A self-developed “Standard Capacitance Box Output Device” has obtained national patent of America


Our invention of “Standard Capacitance Box Output Device” was granted United State Patent (US Patent # US9,208,944 B2) in November 8, 2015. The term of this patent is 20 years.


This new invention results in using less number of standard capacitors, simplifying the structure of changeover switch, and reducing the parasitic in the capacitance standard box, which lowered the error to less than ±8ppm (±0.0008%) and achieved very high precision capacitance box at ±10ppm (±0.001%). The certificate of this US patent is as below.