The super capacitor (EDLC) differs from the battery in that the charge discharge potential decreases. Therefore, the energy that can be stored in the capacitor is represented by 1/2 of the product of Q (charge) V (voltage). However, due to the complicated construction of the supercapacitor electrode, the actually measured electrostatic capacitance varies depending on the charging conditions and the discharging conditions. Murata's supercapacitors are suitable for applications with large current output, so the nominal capacity is specified based on the measured value of 100 mA.

Nominal capacity calculation <discharge method>

Temperature conditions: 25 ° C +/- 5 ° C

In the circuit on the right, as shown in the diagram on the right,

Discharge after 30 minutes of charging at the highest rated voltage.

Charge / discharge current: 100mA

V80%: 80% of the maximum rated voltage

V40%: 40% of the maximum rated voltage

T1: Time to reach V80%

T2: Time to reach V40%

Id: discharge current (certain)

The capacity is calculated by the following formula:

Measuring circuit

ESR calculation <AC method>

The equivalent series resistance (ESR) is suitable for measurement by the alternating current method.

The voltage at both ends (Vc) of the capacitor through the 10 mA alternating current was measured and calculated by the following formula.

ESR calculation

Determination of temperature conditions: 25 ° C +/- 5 ° C

Measuring frequency: 1kHz

AC current (Ic): 10mA

Capacitor voltage: Vc

Measuring circuit