Aluminum Electrolytic Capacitors (Radial lead Type)

1. Circuit design

1.1 Operating temperature and frequency

Electrical characteristics of the capacitor are likely to change due to variation in temperature and/or frequency.

Circuit designers should take these changes into consideration.

(1) Effects of operating temperature on electrical parameters

At higher temperatures : leakage current and capacitance increase while equivalent series resistance

(ESR) decreases.

At lower temperatures : leakage current and capacitance decrease while equivalent series resistance

(ESR) increases.

(2) Effects of frequency on electrical parameters

At higher frequencies

: capacitance and impedance decrease while tan d increases.

At lower frequencies

: heat generated by ripple current will rise due to an increase in equivalent

series resistance (ESR).

1.2 Operating temperature and life expectancy

(1) Expected life is affected by operating temperature. Generally, each 10 ℃ reduction in temperature will

double the expected life. Use capacitors at the lowest possible temperature below the upper category

temperature.

(2) If operating temperatures exceed the upper category limit, rapid deterioration of electrical parameter

will occur and irreversible damage will result.

Measure not only the ambient temperature but also the surface temperature of the capacitor’s case top,

which has effects of ripple current and radiated heat from power transistors, IC's, and/or resistors.

Avoid placing components, which could conduct heat to the capacitor from the back side of the circuit board.

(3) A formula for calculating expected life is as follows ;

L2 = L1×2

where T1 ≧ T2

L1 ：Guaranteed life (h) at temperature, T1 ℃

L2 ：Expected life (h) at temperature, T2 ℃

T1 ：Upper category temperature (℃) for the series, GA-A, M-A, and SU-A

Upper category temperature + temperature rise due to rated ripple current (℃) for the other series

T2 ：Actual operating temperature, ambient temperature + temperature rise due to ripple current (℃)

(4) Using the capacitor beyond the rated lifetime will result in short circuit, electrolyte leak, vent open, and large

deterioration of characteristics. The lifetime cannot exceed 15 years due to aging of sealing rubber.

1.3 Load conditions to avoid

The following load conditions will cause rapid deterioration of capacitor’s electrical characteristics.

In addition, instantaneous heating and gas generation within the capacitor may cause an operation of pressure

relief vent, and that results in electrolyte leaks, explosion and/or fire ignition.

The leaked electrolyte is combustible and electrically conductive.

(1) Reverse voltage

DC capacitors have polarity. Therefore, do not apply the reverse voltage. Find the correct polarity before insertion.

(2) Charge / Discharge applications

General purpose capacitors are not suitable for use in repeating charge/discharge applications.

For such applications, consult a sales representative with actual application condition. Rush current must not

exceed 100 A.

(3) ON-OFF circuit

When using capacitors in circuit where ON-OFF switching is repeated more than 10,000 times a day,

consult a sales representative with actual application condition for an appropriate choice of capacitors.

(4) Over voltage

Do not apply a voltage exceeding the rated voltage. The rated surge voltage can be applied only for a short time.　　

Make sure that a sum of the DC voltage and the superimposed AC ripple voltage does not exceed the rated

voltage.

01-Oct-21

　　Application guidelines（Radial lead Type）

T1-T2

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