuit includes a power source that provides power to the output circuit through the first transformer; a feedback winding coupled to the output inductor to form a second transformer; and a monitor circuit that calculates a voltage across the output capacitor using a voltage across the feedback winding, a voltage across the primary coil of the first transformer, a turns ratio of the first transformer, and a turns ratio of the second transformer in order to provide feedback to control the input circuit.

Abstract: An induction heating system includes an induction heating coil operable to inductively heat a load with a magnetic field, a detector for detecting a current feedback signal corresponding to a current flowing through the induction heating coil, and a controller for detecting a switching transient in the current feedback signal and determining a resonant frequency of the system based on a characteristic of the switching transient.

Abstract: A flexible current and voltage sensor provides ease of installation of a current sensor, and optionally a voltage sensor in application such as AC branch circuit wire measurements, which may require installation in dense wiring conditions and/or in live panels where insulating gloves must be worn. The sensor includes at least one flexible ferromagnetic strip that is affixed to a current sensing device at a first end. The second end is secured to the other side of the current sensing device or to another flexible ferromagnetic strip extending from the other side of the current sensing device to form a loop providing a closed pathway for magnetic flux. A voltage sensor may be provided by metal foil affixed to the inside of the flexible ferromagnetic strip. A clamp body, which can be a spring loaded handle operated clamp or a locking fastener, can secure the ferromagnetic strip around the wire.

Abstract: The present invention concerns current transducers for measuring a current flowing through a cable. The current transducers have a ferromagnetic core providing a substantially ring-shaped portion and at least two legs. The ring-shaped portion has one air gap or two air gaps. A magnetic field sensor is placed in or at each of the air gap(s). The ring-shaped portion forms a magnetic circuit that encloses the cable and guides the magnetic field generated by current to the air gap(s). Each leg extends from the center of the associated magnetic field sensor in a direction that runs perpendicularly to the longitudinal axis of the cable and has a certain length. The length of the legs is designed so long that at least two magnetic paths are formed which guide a component of an external magnetic field which extends in the direction of the legs around the magnetic field sensor(s).

Abstract: A current detection circuit and a transformer current measurement system are offered, in which when elements and circuit, which cannot operate originally unless a transformer with small excitation inductance is used, are connected to a primary side of the transformer, even if the transformer, whose excitation inductance is large, is used, transformer current (primary current and secondary current) can be measured without deteriorating operations of the elements and circuit. [Means for solving] A current detector CT (current transformer) is in series connected to a primary winding 111 of a transformer 11, and an inductor La is in parallel connected to to a series connection of the current detector CT and the primary winding 111. And, secondary current I2 of the transformer 11 is measured based on a value of primary current IT detected by the current detector CT.

Abstract: A circuit includes a power circuit and a current sensing circuit. The power circuit has a main current loop. The current sensing circuit is spaced apart from and electrically decoupled from the power circuit. The current sensing circuit is operable to generate a voltage proportional to an electromagnetic field generated responsive to a current change in the main current loop of the power circuit and generate a current information signal based on the voltage. The current information signal describes the current in the main current loop.

Abstract: A current sensor includes a core arranged around a conductor, a sensing element arranged on the core and configured to generate an output variable dependent on a magnetic field in the core, and a measuring unit configured to detect the output variable and to derive a measured value of the current. The current sensor further includes a test coil arranged around the core and a test current generator connected to the test coil. The test current generator is configured to generate a test current signal of a specified amplitude and to output the test current signal to the test coil. The current sensor further includes a testing unit connected to both the measuring unit and the test current generator and configured to output information regarding the current sensor. The information is output as a test signal dependent upon comparing a first and a second measured value.

Abstract: A circuit for detecting a DC current in a conductor (L1) includes a current transformer (CT) having a ferromagnetic core (10), a primary winding comprising the conductor (L1) and at least one secondary winding (W1). The circuit further includes an oscillator (12) for supplying an oscillating signal across the secondary winding and means for detecting a dc offset in the current flowing in the oscillator circuit. The circuit includes a capacitor (C1) in series with the secondary winding, and the detecting means is arranged to detect a non-zero voltage across the capacitor above a certain level.

