A voltage detecting apparatus detects a detection voltage generated in a detected object which is covered by an insulator. The voltage detecting apparatus includes: a detection electrode that is disposed so as to contact the insulator directly, or indirectly via another insulator; a vibrator that causes the insulator to vibrate; a current-to-voltage converter circuit that converts a detection current to a detection voltage signal, the detection current flowing from the detected object via the detection electrode to a reference voltage in a state where the insulator is being caused to vibrate, having an amplitude that is modulated in accordance with a potential difference between the detection voltage and the reference voltage, and being synchronized with vibration of the vibrator; and a detector circuit that detects a detection output indicating the potential difference from the detection voltage signal.

Systems and methods provide a portable, verified voltage source that allows safe testing of separate non-contact voltage measurement systems. A proving unit of the present disclosure provides a known or specified alternating current (AC) voltage output across an insulated wire, which AC voltage may be fixed or may be user-selectable through a suitable user interface. The proving unit may include a visual indicator and/or an audible indicator that provides the user with an indication confirming that the proving unit is supplying an output voltage with the specifications of the proving unit, so the user will know that the proving unit is operating normally and is ready for testing a non-contact voltage measurement system. If the proving unit cannot provide the specified voltage output, the indicator(s) provides a signal to the user that the proving unit is currently non-functional.

Systems and methods provide a portable, verified voltage source that allows safe testing of separate non-contact voltage measurement systems. A proving unit of the present disclosure provides a known or specified alternating current (AC) voltage output across an insulated wire, which AC voltage may be fixed or may be user-selectable through a suitable user interface. The proving unit may include a visual indicator and/or an audible indicator that provides the user with an indication confirming that the proving unit is supplying an output voltage with the specifications of the proving unit, so the user will know that the proving unit is operating normally and is ready for testing a non-contact voltage measurement system. If the proving unit cannot provide the specified voltage output, the indicator(s) provides a signal to the user that the proving unit is currently non-functional.

Systems and methods provide a portable, verified voltage source that allows safe testing of separate non-contact voltage measurement systems. A proving unit of the present disclosure provides a known or specified alternating current (AC) voltage output across an insulated wire, which AC voltage may be fixed or may be user-selectable through a suitable user interface. The proving unit may include a visual indicator and/or an audible indicator that provides the user with an indication confirming that the proving unit is supplying an output voltage with the specifications of the proving unit, so the user will know that the proving unit is operating normally and is ready for testing a non-contact voltage measurement system. If the proving unit cannot provide the specified voltage output, the indicator(s) provides a signal to the user that the proving unit is currently non-functional. The proving unit may additionally verify contact voltage measurement systems (e.g., DMMs).

A current detecting apparatus measures an input current or an output current of an electronic apparatus. The current detecting apparatus includes a current detecting module, a direct-current measurement module and a current detecting module. The current detecting module includes a coil configured to electromagnetically couple to a path of an input or a path of an output of the electronic apparatus to obtain a first voltage signal. The direct-current measurement module measures the path of the input or the path of the output to obtain a second voltage signal. The current detecting module converts the first voltage signal into a first current command, and converts the second voltage signal into a second current command. The first current command is an alternating-current component of the input current or the output current. The second current command is a direct-current component of the input current or the output current.

A current detecting apparatus measures an input current or an output current of an electronic apparatus. The current detecting apparatus includes a current detecting module, a direct-current measurement module and a current detecting module. The current detecting module includes a coil configured to electromagnetically couple to a path of an input or a path of an output of the electronic apparatus to obtain a first voltage signal. The direct-current measurement module measures the path of the input or the path of the output to obtain a second voltage signal. The current detecting module converts the first voltage signal into a first current command, and converts the second voltage signal into a second current command. The first current command is an alternating-current component of the input current or the output current. The second current command is a direct-current component of the input current or the output current.

A current detection circuit includes: a resistor in a current path; first and second signal transmission units that transmit signals of first and second terminal sides of the resistor; a first difference operation unit that executes a difference operation on the signals transmitted by the first and second signal transmission units; a noise-capturing transmission unit starting point; third and fourth signal transmission units connected with the noise-capturing transmission unit starting point; a second difference operation unit that executes a difference operation on the signals transmitted by the third and fourth signal transmission units; and a summing operation unit that executes a summing operation on the first and second difference signals, wherein the first signal transmission unit and the fourth signal transmission unit are disposed close to each other and the second signal transmission unit and the third signal transmission unit are disposed close to each other.

A current detection circuit includes: a resistor in a current path; first and second signal transmission units that transmit signals of first and second terminal sides of the resistor; a first difference operation unit that executes a difference operation on the signals transmitted by the first and second signal transmission units; a noise-capturing transmission unit starting point; third and fourth signal transmission units connected with the noise-capturing transmission unit starting point; a second difference operation unit that executes a difference operation on the signals transmitted by the third and fourth signal transmission units; and a summing operation unit that executes a summing operation on the first and second difference signals, wherein the first signal transmission unit and the fourth signal transmission unit are disposed close to each other and the second signal transmission unit and the third signal transmission unit are disposed close to each other.

An electronic open-circuit current measuring circuit is configured to measure a current delivered between a current source and a load during an open circuit condition. The electronic open-circuit current measuring circuit includes an electronic voltage drop component electrically connected between a first buffer output and an electrical voltage difference calculating circuit. The voltage drop component is configured to reduce a first voltage level of the first buffered output voltage below a second voltage level of the second buffered output voltage in response to an open circuit condition.

A method and a control system for a multiphase-phase inverter system, the control system comprising an electric current detection circuit and a processor, wherein each phase of an electrical cycle is separated into a plurality of sections, inputs from the electric current detection circuit are received, each input indicating a measured phase current, and a phase current is calculated in each section, wherein the phase current calculation in at least one of the sections is determined from a changing ratio of the value of the phase current calculated from the measured values of the other phase currents in the multiphase system and the measured value of the phase.