Measurement module (the current and voltage sensing front end of an electrical test bench)
The current-sensing front end of a test bench measurement module · shunts, Rogowski coils, Hall-effect and fluxgate (zero-flux) transducers compared on accuracy, range, bandwidth, DC capability and isolation, and the errors each brings
A test bench is only as good as its measurement of the current and voltage it applies. The measurement module inside it turns tens or thousands of amperes into a signal an acquisition system can read, and the sensor chosen sets the accuracy, the range, whether DC can be measured, how fast transients are followed, and whether the measurement is isolated from the circuit. Specify the currents, waveforms and accuracy needed first, then choose the sensor technology.
Current and voltage sensing for measurement modules in electrical test benches and test systems: shunts, Rogowski coils, current transformers, Hall-effect and fluxgate (zero-flux, DCCT) transducers, with their accuracy, range, bandwidth and isolation. The test benches and their tests are covered on the Power distribution test bench page; protection and metering CTs on the Current transformer page; complete instruments on the Power analyzer and Power quality analyzer pages; MV test rooms on the Final test chamber for medium-voltage switchgear panels page.
CNFX editorial research · Sources checked October 12, 2026 · 3 sources
Miguel Cerqueira Bastos of CERN compares current measuring devices in one table, from which the following rows are taken. [1]
Yokogawa's high current measurement guide says the fluxgate closed-loop zero-flux design "will generally provide the best linearity, accuracy, stability, and frequency response", used for benchmarking power measurements with switching waveforms where errors must be minimal ("error ≤ 1%"); Hall-effect clamps are for when "convenience is important" and "high accuracy is not a concern". [2]
Device
Accuracy
Range
Bandwidth
Isolation
Source
DCCT (zero-flux)
"Best devices can reach ppm uncertainty"
Tens of A to tens of kA
kHz at higher DC currents, up to a couple of hundred kHz at lower
List the currents (DC, 50/60 Hz, pulsed), the accuracy needed at each, the bandwidth of the events to capture, and the voltage between the measured circuit and the acquisition system.
02
Error sources to plan for
Rogowski coils, Yokogawa explains, produce a voltage from the change in current that must be integrated, so they "require a continuously changing (AC) or pulsed current in order to produce an output"; they "are very sensitive to conductor position; this error alone can contribute up to 2% of total error excluding other sources". [2] TI adds that because Rogowski coils have no metal core, "the mechanical tolerances of the positioning both influence and limit the ac"curacy. [3]
For shunts, TI notes that "their use is limited by the power dissipation caused by their own resistance value", and that with high common-mode voltages they need isolated amplifiers or isolated delta-sigma modulators. [3] CERN lists the shunt's resistance change with ambient temperature and with "internal temperature due to self-heating", the power coefficient of resistance and hysteresis under power cycling as error sources, and recommends Rogowski coils or coaxial shunts for bandwidths above some hundreds of kHz "as long as accuracy requirements remain around the percent figure". [1]
Ask the supplier for the uncertainty of the whole measurement chain (sensor, burden or integrator, amplifier, ADC) at the currents and frequencies tested, not the sensor figure alone.
03
Measurement module details
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Currents: [DC; AC 50/60 Hz; pulsed; max kA]
Accuracy: [% or ppm at each range]
Bandwidth: [Hz to kHz/MHz]
Voltage: [ranges; dividers]
Isolation: [working voltage between circuit and acquisition]
Sensor: [shunt; Rogowski; CT; Hall; fluxgate/DCCT]
Acquisition: [sampling; resolution; interface]
Calibration: [traceability; interval]
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
Which current sensor gives the lowest uncertainty?
CERN's table puts DCCTs at ppm uncertainty for the best devices, ahead of Hall transducers at 0.1% and CTs "Typically not better than 1% uncertainty". [1]
Can a Rogowski coil measure DC?
No; Yokogawa says it needs a continuously changing or pulsed current to produce an output. [2]
Why are Rogowski readings position-sensitive?
Yokogawa says conductor position alone can add up to 2% error. [2]
What limits shunts at high current?
TI points to power dissipation in the shunt; CERN lists self-heating and temperature coefficient effects. [3][1]
Sources and what still needs a direct check
Sources checked 2026-10-12. CERN's Miguel Cerqueira Bastos reviewed high-precision current measurement (arXiv); Yokogawa publishes a high current measurement application guide; Texas Instruments published a blog on six ways to sense current.
