Abstract. Since the quantum Hall resistance (QHR) measured with alternating current (ac) has reached the state of an excellent quantum standard of impedance, we have realized a quadrature bridge with two ac QHRs to accurately calibrate capacitance standards in terms of the SI value of the von-Klitzing constant, without the need for any calculable artefact. The advantages of the realized measuring chain, experimental tests of the coaxial ac bridges involved and the achieved relative uncertainty of 6 × 10⁻⁹ (k = 1) are discussed.

Print publication: Issue 6 (December 2009)
Received 26 June 2009, in final form 30 August 2009
Published 7 October 2009