A system and method for calibrating a capacitor voltage sensor that measures voltage on a power line coupled through a switch to a primary coil of a transformer. The method includes measuring a control voltage on a secondary coil of the transformer and measuring voltage on the capacitor sensor when the switch is known to be closed. The method identifies a calibration factor that when multiplied by the measured voltage on the capacitor sensor when the switch is closed makes the measured voltage on the capacitor sensor substantially equal to the control voltage. The method subsequently measures voltage on the capacitor sensor when the switch is open or closed during operation of the transformer, and multiplies the subsequently measured voltage on the capacitor sensor when the switch is open or closed by the calibration factor to obtain a measured voltage.

A measuring device facilitates equipment calibration. A measuring device for measuring noise contained in equipment having a prescribed resistance value is provided with a first voltage-dividing circuit connected to a direct-current power source, a second voltage-dividing circuit connected in parallel with the first voltage-dividing circuit , and a measuring unit which measures a first voltage-divided voltage output from the first voltage-dividing circuit, and a second voltage-divided voltage output from the second voltage-dividing circuit, a calculating unit which calculates the difference between the measured first voltage-divided voltage and second voltage-divided voltage, and an output unit which outputs the calculated result, wherein: the first voltage-dividing circuit outputs the first voltage-divided voltage from the equipment and a first resistor, connected in series.

An electronic device is provided. The electronic device includes an electronic unit, a sensing circuit and a circuit. The sensing circuit is electrically connected to the electronic unit through a sensing node. The circuit is electrically connected to the sensing node. The circuit is configured to apply a voltage to the sensing node.

A measurement system includes a gain chain configured to amplify an analog input signal; a range selector configured to select a gain between the analog input signal and a plurality of analog-to-digital converter (ADC) outputs from a plurality of ADCs, wherein each ADC output has a path, and a gain of each output path is made up of a plurality of gain stages in the gain chain; and a mixer configured to combine the plurality of ADC outputs into a single mixed output.

A apparatus, method, system and medium are provided. The apparatus includes: a buffer chain, including N first buffers connected end to end, N first AND gates with one input connected to a pulse signal and the other input connected to an output of a corresponding first buffer, and N flip-flops coupled with outputs of respective first AND gates; a path time delay adjustment circuit, with an input receiving a pulse signal, and an output connected to an input terminal of the first buffer; a control apparatus, controlling the time delay produced by the adjustment circuit to be reduced by at least one step from a preset time delay during each adjustment until an output of a P.sup.th flip-flop flips; a measuring device measuring the pulse signal's width according to an output of each flip-flop, the time delay of each first buffer and the time delay of the adjustment circuit.

What is proposed is a method for accurately determining an electric current (I.sub.in, I.sub.in,0) with reduced technical outlay, comprising: connecting a circuit branch (2, 12) in parallel with an inaccurate but current-loadable shunt resistor (R.sub.sh), wherein a reference resistor (R.sub.ref) that is more accurate in comparison with the shunt resistor (R.sub.sh) but less current-loadable is connected into the circuit branch (2, 12), such that the circuit branch (2, 12) branches off in each case at a node point (K) upstream and downstream of the shunt resistor, generating a temporally changeable reference current (I.sub.ref, I′.sub.ref, I″.sub.ref) through the circuit branch (2, 12), measuring the voltages (V′.sub.sh, V″.sub.sh, V′.sub.ref, V″.sub.ref) across the shunt resistor (R.sub.sh) and across the reference resistor (R.sub.ref), determining the current strength (I.sub.in, I.sub.in,0) upstream and downstream of the node point (K).

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.

Testing apparatuses, and methods for using such apparatuses to calibrate and test an antenna, include a chamber that includes a lining, the lining being made from a material that is absorptive to radiation at a test wavelength. An adjustable platform is positioned at a first side of the chamber, the adjustable platform being rotatable to change an orientation of a device under test. A probe is positioned at a second side of the chamber, opposite to the first side of the chamber, that measures electromagnetic radiation from the device under test. A vector network analyzer communicates with the device under test and the probe to determine calibration information for the device under test.

A method, system and apparatus for compensating for non-ideal isotropic behavior of a field probe are disclosed. A method includes, during a calibration procedure, for each of a plurality of positions of the field probe relative to a source, each position denoted by a set of angles (θ, ϕ), performing the following steps: measuring a field by the sensors of the probe, storing the measurements and the set of angles (θ, ϕ) for each measurement, computing a correction factor for the set of angles (θ, ϕ) based on the measurement, and storing the correction factors. During a measurement procedure, each sensor measures a component of the field. A set of angles is determined based on the sensor measurements, and a correction factor is determined based on the set of angles. The correction factor may then be multiplied by the sensor measurements to obtain the corrected field measurements.

The present disclosure discloses a current detecting circuit of a power converter, which includes a transformer including: a magnetic core, a primary winding and a secondary winding, the primary winding and the secondary winding being coupled through the magnetic core, and a combination of the primary winding, the secondary winding and the magnetic core being used to transmit a main power of the power converter, the current detecting circuit includes: an auxiliary winding coupled to the secondary winding, the auxiliary winding and the secondary winding having the same number of turns and their dotted terminals being connected; and an impeder, one end thereof being coupled to the auxiliary winding to form a series branch, which is coupled in parallel to the secondary winding, and a terminal voltage of the impeder after being filtered being proportional to a magnitude of an output current of the power converter.