Influence of the adaptor on the calibration of 100 µH inductance standard has been studied using two different homemade adaptors of BPO gold-plated brass (BPO-Au) and banana-copper (BN-Cu) as a function of torque. The inductance (L) and the contact resistance (RC) showed an exponential decrease against the increasing torque from 25 cN·m to 150 cN·m. The measured L and the calculated equivalence series resistance are dependent on the type of adaptors as well as the RC. The analysis of RC and measurement uncertainty of L implies that the BPO-Au adaptor with low RC is suitable for the calibration of inductance. The measured L obtained using BPO-Au and subtracted by the RC agreed well with the certificate value of the PTB within the measurement uncertainty of 140 µH/H. In addition, the calculated inductance of the adaptors shows influence of the lumped components, stray capacitance and series resistance, on the measurements of standard inductors.

If accuracy matters, mechanical quantities such as force, torque or pressure are almost exclusively realized by transducers, which are based on strain gauges. To exploit the potential of static measurements the demands on precision amplifiers steadily grow. This paper gives some details to progress of the precision amplifiers used.

This paper aims to the characterization of non-idealities of the Pseudo Random Binary Sequence (PRBS) mixing the signal input in a Random Demodulation Analog-to-Information Converter (RD AIC). Once the PRBS has been characterized, a simulation analysis has been carried out in order to evaluate the error that each component of the jitter affecting the PRBS causes on the AIC output. Results show that significant error is also caused by deterministic jitter components that could be included in the AIC model.

The paper proposes a variant of adaptive sub-ranging ADC capable of self-calibration in presence of the internal amplifiers gains deviations due to technological imperfections. The changes needed to be implemented to make the adaptive ADC insensitive to gains errors, and the procedure of self-calibration that uses the internal DAC as calibration signal source, are proposed. Capabilities of the approach are discussed on the basis of results of computer simulations.

The characteristics of permanent magnets must be carefully controlled when applied in automotive, industrial and consumer products. In this paper we present a novel measurement system for quality control of permanent magnets by integrating magnetic field mapping and crack detection. The novel system is introduced that combines in a single device the features of a magnetic field mapper, the eddy-current measurements and a touch stylus. The magnetic field sensitive area of the 3D Hall probe is 100 x 100 µm; the selectable measurement range is 50 mT - 2 T; the probe positioning accuracy is 2 µm / 0.02°; and the measurement accuracy is 0.1%. The angular error of the sensitivity vectors of the 3D Hall probe are less than 0.1°. The system integrates various tools for in-situ automatic calibration, e.g. the precise determination of the magnetic field sensitive volume. The mapping system allows a smart and easy interchangeability of various measurement probes. Further in this paper we present several industrial applications that apply the novel measurement system for quality control of their permanent magnets and magnetized and non-magnetized parts: one application is the quality control of segment magnets for rotors; another application is crack detection in magnetized and non-magnetized parts; further applications include high-resolution magnetic field mapping of an area around permanent magnets in the form of a disc, block or electronic circuit PCB's such as smartphones or tablets.