Functions and main characteristic parameters of Electrolytic capacitor

Electrolytic capacitor is widely used in life, so what is Electrolytic capacitor? In fact, Electrolytic capacitor is a kind of capacitor. The metal foil is positive (aluminum or tantalum), and the dielectric is close to the positive metal oxide film (aluminum oxide or Tantalum pentoxide). The negative electrode is composed of conductive materials, electrolytes (which can be liquid or solid), and other materials. Electrolytic capacitor is famous for its electrolyte is an important part of negative electrode. At the same time, the positive and negative of the Electrolytic capacitor cannot be connected incorrectly.

Important characteristic parameters of Electrolytic capacitor

1. Standard capacity and allowable error

1. Standard capacity is the capacity marked on a capacitor, and the error between the specific capacity of the capacitor and the standard capacity is called deviation, and within the allowable deviation range is called accuracy.

2. The accuracy level is related to the allowable error: 00 (01) - ± 1%, 0 (02) - ± 2%, I - ± 5%, II - ± 10%, III - ± 20%, IV - (20% -10%), V - (50% -20%), VI - (50% -30%)

3. Common capacitors are Class I, II and III, and Electrolytic capacitor are Class IV, V and VI, which are selected according to the purpose.

2、 Rated current

The maximum DC voltage effective value of a capacitor can continue to increase at the minimum operating temperature and rated operating temperature, usually directly marked on the capacitor casing. If the working voltage exceeds the compressive strength of the capacitor, the capacitor will penetrate, causing irreparable permanent damage.

3、 Insulation resistance

The DC voltage is added to the capacitor and generates leakage current, which is called insulation resistance. When the capacitor is small, it depends entirely on the Surface states and volume of the capacitor>0.1uf When it depends entirely on the dielectric characteristics, the greater the insulation resistance, the better. Steady-state value of capacitors: Introduce steady-state values to appropriately evaluate the insulation state of large space capacitors, equivalent to the insulation resistance and capacity of capacitors.

4、 The energy consumed per unit time due to heating under the influence of an electric field is called consumption. Various capacitors have specified values for their consumption within a certain frequency range. The consumption of capacitors is mainly caused by dielectric loss, conductivity consumption, and the resistance of all metal components of the capacitor. Under the influence of a direct current electric field, the consumption of capacitors exists in the form of leakage loss, which is generally small. Under the influence of alternating electric fields, the consumption of capacitors is not only related to leakage, but also to the process of periodic polarization creation.

5、 Frequency characteristics

The capacitance of a general capacitor decreases with increasing frequency.

Features of Electrolytic capacitor

1. The capacity per unit volume is particularly large, tens to hundreds of times larger than other types of capacitors.

2. The Nameplate capacity can be very large, which can easily reach tens of thousands μ F or even several f (but not comparable to Supercapacitor).

3. Compared with other types, the price has an overwhelming advantage because Electrolytic capacitor are composed of ordinary industrial materials, such as aluminum. The machine for manufacturing Electrolytic capacitor is also an ordinary industrial equipment, which can be produced in large scale with relatively low cost.

Efficacy of Electrolytic capacitor

1. Filtering effect

In the power supply circuit, the rectifier circuit converts AC into pulse DC, but after the rectifier circuit is connected with a large capacity Electrolytic capacitor, its charge discharge characteristics are used to convert the pulse DC voltage after rectification into a relatively stable DC voltage. In fact, in order to avoid the power supply voltage of various circuit components changing due to load changes, the power supply output end and the power supply input end of the load usually receive tens to hundreds of microf Electrolytic capacitor. Since large capacity Electrolytic capacitor generally have a certain inductance, they cannot filter high-frequency and pulsed electromagnetic interference effectively, so the capacity on both sides is 0.001-0. LPF capacitors that filter high-frequency and pulsed interference

2. Coupling effect

In the process of low-frequency signal transmission and amplification, in order to avoid the interaction between the static operating points of the front and rear secondary power supplies, capacitance lotus root is often used. In order to avoid excessive loss of low-frequency components in the signal, Electrolytic capacitor with large volume is generally used.

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