An improved two terminal-pair capacitance bridge at NIM

An improved two terminal-pair coaxial AC bridge with auto source balance is constructed at NIM for high precision capacitance measurement. The errors introduced by auto source balance in the bridge are at negligible level. The bridge can disseminate the calculable capacitance to 1 pF, and transmit capacitance from 1 pF to 10000 pF. A minimum standard uncertainty 7.7 × 10
^-9
is achieved at 1592 Hz.