The loss of capacitor is made up of such two parts as dielectric loss and metal loss and tangent of loss angle（tanδ）is important technical parameters of metalized film capacitor. If the reason of which the loss exceeds the specified value can be found out by test

it will be helpful in sustaining improvement of the product quality. The reason of tanδ exceeding the specified value can be qualitatively judged by way of simplifying the equivalent circuit of capacitor and of using measurement analysis at different frequencies and

at the same time

the product’s consistency and increment after the test in the measurement of tanδ metalized film capacitor should be focused and such idea as ‘the smaller the better’should be changed.