The capacitors are Andeen-Hagerling Model 11A with fused-silica dielectric, housed in a model 1100 frame with integral temperature control.
Measurement frequencies: 1.0kHz, 1.233kHz, 1.592kHz, 2.466kHz and 12.33kHz. Also 398Hz and 796Hz.
Resolution = 1 in 10^8 for Capacitance, 1 x 10^-8 for Dissipation Factor.
Uncertainties appropriate to the individual laboratories capability.
For Capacitance = 1ppm to 0.1ppm and for Dissipation Factor = 1 x 10^-5 to 1 x 10^-6.
Establishing the same unit of capacitance in various national laboratories within Europe is important:
1) To establish to what extent there are divergences in the representation of the farad.
2) To provide a sound basis for forthcoming AC measurement relating the Quantum Hall effect to capacitance (via a quadrature bridge).
3) For Calculable Capacitor determinations of the von Klitzing constant.
4) For force measuring electrometers which relate mass to the electrical units.
No exercise of this type has been carried out for many years.