This tool calculates the Quality Factor of a Capacitor. As the name suggests the higher the numerical value, the better the quality of the component.

## Formula

**Q = 1/(2π*f*C*ESR)**

where,

**f**= Frequency**C**= Capacitance**ESR**= Equivalent Series Resistance

The Dissipation Factor **DF = 1/Q**.

## Background

The quality factor **Q**, is a dimensionless number that is equal to the capacitor’s reactance divided by the capacitor’s equivalent series resistance (ESR).

**Q = X _{C}/ESR**

An ideal capacitor has an ESR = 0. In that case Q = ∞. However in practice 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.

The picture below shows Q vs Capacitance of a 1000 pF capacitor intended for RF applications.

For a fixed value of capacitance:

- Q decreases with increasing frequency
- ESR increases with frequency.

**Example Calculation**

A capacitor with an ESR of **0.2 Ω**, capacitance **10 μF** and Frequency **120 Hz** has a Quality Factor **Q = 663**.

## Summary

**The Quality Factor (Q) of a Capacitor **refers to its ability to store and release energy efficiently.

It is a measure of the ratio between the maximum energy stored in the capacitor and the energy dissipated per cycle.

Q is determined by various factors such as the capacitance, reactance, and operating frequency of the circuit. A higher Q signifies a more efficient capacitor. In an ideal capacitor, Q would be infinite, meaning that no energy is dissipated during operation.

However, in practical capacitors, energy dissipation is inevitable due to factors such as internal resistance and dielectric losses.

**Book Recommendation**

**Interested in learning more about Electronics?**

We recommend checking out the Art of Electronics.