Electrolytic capacitors feature one: the capacitance per unit volume is very large, dozens to hundreds of times larger than other types of capacitors.

Electrolytic capacitor characteristics two: the rated capacity can be very large, can easily do tens of thousands of μf or even a few f (but can not be compared with the double layer capacitance).

The price of electrolytic capacitors has an overwhelming advantage over other types, because the constituent materials of electrolytic capacitors are ordinary industrial materials, such as aluminum and so on. The equipment for manufacturing aluminum electrolytic capacitors is also ordinary industrial equipment, which can be mass-produced and the cost is relatively low.

Aluminum electrolytic capacitor will be broken, it is only a matter of time. There are many reasons that affect the life of the capacitor, overvoltage, reverse voltage, high temperature, rapid charge and discharge, etc., under normal use, the biggest impact is the temperature, because the higher the temperature, the faster the evaporation loss of the electrolyte. It should be noted that the temperature here does not refer to the ambient or surface temperature, but to the working temperature of the aluminum foil. Manufacturers usually label the capacitor life and test temperature on the capacitor body.

Because the working temperature of the capacitor increases by 10 ° C, the life of the capacitor is halved, so do not think that the aluminum electrolytic capacitor with a life of 2000 hours is better than that of 1000 hours, and pay attention to the test temperature to confirm the life. Each manufacturer has a calculation formula for temperature and life, which should be calculated with reference to actual data when designing capacitors. It is necessary to understand that to improve the life of aluminum electrolytic capacitors, the first to reduce the working temperature, away from the heat source on the PCB, the second to consider the use of the highest working temperature of the capacitor, of course, the price will be higher.

Electrolytic capacitor in the circuit to withstand the actual voltage can not exceed its withstand voltage value. In the filter circuit, the voltage withstand value of the capacitor should not be less than 1.42 times the effective value of the AC. When using electrolytic capacitors, pay attention to the positive and negative terminals do not connect. Different circuits should use different types of capacitors. Mica and high-frequency ceramic capacitors can be used in the vibration loop, paper, polyester, mica, electrolytic and ceramic capacitors can be used for DC isolation, electrolytic capacitors can be used for filtering, and polyester, paper, ceramic and electrolytic capacitors can be used for bypass. Before the capacitor is loaded into the circuit, check whether it has short circuit, open circuit and leakage phenomenon, and check its capacitance value. When installing, it is necessary to make the symbol of the category, capacity and voltage resistance of the capacitor easy to see for verification.

life expectancy: The time of sustainable operation of the electrolytic capacitor at the highest working temperature.

lx=lo*2(to-ta)/10

lx= actual service life

lo= Guaranteed life

to= Maximum operating temperature (85℃105℃)

ta= the actual operating ambient temperature of the capacitor

example: The standard value is 105℃/1000hrs

Life estimation at 65℃ : lx=1000*2(105-65)/10

Actual working life: 8000hrs

The high temperature load life (load life) will be the electrolytic capacitor at the highest operating temperature, Inca rated operating voltage, after a continuous specified completion time, must meet the following changes: δcap: before the test value within 20%.