Say the capacitor nine: the basic formula of the capacitor parameters

1, capacity (Fala)

Inch: C = ( 0.224 × K · A) / T _D

Metric: C = ( 0.0884 × K · A) / T _D

2. Energy stored in the capacitor

E = 1⁄2 CV ²

3, the linear charge of the capacitor

I = C (dV/dt)

4, the total impedance of the capacitor (ohms)

5, capacitive reactance (ohm)

XC = 1/(2πfC)

6, phase angle Ф

Ideal capacitor: advanced current voltage 90o
Ideal inductor: hysteresis current voltage 90o
Ideal resistor: the same phase as the current voltage

7. Dissipation coefficient (%)

DF = tan δ (loss angle)

= ESR / X _C

= (2πfC)(ESR)

8, quality factors

Q = cotan δ = 1/ DF

9, equivalent series resistance ESR (ohms)

ESR = (DF) X _C = DF/ 2πfC

10, power consumption

11, power factor

PF = sin δ (loss angle) – cos Ф (phase angle)

12. Root mean square

13, kVA KVA (kW)

KVA = 2πfCV ² × 10 ^-3

14, the temperature coefficient of the capacitor

TC = [ (C _t – C ₂₅ ) / C ₂₅ (T _t – 25) ] × 10 ⁶

15, capacity loss (%)

16, the reliability of ceramic capacitors

17, the capacitance value in series

18, the capacitance value in parallel

C _T = C ₁ + C ₂ + .... + C _n

19. Againg Rate

AR = % ∆C / decade of time

The symbols in the above formula are as follows:

K = dielectric constant A = area T _D = thickness of insulation layer V = voltage t = time R _S = series resistance f = frequency L = inductance inductive coefficient δ = loss angle Ф = phase angle L ₀ = service life L _t = test Lifetime V _t = test voltage V ₀ = operating voltage T _t = test temperature T ₀ = operating temperature X , Y = effect index of voltage and temperature.