- What is an electrolytic capacitor
Electrolytic capacitor is a type of capacitor. The metal foil is the positive electrode (aluminum or tantalum), and the metal oxide film (aluminum oxide or tantalum pentoxide) close to the positive electrode is the dielectric. The cathode is made of conductive materials and electrolyte (the electrolyte can be liquid or Solid) and other materials are composed together. Because the electrolyte is the main part of the cathode, the electrolytic capacitor is named after it. At the same time, the positive and negative electrolytic capacitors cannot be connected wrongly. Aluminum electrolytic capacitors can be divided into four categories: lead-type aluminum electrolytic capacitors; bullhorn aluminum electrolytic capacitors; bolt-type aluminum electrolytic capacitors; solid aluminum electrolytic capacitors. - Working principle of electrolytic capacitor
Electrolytic capacitors are usually made of metal foil (aluminum/tantalum) as the positive electrode, and the insulating oxide layer of the metal foil (aluminum oxide/tantalum pentoxide) as the dielectric. Electrolytic capacitors are divided into aluminum electrolytic capacitors and tantalum electrolytic capacitors based on their positive electrodes. Capacitor. The negative electrode of an aluminum electrolytic capacitor is composed of thin paper/film or electrolytic polymer immersed in an electrolyte solution (liquid electrolyte); the negative electrode of a tantalum electrolytic capacitor usually uses manganese dioxide. Since the electrolyte is used as the negative electrode (note that it is distinguished from the dielectric), the electrolytic capacitor gets its name. - Application of electrolytic capacitor
Polarized electrolytic capacitors usually play a role in power supply circuits or intermediate frequency and low frequency circuits for power supply filtering, decoupling, signal coupling, time constant setting, and DC blocking. Generally cannot be used in AC power circuits. When used as filter capacitors in DC power circuits, its anode (positive) should be connected to the positive terminal of the power supply voltage, and the cathode (negative) should be connected to the negative terminal of the power supply voltage. , Otherwise it will damage the capacitor.
Non-polar electrolytic capacitors are usually used in speaker frequency divider circuits, TV S correction circuits and single-phase motor starting circuits.
Electrolytic capacitors are widely used in household appliances and various electronic products, with a large capacity range, generally 1~33000μF, and a rated working voltage range of 6.3~700V. Its disadvantages are dielectric loss, large capacity error (the maximum allowable deviation is +100%, -20%), poor high temperature resistance, and prone to failure due to long storage time.
The polarity of the electrolytic capacitor. Pay attention to the "-" on the side of the electrolytic capacitor for negative and "+" for positive. If the positive and negative electrodes are not marked on the electrolytic capacitor, it can also be judged according to the length of its pins. It is the positive pole, and the short leg is the negative pole.
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