Aluminum electrolytic capacitor * performance characteristics
Compared with other types of capacitor, the advantages of aluminum electrolytic capacitor in the following aspects:
(1) per unit volume of particularly large capacitance.The lower the working voltage, increasingly prominent feature of this, therefore, ADAPTS the miniaturization and large capacity of the capacitor.CD26 type low voltage, for example, the large capacity of aluminum electrolytic capacitor specific capacity of about 300 mu F/cm3, and the other in terms of miniaturization and characteristic of the metallized paper condenser low voltage chip ceramic capacitor specific capacity generally not more than 2 u F/cm3.
(2) in the working process of the aluminum electrolytic capacitors "self-healing" characteristics."Self-healing" feature refers to the medium of the oxide film defects or defects in the working process of the capacitor can be fixed at any time, restore its should have the insulation ability, avoid incur the avalanche of dielectric breakdown.
(3) the dielectric oxide film of aluminum electrolytic capacitor to withstand very high electric field intensity.In the working process of the aluminum electrolytic capacitor dielectric oxide film on the electric field intensity is about 600 kv/mm, that figure is more than 30 times the paper condenser.
(4) can get high electrostatic rated capacity.Low voltage aluminum electrolytic capacitor can be very conveniently to obtain the method of thousands or even tens of thousands of micro electrostatic capacity.In general, the power supply filter, ac bypass capacitor needed for the purposes only selects the electrolytic capacitor.
Aluminum electrolytic capacitor, of course, also have the following significant drawbacks:
(1) poor insulation performance.It can be said that the aluminum electrolytic capacitor is the worst in all categories of capacitor insulation.For aluminum electrolytic capacitors, usually leakage current is used to characterize its insulation performance, high voltage large capacity of aluminum electrolytic capacitor leakage current can be up to 1 ma.
(2) loss factor, low pressure aluminum electrolytic capacitor of DF is usually above 10%.
(3) the temperature of the aluminum electrolytic capacitor characteristics and frequency characteristics are poor.
(4) aluminum electrolytic capacitor has a polarity.Used in electronic circuits, aluminum electrolytic capacitor anode to meet potential high point in the circuit, the cathode potential low point, can play a normal electrical function.If meet the, capacitor leakage current increase sharply, core severe fever, cause the capacitor failure, and is likely to burning explosion, the other on the damage of circuit board components.
(5) working voltage with a certain limit.According to the special generation of aluminum electrolytic capacitor dielectric oxide film, its highest working voltage is 500 v, general and development potential is very limited;And for some other chemical capacitor, as long as appropriate and thicken the thickness of the dielectric, theoretical working voltage can reach any upper limit.
(6) the performance of the aluminum electrolytic capacitor easy degradation.Use after long-term storage of aluminum electrolytic capacitor, unfavorable suddenly impose rated voltage, and shall be gradually step up to the rated voltage.
(7) the traditional aluminum electrolytic capacitor with electrolyte as a cathode, there are many obstacles in the chip, so the chip process behind the ceramic capacitors and metallized film capacitor.
Aluminum electrolytic capacitor * advantages and disadvantages
Aluminum electrolytic capacitor:
Advantages - cheap (populist!), the rated voltage value high (only up to 450 v), strong ability to resist surge (1.3 times rated voltage under 60 s, very suitable for filtering)
Faults - short storage life (electrolyte increased leakage current increasing, the ESR value after volatilization, life more than for 2-3 years), the service life is different, the price is different (standard for 2000 hours, the longer the life, the higher the price), is highly affected by the temperature (temperature in the work of every 10 degrees height, life expectancy in half)