Low esr capacitor: measuring method of capacitance and low resistance by low frequency

Accoring to 62391-1© IEC:2006(E) ,This method is suitable for low esr capacitor (capacitors with relatively low internal resistance), and can be used as a shortcut method to reduce the measuring time .

Measuring method of capacitance and low resistance-Low esr capacitor

Measuring system

The mesuring system includes the components in figure B.1. The system that replaces this method for measuring capacitance at low frequency may be used.

  1. Generate a sinusoidal voltage at the specified frequency with a frequency response analyzer and apply the voltage to a capacitor via a potentiostat;
  2. Detect the current that folws through the capacitor with a potentiostat (a device to automatically keep the electrode potential constant), and convert it into a voltage value to return it to the frequency analyzer.
  3. Obtain the impendance[Z]and phase angle Φ from the voltage and current of the capacitor to be measured.

Calculation of capacitance

  1. Calculate the reactance X by the following formula:
    Formula of calculate the reactance X-Low esr capacitor

X is reactance(Ω)

[Z] is impedance (Ω)

Φ  is the phase angle

  1. Use the calculated reactance to calculate the capacitance C of the capacitor by the follwing formula:calculate the capacitance C of low esr capacitor


C is capacitance (F);

π is the circle ratio;

f is the measuring frequency(Hz)

Measuring conditions

  1. Use any measuring frequency from 0.05Hz,0.1 Hz,1 Hz,10 Hz or 100 Hz.
  2. The measuring voltage shall be 3% or less of the rated voltage;
  3. The basis voltage shall be 50% to 95% of the rated voltage. If no doubt arises on judgment, bias voltage may be omitted.

About SPS

Supreme Power Solutions Co., Ltd. (SPS) is a leading manufacturer of ultracapacitors, as well as a provider of ultracapacitor energy storage systems and technological solutions. Our products have wide industry applications, such as new energy vehicles, wind turbines pitching control systems, trams and subways, smart grid, micro grid, heavy duty machineries, intelligent instrument, etc. We support more than 200 customers, and our products are exported to 26 countries and territories.

More information:https://www.spscap.com

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