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Understand the Capacitance Change When a Voltage is Applied to a Capacitor

Updated: Oct 4, 2020

One common question from our customers concerns the large errors created when measuring ceramic capacitors. In most cases, such errors come from the actual capacitance change when a voltage is applied on that ceramic capacitor. The actual capacitance of a ceramic capacitor is influenced by the dielectric constant (K) of the material used to make the ceramic capacitor. For high dielectric capacitors, such as X5R, X7R type, the capacitance varies significantly when the voltage applied on it varies.

For example, the chart below is the AC voltage vs capacitance for a X5R capacitor (Samsung X5R 10V 10uF ceramic capacitor, part number: CL21A106KPCLQNC)

As you can see, this capacitor has rated capacitance at 1.0V. At 0.5V, the actual capacitance has dropped by around 10%. If your #LcrMeter is set as 0.5V for measuring such capacitor, you will see “big error” comparing to the rated capacitance, but this is actually not an error. It just reflects the actual capacitance change. In order to avoid such “error”, we recommend the #LcrPro1 LCR meter users to check the capacitor’s datasheet and use the same test voltage and test frequency as the manufacturer does to perform capacitance measurement.

Reference: The voltage characteristics of electrostatic capacitance

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