Calculation Details of Capacitance Loss

Capacitance loss refers to the energy loss of a capacitor during operation due to the passage of current. It can be calculated based on the phase difference between the voltage and current of the capacitor. In an AC circuit, the capacitive reactance Xc of the nominal capacitance C is determined by the formula Xc = 1/ωC, where ω = 2πf (f is the current frequency). When a resistive element and a capacitive element are connected in parallel, the total reactance Z_total can be calculated by the formula Z_total = (R² + Xc²)^(1/2), that is, Z_total = (R² + 1/ω²C²)^(1/2), with R being the resistance value, and the capacitor current I_c = V/Z_total (V is the voltage).

There are various calculation methods for capacitance loss. The tangent of the capacitance loss angle (tanδ) is equal to the ratio of the capacitive reactance Xc to the resistance R, that is, tanδ = 1/(2πfRC). The power density of capacitance loss (P_loss) is equal to the square of the current I_c multiplied by the resistance R, which can also be expressed as P_loss = (V²)/(R·(R² + 1/ω²C²)). The quality factor Q and the capacitance loss factor D are calculated as follows: Q = 1/(2πfRC) = 1/tanδ, and D = Q/(1 + Q²).

In actual calculations, it is necessary to clarify the capacitance value C, voltage V, current frequency f, and loss resistance R. Relevant data of the capacitance value and loss resistance can be obtained through model parameters and other channels. The voltage and frequency are selected according to the scenario, and instruments such as an oscilloscope can be used for measurement and calculation. Since capacitance loss has a significant impact on circuit performance, it is necessary to calculate it reasonably during circuit design and select