Improving the mechanical stability of a standard capacitor

CSIR, National Metrology Laboratory of South Africa, had manufactured 10-pF ultra-low expansion quartz capacitors that had been in use since the early 1970s. Although the capacitors were extremely stable and had low temperature coefficients of capacitance, they were susceptible to mechanical shock. The development of a standard capacitor with improvements to increase its robustness is presented. Results of the transportability test show that the design has improved the mechanical stability of the capacitor.