A direct current (DC) power rail probe includes a single-ended probe tip, and a two-path circuit having an input coupled to the single-ended probe tip and an output configured for connection to measurement equipment such as an oscilloscope. The two-path circuit includes an alternating current (AC) path in parallel with a feed-forward (FF) path, the AC path including a capacitive element, and the FF path including a series connection of at least one resistive element and an amplifier. The probe tip and two-path circuit are selectively operable in a non-attenuating mode and an attenuating mode.

A direct current (DC) power rail probe includes a single-ended probe tip, and a two-path circuit having an input coupled to the single-ended probe tip and an output configured for connection to measurement equipment such as an oscilloscope. The two-path circuit includes an alternating current (AC) path in parallel with a feed-forward (FF) path, the AC path including a capacitive element, and the FF path including a series connection of at least one resistive element and an amplifier. The probe tip and two-path circuit are selectively operable in a non-attenuating mode and an attenuating mode.

A current transformer (CT) for the purpose of, for example, current measurement, that uses a power line as a first coil and a second coil for measurement purposes, is further equipped with a third coil. Circuitry connected to the third coil is adapted to measure a signal therefrom. The measured signal from the third coil is compared to a signal measured from the second coil and based on the results, internal CT parameters are determined allowing calibration of actual results to expected results thereby providing an improved accuracy. This is especially desirable when using the CT for measurement of the like of current or phase of the primary coil when measurements are adjusted using the newly determined calibration parameters.

A current transformer (CT) for the purpose of, for example, current measurement, that uses a power line as a first coil and a second coil for measurement purposes, is further equipped with a third coil. Circuitry connected to the third coil is adapted to inject a known reference signal to the third coil of the CT. The injected reference signal, i.e., current, generates signals in the first and second coils of the CT. The signal generated in the second coil is compared using circuitry attached thereto to the reference signal. Based on the results, and the difference between the expected results and the actual results, updated calibration parameters are determined. These provide improved accuracy when using the CT, for example for measurement of the like of current or phase of the primary coil when measurements are adjusted using the newly determined calibration parameters.

A current transformer (CT) for the purpose of, for example, current measurement, that uses a power line as a first coil and a second coil for measurement purposes, is further equipped with a third coil. Circuitry connected to the third coil is adapted to inject a known reference signal to the third coil of the CT. The injected reference signal, i.e., current, generates signals in the first and second coils of the CT. The signal generated in the second coil is compared using circuitry attached thereto to the reference signal. Based on the results, and the difference between the expected results and the actual results, updated calibration parameters are determined. These provide improved accuracy when using the CT, for example for measurement of the like of current or phase of the primary coil when measurements are adjusted using the newly determined calibration parameters.

A method includes selecting a state model control, as an operational state of the heater, from among a plurality of state model controls, measuring an electrical characteristic of the heater, where the electrical characteristic includes at least one of an electric current and a voltage, and controlling power to the heater based on the selected operational state and based on the measured electrical characteristic.

The objective of the present invention is to provide a relay-welding detection device and method, the device and method capable of determining, whether a relay is welded, by using an analog-digital converter (ADC). Another relay-welding detection device according to the present invention comprises: a first ADC for measuring a voltage of a relay input terminal; a second ADC for measuring a voltage of a relay output terminal; and a CPU for comparing the voltage of the relay input terminal with the voltage of the relay output terminal and determining whether the relay is welded.

The objective of the present invention is to provide a relay-welding detection device and method, the device and method capable of determining, whether a relay is welded, by using an analog-digital converter (ADC). Another relay-welding detection device according to the present invention comprises: a first ADC for measuring a voltage of a relay input terminal; a second ADC for measuring a voltage of a relay output terminal; and a CPU for comparing the voltage of the relay input terminal with the voltage of the relay output terminal and determining whether the relay is welded.

A system for precise measurement of current takes current from a current input terminal, the system includes a controlling unit, a voltage generating unit, a voltage amplifying unit, and a processing unit. After sampling the current, the controlling unit outputs a control signal to the voltage generating unit. The voltage generating unit converts the current into different voltage signals. The voltage amplifying unit amplifies the voltage signal, and outputs the amplified signal to the processing unit. The processing unit converts the amplified voltage signal to obtain a corresponding value of current. The system accurately measures currents of different magnitudes, and improves the accuracy of current detection.

A system for precise measurement of current takes current from a current input terminal, the system includes a controlling unit, a voltage generating unit, a voltage amplifying unit, and a processing unit. After sampling the current, the controlling unit outputs a control signal to the voltage generating unit. The voltage generating unit converts the current into different voltage signals. The voltage amplifying unit amplifies the voltage signal, and outputs the amplified signal to the processing unit. The processing unit converts the amplified voltage signal to obtain a corresponding value of current. The system accurately measures currents of different magnitudes, and improves the accuracy of current detection.