Electrometer Current Scale Calibrations

Current scales on electrometers are calibrated by measurement of a calibrated current source. The current source is calibrated at the time of the measurement by using a known capacitor and a timer. The customer electrometer is then connected to the current source, allowed to stabilize, and readings are taken allowing us to assign a calibration factor (A/Rdg) for each requested scale. The uncertainty in the calibration of current scales (generally dominated by the precision of the instrument) is 0.5%.