Investigation of the Calibration Signal of Force Measuring Devices

Abstract

In international comparison measurements of force standard machines, the uncertainty of measurement is limited in essence by the uncertainty of measurement of the transfer standards, i.e. force transducer and measuring instrument. Separate investigations are necessary in order to allow the individual influences to be distinguished. The problems encountered in connection with force transducers as, for example, rotation and overlapping effect have been reported on repeatedly /1,2/.

For calibration of the measuring instrument, the transducer is replaced by a so-called bridge standard which allows de-fined voltage ratios to be realized and applied to the measuring instrument. Bridge standards comprise either resistance dividers (suitable for alternating and direct current) or transformers (suitable only for alternating current), the voltage ratio 2 mV/V being the calibration signal most frequently used. In the present paper a special measuring device for the calibration of bridge standards will be presented with which voltage ratios of about 2 mV/V can be determined with a relative uncertainty of 5 · 10⁻⁶ The measuring frequency is 225 Hz, input voltages of 5 V to 10 V are possible.