Capacitance: Constant discharge measurement

1. Dc voltage of constant current/constant voltage source is set as rated voltage (UR);

2. Set the constant current value of  specified constant current discharge device;

3. Switch the switch S to dc power supply and charge at constant voltage for 30min after constant current/constant voltage source reaches rated voltage;

4. At the end of 30min of charging, switch S is transformed to a constant discharge device, which is discharged at a constant current

5. Measuring the time t1 and t2 of voltage from U1 to U2 at both ends of the capacitor, as shown in the figure, calculate capacitance using the following formula。：

Equivalent series resistance:

Ac impedance measurement method

ESR shall be measured from the circuit below ：

ESR Ra can be calculated from the formula ：

Ra : equivalent series resistance（mΩ/Ω）；

U Ac voltage valid values（V r.m.s）；

I Ac current valid values（V r.m.s）。

Leakage Current：

ESR shall be measured from the circuit below

1、Discharge：Before the start of the measurement, supercapacitor should be fully discharge, discharge process for 1 h to 24 h.

2、Leakage current measurement shall be carried out under the rated temperature and voltage rating（UR）.The voltage of product reached 95% rated voltage after the biggest charging time for 30min，Charging time chooses from 30min，1h，2h，4h，72h。

3、Should use a stable power supply, such as DC regulated power supply.

4、Charge process should be through the protection under 1000Ω resistance.

Self-discharge

Before the start of the measurement ，super capacitor should be fully discharge, discharge process for 1 h to 24 h. Charge the super capacitor to rated voltage without protection

Resistance, charging time for 8h(include the voltage of product reached 95% rated voltage after the biggest charging time for 30min ).Disconnect the super capacitor from  the power supply. Super capacitor should be placed in the standard atmospheric pressure conditions for 24 h. Dc voltmeter internal resistance should be greater than 1 mΩ