The wide range of shunt values permit measuring from 0.1 mA to 100 Amps. The physical construction and the components used in the current shunts ensure that the frequency response is very flat (amplitude displacement error relative to dc resistance). Also the phase displacement at 100 kHz is small enough to be neglected in all but the highest accuracy measurements. Combined with excellent dc resistance stability, the shunts can be used to directly measure current through their full bandwidth. This simplifies precision ac current measurements as the complex ac/dc transfer measurement process will no longer be necessary for many precision current measurement applications. These characteristics make the A40B shunts ideal for traditional precision current applications such as calibrator verification. Also, the wide current range allows verification of high current transconductance amplifiers. The low phase shift error is critical for measurement of non-sinusoidal wave shapes, as found in power quality or sampling digital wattmeter measurement applications.
The shunts come in four different sizes. The full current shunt set includes:
Voltage output is nominally 0.8 volts for the nominal rated current input. The output is measured by a voltmeter or detector, such as precision voltmeters, ac measurement standards, ac/dc transfer standards, or thermal voltage converters, fitting them to a wide variety of metrology applications.
The radial style dc and ac current shunt design gives high performance with minimum external magnetic fields. Plus, the open nature of the dc and ac current shunt physical design maximizes air flow so the shunts have a minimal power coefficient effects. This permits each shunt to be used over a wide range of currents with stable resistance characteristics.
The dc and ac current shunt resistance is designed to minimize interaction with the detector instrumentation. The 100 Amp shunt resistance is 8 milliohms, with shunt resistance increasing to 80 ohms for the 10 mA shunt. Additionally, the 1mA shunt includes an internal battery operated buffer amplifier. It drives the output voltage so the 800 ohm shunt resistance has minimal interaction with the measurement device.
The A40B series of precision dc and ac current shunts come standard with a report of traceable calibration including data. 17025A Accredited reports of calibration are available as an optional service.
|The following table shows the 1-year absolute accuracy specification stated at k=2, approximately 95 % confidence for the calibrated value. The specifications include 1-year stability, temperature effects over TCal ± 1 °C, and the measurement uncertainty of the calibrated value.|
|Shunt Nominal Current:||Specification ± μA/A, TCal ±1 °C, ≤ 50 % RH 1,2,3,5|
|DC||1 kHz||100 kHz|
|1 The measured current is determined from: I = (V/Rcalibrated) ×(1 + (AC-DCcalibrated /1,000,000)); where AC-DC calibrated is expressed in ppm. 2 Above 1 kHz interpolate the specification (si) between frequencies fupperand flower using: si = slower + (fi – flower) × (supper – slower) ÷ (fupper – flower) 3 Add 20 μA/A if relative humidity is outside specification limits. 4 1 mA specifications apply with the battery charger disconnected. 5 Specifications assume no loading effects due to the voltage-sensing device. See Output Voltage Measurement – Loading Effects in the operating information.|
|Shunt Nominal Current:||Maximum AC-DC Difference (± ppm)1,2|
|1 kHz||100 kHz|
|1 Specifications indicate the maximum flatness deviation from dc, and include both measured AC-DC difference and the uncertainty of measurement. They are stated at k=2, approximately 95 % confidence. 2 Includes 1-year stability of the AC-DC difference. 3 Specifications for the 1 mA current shunt are for TCal ± 1 °C.|
|Calibration Documentation||17025 accredited report of calibration included|
|Storage and transit environments (for models other than the 1 mA current shunt)||
|Additional 1 mA current shunt specifications|
|Output resistance||8 mΩ|
|Maximum safe output current||11 mA (e.g., 1 V output into 90 Ω)|
|Maximum capacitive load||800 pF|
|Output voltage regulation||15 ppm/100 pF|
|Maximum output dc v offset||± 100 μV (typical ± 25 μV)|
|Typical error @ 1 MHz||< 2 %|
|Battery size||AAA (44.5 mm x 10.5 mm)|
|Battery technology||Nickel-Metal Hydride (NiMH)|
|Number of batteries required||8 (in 2 groups of 4)|
|Nominal battery voltage||1.2 V (4.8 V per group of 4)|
|Typical battery capacity||800 mAh|
|Storage and transit environment to preserve the batteries||
|Maximum operating time between charges||
|A40B-ADAPT/LC||LC Male to LC Male adapter|
|A40B-ADAPT/LCN LC||Female to N Male inter-series adapter|
|A40B-CAL/LC||High current adapter to connect two shunts in series for measurement (LC to LC)|
|A40B-CAL/N||Low current adapter to connect two shunts in series for measurement (N to N)|
|A40B-CASE||Fiberglass Transit Case|
|A40B-LEAD/4MM||N to 4 mm double banana connector|
|A40B-LEAD/N||N Male to N Male lead|