Electrolytic capacitors and ceramic capacitors are not interchangeable in general applications. I would like to remind individuals to pay attention to safety. The two capacitor shapes shown in the figure are absolutely not interchangeable! Pay attention! Do not operate rashly. In case someone gets hurt!
Electrolytic capacitors usually use metal foil (aluminum/tantalum) as the positive electrode, and the insulating oxide layer of metal foil (aluminum oxide/tantalum pentoxide) as the dielectric. Electrolytic capacitors can be divided into aluminum electrolytic capacitors and tantalum electrolytic capacitors according to the difference of their positive electrodes. The negative electrode of aluminum electrolytic capacitor is composed of thin paper/film or electrolyte polymer soaked in electrolyte liquid (liquid electrolyte); Manganese dioxide is usually used as the negative electrode of tantalum electrolytic capacitor. Electrolyte is the negative electrode, so electrolytic capacitor is named.
Polar electrolytic capacitors usually play the roles of power supply filtering, decoupling, signal coupling and time constant setting in power supply circuits or intermediate frequency and low frequency circuits. It cannot be used in AC power supply circuit. When it is used as a filter capacitor in DC power supply circuit, its anode (positive pole) should be connected with the positive terminal of power supply voltage, and its cathode (negative pole) should be connected with the negative terminal of power supply voltage. Otherwise, it will damage the capacitor and even explode, endangering personal safety. Therefore, we should pay special attention to safety when facing polar electrolytic capacitors, and we should not operate rashly. Pay attention to the polarity of the electrolytic capacitor, and observe that "-"is the negative pole and "+"is the positive pole on the side of the electrolytic capacitor. If the positive and negative poles are not marked on the electrolytic capacitor, it can also be judged according to the length of its pins, and the long pin is the positive pole and the short pin is the negative pole. There are strict regulations on the actual operation in the factory.
Non-polar electrolytic capacitor is usually used in speaker frequency divider circuit, TV S correction circuit and starting circuit of single-phase motor.
Ceramic capacitor is the general name of capacitor with ceramic material as medium. There are many kinds of them, and their external dimensions vary greatly. It is a nonpolar capacitor. According to the use voltage, it can be divided into high voltage, medium voltage and low voltage ceramic capacitors According to the temperature coefficient, different dielectric constants can be divided into negative temperature coefficient, positive temperature coefficient, zero temperature coefficient, high dielectric constant and low dielectric constant. Widely used in electronic circuits. The ceramic materials used in ceramic capacitors are made of oxides or other compounds, and then baked at a high temperature near the melting temperature. Ceramic is a complex polycrystalline and multiphase system, which is generally composed of crystalline phase, glass phase, gas phase and phase boundary. The characteristics, composition, relative content and distribution of these phases determine the basic properties of the whole ceramic.
Barium titanate-titanium oxide, a capacitor ceramic with high dielectric constant, is extruded into a round tube, disc or disc as a medium, and silver is plated on the ceramic as an electrode by sintering infiltration. There are two kinds of porcelain media: high frequency porcelain media and low frequency porcelain media. High-frequency capacitors with small positive capacitance temperature coefficient are used in high-stability oscillation circuits as loop capacitors and pad capacitors. Low-frequency ceramic capacitors are limited to bypass or DC isolation in circuits with low working frequency, or where stability and loss are not high (including high frequency). Such capacitors are not suitable for use in pulse circuits because they are easily broken down by pulse voltage.
