CapacitanceRISE provides calibration services for capacitance standards (capacitance and dissipation factor) and various types of instruments, such as bridges, electrometers, calibrators and LCR-meters.
The unit of capacitance
The unit of capacitance, the farad (F), is realised in the range 1 nF – 3 nF depending on the measurement frequency with traceability to the units of resistance and frequency. The realisation is performed with a so-called quadrature bridge. The measurement uncertainty is of the order of 1 μF/F for the realisation of the capacitance unit at 1 kHz.
The realised capacitance unit is transferred to a group of 100 pF primary standards maintaining the capacitance unit. Between realisations, the primary standards are compared regularly to secure the maintenance of the capacitance unit. Secondary standards in the range 1 pF – 100 µF are calibrated with bridge measurements from the primary standards.
The dissipation factor D (tan δ) is realised at 100 pF with a method based on a variable parallel plate capacitor with traceability to the units for frequency, resistance and capacitance and is maintained by the primary capacitance standards. The measurement uncertainty is of the order of 0,5E-6 for the realisation of the dissipation factor. Secondary standards in the range 1 pF – 100 µF are calibrated with bridge measurements from the primary standards.
In order to further secure traceability, we also participate regularly in international comparisons.
We offer calibration of capacitance standards and different types of instruments such as resistance bridges, multimeters, calibrators and LCR-meters in the range 100 fF – 1 mF. Capacitance standards are calibrated with so-called substitution measurement in the range 1 nF – 10 µF with LCR-meter with measurement frequencies up to 10 kHz. The best measurement capability at 1 kHz is 10 μF/F.
Calibration of capacitance standards up to 10 kHz is also offered with capacitance bridge measurements for lower measurement uncertainty. The best measurement capability is 3 μF/F for capacitance and 3E-6 for dissipation factor calibrations.
Capacitance bridges and LCR-meters are calibrated by measuring on secondary capacitance standards at frequencies up to 10 kHz (in some cases above 10 kHz).
Calibration of high-voltage capacitors is offered up to 300 kV and 50 Hz (see high-voltage).
Other types of measurements are also performed, for example, determination of temperature coefficients.
The final uncertainty given at calibration depends not only on the uncertainty contribution from the calibration equipment but also from the device under test (stability, temperature coefficient, voltage dependence, etc.). A preliminary measurement uncertainty can often be estimated from experience prior to calibration.