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• Simplifies calibration/verification of precision calibrators and current sources
• Shunts sized for currents from 1mA to 100A
• Usable from dc to 100 kHz
• 14 individual shunts with a 1, 2, 5 sequence over 6 decades of current
• Simple direct measurements, making ac/dc transfers unnecessary
• Stability typically better then ± 5.0 µΩ/Ω for one year
• Typical angular accuracy of better than ± 0.003º at 1 kHz

Application

The wide range of shunt values permit measuring from 0.1mA 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.

Technical overview

The shunts come in four different sizes. The full set includes:

• four fully enclosed shunts: 1 mA, 10 mA, 20 mA, 50 mA
• five small size radial shunts: 100 mA, 200 mA, 500 mA, 1 A, 2 A
• three medium size radial shunts: 5A, 10 A, 20 A
• two large size radial shunts: 50 A, 100 A

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 shunt design gives high performance with minimum external magnetic fields. Plus, the open nature of the 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 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.

Reports of calibration

The A40B series of precision current shunts come standard with a report of traceable calibration including data. 17025A Accredited reports of calibration are available as an optional service.