1 A and 120 mA Thin-Film Multijunction Thermal Converters

Laiz,; Wunsch,; Kinard,; Lipe,

doi:10.1109/cpem.2004.305308

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…The detrimental characteristics of the sampling techniques and the TCs can be almost entirely eliminated by the synchronous synthesis and simultaneous sampling technique [1,2]. Of particular interest is the use of this technique at low frequencies (direct current (dc) to about 400 Hz), especially at frequencies below 10 Hz where the mass of the TCs no longer ensures the desired averaging effects [5].…”

Section: Introductionmentioning

confidence: 99%

Ac–dc transfer measurements of highest accuracy with synchronous analogue-to-digital conversion

Ihlenfeld¹,

Mohns²

2004

Metrologia

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This paper describes mathematical models for estimating measurement uncertainties of a new sampling primary standard for maintaining traceability of alternating current (ac) quantities to the time-invariant (or direct current (dc)) quantities of the International System of Units at the Physikalisch-Technische Bundesanstalt (PTB). A high-resolution analogue-to-digital conversion is used to determine effective values of ac quantities at low frequencies with uncertainty of some microvolts per volt and short measurement times. The system operates according to the synchronous generation and simultaneous analogue-to-digital conversion technique (Ramm G et al 1999 A new scheme for generating and measuring active, reactive and apparent power at power frequencies with uncertainties of 2.5 × 10 −6 IEEE Trans. Instrum. Meas. 48 422-6 [1], Kürten Ihlenfeld W G 2001 Maintenance and traceability of ac voltages by synchronous digital synthesis and sampling PTB Report E-75, Braunschweig [2]), and extensive comparisons with the primary thermal converters of the PTB show that the sampling system and the ac-dc thermal transfer technique agree within about ±0.5 µV V −1 .

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Section: Introductionmentioning

confidence: 99%

Ac–dc transfer measurements of highest accuracy with synchronous analogue-to-digital conversion

Ihlenfeld¹,

Mohns²

2004

Metrologia

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“…We should expect deviations from square and inversesquare laws that rule AC-DC differences at low frequencies in such standards to be related mainly to Thomsom heating and non-linear contributions to emissivity and thermal diffusivity in the heater [2,5,6,10,13], as well as non-linear contributions from circuitry in electronic standards, though the contribution of sistematic fluctuations of statistical nature should also be investigated.…”

Section: Results For Pmjtc Datamentioning

confidence: 99%

Power-law picture for the interpolation of AC-DC differences in thermal standards

2010

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In this work we present a general method, commonly applied to the numerical analysis of stochastic models, to interpolate AC-DC differences (usually denoted by the greek letter δ) between calibration points in thermal transfer standards. This method assigns a power-law behaviour to AC-DC differences, solely under the assumption that δ must be some smooth-varying function of voltage and frequency. We argue it may be straightfowardly applied to all working ranges of the standards, with no distinction.

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“…The methods used so far rely on the assumption that the ac-dc transfer differences at low frequencies (i.e. less than 50 Hz for PMJTCs with obelisks) are proportional to the input power, as shown in [2] and modeled in [3].…”

Section: Introductionmentioning

confidence: 99%

Verification of low frequency ac–dc transfer differences of thermal converters using sampling with sine-wave fit

Funck¹,

Spiegel²

2015

Meas. Sci. Technol.

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Thermal converters show significant ac–dc transfer differences at low frequencies due to nonlinearities of the heat transport mechanism and of the thermal-to-electric conversion. It is assumed that the ac–dc transfer differences at low frequencies are proportional to the input power. We have proved this assumption by an independent method with sampling techniques. A novel approach based on sine-wave fitting is used to calculate the RMS value of the sampled signal from the samples. It makes use of the low noise in a metrological environment. Expanded uncertainties in the order of 1.2 μV/V have been achieved.

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1 A and 120 mA Thin-Film Multijunction Thermal Converters

Cited by 5 publications

References 4 publications

Ac–dc transfer measurements of highest accuracy with synchronous analogue-to-digital conversion

Ac–dc transfer measurements of highest accuracy with synchronous analogue-to-digital conversion

Power-law picture for the interpolation of AC-DC differences in thermal standards

Verification of low frequency ac–dc transfer differences of thermal converters using sampling with sine-wave fit

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