Technology includes a current sensor that detects electric current flowing through an object. The current sensor includes a magnetic core through which the object is inserted, a coil wound around the magnetic core, a transmission line that transmits electric current supplied from the coil, a terminating resistor that converts electric current from a terminating end of the transmission line into voltage and outputs the voltage, and an impedance matching unit that implements impedance matching between the coil and the terminating resistor. The impedance matching unit raises, to a characteristic impedance of the transmission line, at least one of an impedance viewed from the terminating end of the transmission line toward the terminating resistor and an impedance viewed from a starting end of the transmission line toward the coil, in a band of frequency components involving amplitude attenuation among frequency components of the voltage output from the terminating resistor.

A probe device has a main body and a probe body that can be rotatable relative to one another to change a shape of the probe device. This allows a user to use the probe device with the rotated probe body to reach behind areas that are difficult to reach into when the probe body is not rotated. The probe device could also have both a probe connector and an inductive clamp, where the probe connector could be used to measure a voltage of a conductive surface of an electronic circuit under test and the inductive clamp could be used to inductively measure a current flowing through a wire of an electronic circuit under test. The probe device is preferably configured with a grip configured to open and close the inductive clamp and a user interface positioned opposite the grip.

A probe for use with a measuring instrument. The probe is a wired probe assembly comprising a housing with an integrated user interface. The wired probe assembly further comprises a measuring component for contacting a device to be measured and a cord component connecting the measuring component to the measuring instrument. The user interface can indicate a status of an electrical parameter and allow an operator to provide inputs remotely to the measuring device.

Methods and systems are described for monitoring and compensating an offset between a reference voltage used in a first device and a corresponding reference voltage used in a second device. The first device can include offset circuitry. The offset circuitry receives two voltage signals. The first voltage signal is equal to a first voltage value that is used as a reference voltage in the first device. The second voltage signal can be a time-varying voltage signal that has a known relationship with a second voltage value that is used as a reference voltage in the second device. The offset circuitry can then determine the second voltage value from the second voltage signal, and output an offset value based on a difference between the first voltage value and the second voltage value.

Methods and systems are described for monitoring and compensating an offset between a reference voltage used in a first device and a corresponding reference voltage used in a second device. The first device can include offset circuitry. The offset circuitry receives two voltage signals. The first voltage signal is equal to a first voltage value that is used as a reference voltage in the first device. The second voltage signal can be a time-varying voltage signal that has a known relationship with a second voltage value that is used as a reference voltage in the second device. The offset circuitry can then determine the second voltage value from the second voltage signal, and output an offset value based on a difference between the first voltage value and the second voltage value.

The present invention aims to reduce the leakage current that flows when measuring a high voltage and includes: a voltage detector that detects a voltage and outputs a detection voltage; a current supplier that supplies a measurement current across a pair of input terminals via a protective resistor; and a processor that executes a voltage measurement process, which measures the voltage based on data indicating the detection voltage, and a resistance measurement process, which measures a resistance connected between the input terminals based on the voltage and the current. A first switch is connected in parallel to the protective resistor and the processor executes the voltage measurement process in a state where the first switch has been set open to measure the terminal voltage, and executes the resistance measurement process by setting the first switch shorted when the voltage is equal to or below the reference voltage value.

A current detection apparatus includes a voltage detector, a candidate voltage generator, a temperature detector and a correction voltage selector. The voltage detector includes an output terminal for outputting a detected voltage according to a load current. The candidate voltage generator includes correction resistors connected in series and connecting the output terminal and a ground. The candidate voltage generator generates candidate voltages at respective sections across the corresponding correction resistors. The temperature detector detects a temperature of a semiconductor switch. The correction voltage selector selects one of the candidate voltages as a corrected voltage. The one of the candidate voltages is weighted with corresponding one of the corrected magnification scales corresponding to an on-resistance of the semiconductor switch at the measured temperature. The corrected voltage indicates a corrected current value with correction of the load current according to the measured temperature.

A current detection apparatus includes a voltage detector, a candidate voltage generator, a temperature detector and a correction voltage selector. The voltage detector includes an output terminal for outputting a detected voltage according to a load current. The candidate voltage generator includes correction resistors connected in series and connecting the output terminal and a ground. The candidate voltage generator generates candidate voltages at respective sections across the corresponding correction resistors. The temperature detector detects a temperature of a semiconductor switch. The correction voltage selector selects one of the candidate voltages as a corrected voltage. The one of the candidate voltages is weighted with corresponding one of the corrected magnification scales corresponding to an on-resistance of the semiconductor switch at the measured temperature. The corrected voltage indicates a corrected current value with correction of the load current according to the measured temperature.

Systems and methods are provided for measuring electrical parameters in an insulated conductor without requiring a galvanic connection. A sensor probe is provided that includes a body and a flexible arm or strap that is movable between an open position that allows a conductor to be moved into and out of a measurement area of the probe, and a closed position that secures the insulated conductor within the measurement area so that one or more measurements may be obtained. The electrical parameter sensor probe may include a non-contact sensor coupled to at least one of the body or the flexible arm. A user may apply a force to an actuator (e.g., slide switch) which moves the flexible arm from the closed position into the open position against a bias force so that the insulated conductor under test may be positioned and secured in the measurement area of the sensor probe.

Systems and methods for measuring DC voltage of an insulated conductor (e.g., insulated wire) are provided, without requiring a galvanic connection between the conductor and a test electrode or probe. A non-contact DC voltage measurement device may include a conductive sensor that is mechanically oscillated. The device may also include a conductive internal ground guard that is galvanically isolated from the conductive sensor, and a conductive reference shield that is galvanically insulated from the internal ground guard. The device may further include a common mode reference voltage source that generates an alternating current (AC) reference voltage, and a sensor signal measurement subsystem electrically coupled to the conductive sensor. Control circuitry may receive a sensor current signal from the sensor signal measurement subsystem, and determine the DC voltage in the insulated conductor based at least in part on the received sensor current signal.