Maintaining the Traceability of an Active Capacitance Source

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Maintaining the Traceability of an Active Capacitance Source (139.51 KB)

A high accuracy active capacitance source relies on a number of fixed capacitors that act as references. Because these capacitors suffer a small amount of drift with time and temperature, a novel impedance transfer technique has been developed to provide automatic drift compensation. This technique relates the capacitance values to voltage, resistance and time references which have much better stability than the capacitors themselves. Being based on the fundamental equation C = I x t/V the impedance transfer is fully traceable. Traceability can be demonstrated by direct comparison of the active capacitance source against external standards.