The uncertainty measurement is an independent parameter to express the dispersity of measured value. In case of sound power measurement of capacitor unit

the meaning will be complete when both the measured value and related measurement uncertainty of the value are given. In case of the uncertainty analysis of sound of capacitor

the total measurement uncertainty is divided into the component caused by measurement method and component caused by unstability of the sound radiation of the tested object to set up uncertainty model of the sound power of capacitor unit. It is shown by the analysis of general condition that

in case of accuracy measurement

the uncertainty due to unstability of sound radiation of capacitor unit is 0.3 d B

and due to measurement method is 0.5 d B and the extend uncertainty is 1.2 d B at 95% confidence degree.