Development of an Automated Precision Direct Current Source for Generation of pA Currents Based on Capacitance Charging Method at CSIR-NPL
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The design and development of a direct current source for picoampere currents based on capacitance charging technique at CSIR-NPL is presented. A highly linear voltage ramp generator has been realized which can generate ramps with any rate between ±1 and ±100 mVs−1. The ramp generator is computer controlled where the amplitude, slope and duration can all be controlled in software developed in LabVIEW which greatly simplifies the hardware configuration while providing great operational flexibility. The experimental evaluation of the current generator in the range from 1 to 100 pA indicates satisfactory performance. This work aims at developing a facility to ensure that CSIR-NPL can provide traceable calibration for picoammeters and electrometers.
KeywordsCapacitance charging Current generator Ramp generator Calibration Electrometer
The authors would like to extend their gratitude to Dr. V.N. Ojha, Head Apex Level Standards and Industrial Metrology (ALSIM), NPL for his constant support and encouragement. Thanks are also due to director NPL for providing all the facilities. Authors would also like to express their gratitude to the anonymous referees for their valuable comments to improve the manuscript.
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