Abstract: An RF current probe is encapsulated in a conductive housing to permit its placement inside a plasma reactor chamber. An RF voltage probe is adapted to have a long coaxial cable to permit a measuring device to be connected remotely from the probe without distorting the voltage measurement.

Abstract: Embodiments relate to magnetic current sensors. In various embodiments, a current sensor can include a simple conductor having a constant cross-sectional profile, such as round, square or rectangular, and being generally free of any notches or slots to divert current and thereby having a simpler manufacturing process, lower resistance and improved mechanical robustness. In embodiments, the conductor can be formed of a non-magnetic conductive material, such as aluminum or copper.

Abstract: A current detection busbar has a penetrating portion that penetrates a hole portion of a magnetic core and two flat plate-like terminal portions that are respectively continuous with opposite sides of the penetrating portion. The terminal portions have a larger width and a smaller thickness than the penetrating portion. An insulating casing has busbar holes that are penetrated by the respective terminal portions of the current detection busbar. An edge portion of each busbar hole is constituted by flat surfaces that face the terminal portion with a gap left between each flat surface and the terminal portion, a plurality of projecting portions that sandwich the terminal portion while coming into contact with the front and back surfaces of the terminal portion, and curved surfaces that face respective corner portions of the terminal portion with a gap left between each curved surface and the corresponding corner portion.

Abstract: A magnetic sensor includes two sensor units with curved cores including meshing portions at front and base ends thereof and constructs a ring when the meshing portions mesh together. The meshing portions include main meshing portions that entirely overlap in a completely meshed state where the meshing portions overlap to the greatest extent. Auxiliary meshing portions that protrude inside and/or outside the ring are provided on the main meshing portions at the front and/or the base ends. In the completely meshed state, the auxiliary meshing portions do not overlap the main meshing portions or auxiliary meshing portions of the other core. In a non-completely meshed state where the main meshing portions partially do not overlap, the auxiliary meshing portions at least partially overlap the main meshing portions and/or auxiliary meshing portions of the other core.

Abstract: In a current detecting apparatus, a container member which constitutes a insulating housing includes an element supporting portion, a connector supporting portion, and a substrate fixing portion. The element supporting portion is formed with a depression to which a magnetism detecting portion of a Hall element is fitted. The connector supporting portion achieves positioning of a body portion of the connector by a fitting structure in three-dimensional directions where a lead terminal of a connector extends in parallel with lead terminals of the Hall element. The substrate fixing portion is a portion where a circuit board is fixed at one point. The body portion of the connector is also fixed to the circuit board with a screw.

Abstract: A current sensor comprising a primary conductor for conducting a current that is to be measured, at least two magnetic field probes for measuring magnetic fields, and a magnetic core, which has a closed ring structure having three or more corners that encloses the primary conductor, wherein each magnetic field probe is arranged on the magnetic core or in recesses in the magnetic core.

Abstract: A temperature compensated current measurement device comprises a Rogowski coil having a terminating impedance arranged to adjust the attenuation of the coil to balance changes in coil sensitivity so that the output voltage indicative of measured current remains substantially unchanged, the terminating impedance having different values above and below a threshold frequency.

Abstract: A device for measuring an electric quantity such as electric current flowing in an electric equipment unit, which device is in a case fitted on a mounting support, and having pass-through holes and terminals separated by insulating material, their number corresponding to the number of phases of the equipment unit, the holesto permit a conductor to pass therethrough, to be electrically connected to strips of terminals of the equipment unit the opposite end to electric contact strips of a load-side or line-side apparatus from the equipment unit and, for at least one terminal of the device, a magnetic core at least partially surrounding such terminal with an air-gap around which a secondary measuring coil is wound between two end portions of the magnetic core which define the air-gap, the coil(s) delivering a signal representative of the current flowing in the apparatus.

