CSIR-National Physical Laboratory

सीएसआईआर-राष्ट्रीय भौतिक प्रयोगशाला

LF, HF Impedance and DC Metrology

This activity is maintaining the LF & HF impedance standards, DC standards and DC High Voltage standards.

LF & HF Impedance Standard: This activity is maintaining the standards of capacitance, inductance and ac resistance. Value to the 10 pF capacitor is assigned through primary standard, calculable cross capacitor, with an uncertainty of 0.6 ppm using precision ac bridges. Scale of capacitance is build up from 10 pF to 1 F using transformers bridges. The unit of inductance, Henry, is realized from capacitance and resistance using Maxwell-Wien bridge. Value to 100 µH to 10 H is assigned through this bridge. The unit of ac resistance, Ohm, is also realized from capacitance, using Quadrature Bridge and other precision ac bridges at