This tool calculates the Dissipation Factor of a Capacitor.
Enter:
- ESR
- Capacitance
- Frequency of operation
Formula
D = ESR/|Xc|
D = (2π*f*C*ESR)
where,
- Xc = Capacitor Impedance
- f = Frequency
- C = Capacitance
- ESR = Equivalent Series Resistance
Background
Dissipation Factor (DF) is a measure of a capacitor’s dielectric losses. DF refers specifically to losses encountered at low frequencies, typically from 120 Hz to 1 kHz.
At high frequencies, capacitor dielectric losses are described in terms of loss tangent (tan δ). The higher the loss tangent, the greater the capacitor’s equivalent series resistance (ESR). In addition, the lower its Quality Factor (Q), the greater the losses (more heat dissipated) and the worse its noise characteristics.
The dissipation factor is a dimensionless number that is equal to the the capacitor’s equivalent series resistance (ESR) divided by its reactance. It is the inverse of the cap’s Quality Factor.
DF = 1/Q
An ideal capacitor has an ESR = 0. In that case D = 0.
However in the real-world, the series resistance is never zero. Ideally this value is kept as small as possible to minimize losses.
Typical quality factor values of a Capacitor advertised as having High Q are shown below.
Using the calculator above, a capacitance of 1000 pF, Frequency 1 kHz and ESR of around 16 Ω gives a Q = 10,000 and D = 1*10-5
Example Calculation
A capacitor with an ESR of 0.2 Ω, capacitance 10 μF and Frequency 120 Hz has a Dissipation Factor DF=0.0015.