Abstract: A current sensing device and method of manufacturing a sensing device are disclosed. The current sensing device can include at least two current sensors, implemented in an openable ring-shaped support, and wherein the at least two current sensors can be arranged in a chain-like arrangement on the ring-shaped support, and wherein the at least two current sensors are electrically connected in series.

Abstract: A current clamp meter includes a current meter body and a jaw assembly. The jaw assembly is configured so that the current clamp meter may be used to reach and readily single-out a desired wire from amongst adjacent wires.

Abstract: The present invention relates to electromechanical device status monitoring and equipment protection applications for industrial automation, HVAC, and other implementations; and, more particularly, to the use of current sensing devices to detect loss-of-flow conditions. Presently described embodiments can comprise simplified, compact current sensing devices that can be economical to build, inventory, distribute, and purchase. Present embodiments can easily be calibrated and/or set by hand prior to installation, and they can be configured for automatically offering proof-of-flow detection based, at least in part, on the initially provided setting.

Abstract: A current sensor for measuring a current supplied to a conductor includes a case which accommodates an electrical parts therein, and a cover attached to the case. A groove part is provided on an outer surface of at least one of the case and the cover to allow the conductor to pass through the groove part. When the cover is attached to the case, the conductor arranged on the groove part is sandwiched between the case and the cover. A width of the groove part becomes narrower toward an interior side thereof.

Abstract: A current detection device includes a bus bar for current detection. The bus bar for current detection is constituted by a conductor provided with a first portion penetrating through a hollow portion of a magnetic material core in a first direction in which a current passes and plate-shaped second portions each linked to both sides in the first direction with respect to the first portion, the bus bar for current detection formed such that a width of the second portion is greater than a maximum width of the hollow portion of the magnetic material core and a minimum width of a contour of a section in the first portion is greater than a thickness of the second portion.

Abstract: The invention relates to a method and a device for determining a direct current (i(t)) flowing in a conductor (7) and having an amplitude greater than 500 A, which direct current (i(t)) is composed of a number of time-dependent partial currents (ii(t)) flowing in individual conductors (8) with switching elements. To create a drift-free measured value, it is provided that at least one Rogowski coil (10) is arranged around at least one of the individual conductors (8) for the induction of a partial voltage (ui(t)) through the at least one partial current (ii(t)), wherein the individual conductor (8) is formed by a path of a rectifier (6) on a secondary side of a transformer (5) with central tapping, the at least one integrator (11) is designed for integration of the at least one partial voltage (ui(t)), and the at least one integrator (11) is connected to an evaluation unit (12) for determining the direct current (i(t)).

Abstract: An integrated current sensing apparatus includes a magnetic-field sensing element, a power supply circuit, an offset adjustment circuit, a gain adjustment circuit and a regulating unit. The magnetic-field sensing element is configured for sensing magnetic field, and correspondingly generating a sensing voltage. The power supply circuit is electrically coupled to the magnetic-field sensing element, for generating a constant current to the magnetic-field sensing element to control the sensing voltage. The offset adjustment circuit is electrically coupled to the magnetic-field sensing element, for adjusting an offset of the sensing voltage. The gain adjustment circuit is electrically coupled to the offset adjustment circuit, for amplifying the sensing voltage to a rated output voltage. The regulating unit is electrically coupled to the power supply circuit, the offset adjustment circuit and the gain adjustment circuit, for controlling the constant current, the offset and a gain value.

Abstract: A current sensor packaged in an integrated circuit package to include a magnetic field sensing circuit, a current conductor and an insulator that meets the safety isolation requirements for reinforced insulation under the UL 60950-1 Standard is presented. The insulator is provided as an insulation structure having at least two layers of thin sheet material. The insulation structure is dimensioned so that plastic material forming a molded plastic body of the package provides a reinforced insulation. According to one embodiment, the insulation structure has two layers of insulating tape. Each insulating tape layer includes a polyimide film and adhesive. The insulation structure and the molded plastic body can be constructed to achieve at least a 500 VRMS working voltage rating.

Abstract: A device for sensing electrical current or voltage in an electrical distribution system using an actively compensated current ratio transformer that includes a first magnetic core having a first permeability and a second magnetic core having a second permeability higher than the first permeability. A primary winding having P turns is coupled with the first and second magnetic cores, a measurement winding having M turns is coupled with the first and second magnetic cores so that current in the primary winding induces current in the measurement winding, and a sense winding having S turns is coupled with the second magnetic core. An amplifier coupled to the sense winding receives a voltage developed across the sense winding and produces a compensation current in response to the received voltage. The amplifier has an output coupled to the sense winding to feed the compensation current through the sense winding to reduce the voltage developed across the sense winding voltage to substantially zero.

Abstract: An apparatus is provided for securing to and collecting power from an electrical conductor, including a current transformer comprising a core and an electrical winding that receives an induced current from magnetic flux generated according to alternating current present on the electrical conductor, and a clamping mechanism that attaches the apparatus to the electrical conductor. According to various aspects, apparatus may include a housing that encloses circuitry for monitoring conditions of the electrical conductor, where the circuitry includes one or more sensors, and wireless communications circuitry.

Abstract: A sensor includes a non-magnetic core having a first winding wrapped thereon. The first winding has a center tap dividing the first winding into a first winding portion and a second winding portion. The center tap is coupled to a reference voltage. The first winding portion and the second winding portion are configured to sense first AC signals, and have a balanced susceptibility to second AC signals. The differential integrating circuit is configured to provide common mode rejection of the second AC signals. The differential integrator circuit is operably coupled to the first winding portion and the second winding portion.

Abstract: A sensor includes a core, first and second windings, an integrating amplifier circuit and a DC balancing circuit. The first and second windings are wrapped around the core. The integrating amplifier circuit has a first input coupled to the first winding, and an output operably coupled to the second winding. The DC balancing circuit is operably coupled between the output of the integrating amplifier circuit and the first input of the integrating amplifier circuit.

Abstract: A current sensor includes: a magneto electric conversion element; and a magnetic field concentrating core applying a magnetic field caused by a measurement object current to the magneto electric conversion element. A planar shape of the magnetic field concentrating core perpendicular to a current flowing direction is a ring shape with a gap. The magneto electric conversion element is arranged in the gap. A part of a conductor for flowing the current is surrounded by the magnetic field concentrating core. The magnetic field concentrating core includes two first magnetic members and at least one second magnetic member, which are stacked alternately in the current flowing direction. Parts of the two first magnetic members adjacent to each other via the one second magnetic member are opposed to each other through a clearance or an insulator.

Abstract: A clamp meter has a main body and a stationary jaw fixed to an end of the main body. A hook portion of the clamp meter includes a movable jaw, a displacing means and a knob. The movable jaw is mounted on the main body corresponding to the position of the stationary jaw. The movable jaw and the stationary jaw together form a closed loop. The displacing means is mounted in the main body and comprises a displaceable rod connected to the movable jaw and a gear set for driving the displaceable rod. The knob is connected to the gear set for driving the displaceable rod and the movable jaw for linear displacement. The movable jaw is activated by the displaceable rod to generate a linear displacement, so that the user can operate the clamp meter more easily for measurement.

Abstract: A current sensor for measuring current through a conductor with the current sensor including a cable looped around the conductor to be monitored, and a transformer winding disposed in the cable for measuring current flow based on the Rogowski principle. The cable has opposite end portions coupled in an abutting relationship to form an endless loop with the winding flush with opposite end faces of the opposite and portions of the cable. The current sensor also has a coupling in the form of a sleeve including an assembly for attaching and detaching the opposite end positions of the cable having a stop ring which grips one of the end portions and a push button which is selectively movable against the stop ring for releasing the grip to open the opposite end portions. The cable may have a temperature sensor and a memory in which the measurement characteristics of the sensor are held. The sensor is reliable and accurate, and it can be left permanently in an electrical apparatus, or replaced, with no difficulty.