Membrane capacitors are widely used in the cross-linking of analog signals, the bypass of power noise (reverse cross-linking), etc. The film capacitor is a capacitor with metal foil as the electrode, and it is wound with a plastic film such as polyethylene, polypropylene, polystyrene or polycarbonate, etc. from both ends and wound into a cylindrical structure. According to the type of plastic film, they are also called polyethylene capacitors (also called Mylar capacitors), polypropylene capacitors (also called PP capacitors), polystyrene capacitors (also called PS capacitors) and polycarbonate capacitors.
The film capacitor has many excellent characteristics, so it is a capacitor with excellent performance. Its main equivalences are as follows: no polarity, high insulation resistance, excellent frequency characteristics (wide frequency response), and low dielectric loss. Based on the above advantages, film capacitors are widely used in analog circuits. Especially in the part where the signal is connected, capacitors with good frequency characteristics and extremely low dielectric loss must be used to ensure that the signal is transmitted without too much distortion. Among all plastic film capacitors, the characteristics of polypropylene (PP) capacitors and polystyrene (PS) capacitors are the most significant. Of course, the prices of these two capacitors are relatively high. However, in recent years, in order to improve the sound quality of audio equipment, the parts materials used have become more and more advanced, and the price is not the most important consideration, so in recent years, the frequency and number of PP capacitors and PS capacitors used in audio equipment have also increased. The higher.
The general method of making film capacitors is to make metal foils such as aluminum as electrodes and plastic films overlap and then wind them together. However, there is another manufacturing method for film capacitors, called Metallized Film. Its manufacturing method is to vacuum-deposit a thin layer of metal on the plastic film as an electrode. In this way, the thickness of the electrode foil can be omitted, and the volume per unit capacity of the capacitor can be reduced. Therefore, it is easier to make a thin film capacitor into a capacitor with a large capacity. For example, the common MKP Capacitor is the name of Metalized Polypropylene Film Capacitor, while MKT is the name of Metalized Polyester Capacitor.
The films used for metallized film capacitors include polyethylene, polypropylene, polycarbonate, etc. In addition to the wound type, there are also laminated types. The capacitor of this type of metallized film has a so-called self-healing effect (Self Healing AcTIon), that is, when it is assumed that a small part of the electrode is short-circuited due to the weak electrical interface, the electrode metal around the short-circuited part is caused. The electrostatic energy or short-circuit current carried by the capacitor at that time will cause a larger area of melting and evaporation to restore the insulation and restore the capacitor to the role of the capacitor again.
Now we introduce several fine film capacitors in the audio circle:
The film capacitors used in WIMA capacitors in audio equipment are the oldest and most well-known, and the first to introduce the German WIMA container. In the early years when the boom of motorcycles in Guangzhou was in full swing, WIMA could be the preferred premium product. Of course, many of the WIMA capacitors were from old products, so the price was relatively easy to accept. Although various imported and domestic brands of advanced film capacitors have become dazzling, WIMA should still be the most well-known brand. The most famous capacitor of WIMA is the PP capacitor with the number MKP-10.
ERO capacitors Another ERO capacitors that are also German brands are also very old. The most common ERO capacitors are green and some are blue. When assembled with WIMA on the circuit board at the same time, they are in good harmony. ERO is a brand of film capacitors, and ROE is another brand of advanced electrolytic capacitors. The two have the same English letters, but the order is different, and readers should not be confused.
Siemens capacitors are also German brands, but not much used in audio products are Siemens capacitors. This brand of soap electrolytic capacitors and film capacitors is happily adopted by the German HI-END brand MBL, and its performance is extremely excellent, so The strength does not allow small tattoos.
Philips Capacitors Philips is a very large enterprise group. The products it manufactures are countless. From the most popular household appliances to the most advanced space technology, it has a wide range of levels. Of course, the production of capacitors will not be missed. . The appearance of its capacitor is a light aqua blue, which can often be found in audio equipment recently.
Rifa Capacitor Rifa is a premium capacitor of the Swedish brand. The common PP capacitors are blue. The specifications and sound performance are very good, but the price is also very expensive. Therefore, few audio manufacturers use it, but I just point out The three famous audio companies using this brand, you can probably understand its strength. What about the three? Gryphon of Denmark, Mark Leivenson and Cello of the United States, which are the best audio agents.
Wonder capacitors are best known for their use of Counterpoint machines, and Audio Research also uses it. The appearance is a white cylindrical shape with a green sealant.
Relcap capacitors Relcap capacitors are best known for the use of Audio Research and have a pale yellow oval cylindrical shape.
Solen capacitors Solen capacitors in France have also been rapidly red in recent years. Its appearance is cylindrical, with a black skin, and both ends have brick red and gray. So far, it is the only well-known manufacturer that produces large-capacity MKP capacitors (up to 200F). Therefore, Solen capacitors are widely used in high-end speaker crossovers. Infinity speakers (including IRS-V's mid-range treble column), France's JM Lab speakers (Qingjian's ALCOR and UTOPIA are more attentive on the speaker backplate, with transparent glass glue SHOW to produce a specially customized super large Solen Capacitors are used to show that their materials are extraordinary.) In addition, they are used in many well-known manufacturers' crystal or tube machine circuits.
MIT capacitors Historically, MIT capacitors are the youngest advanced capacitors in history. They have only appeared in the market for three or more years. The topic of the circle. The reason is that its structure is special. The MIT capacitor is a composite capacitor (MulTI cap), which means that a capacitor is actually composed of multiple capacitors in parallel. What are the advantages of doing so? The equivalent series resistance and equivalent series inductance of the capacitor can be reduced again, making the MIT capacitor closer to the ideal capacitor, so all the technical specifications and characteristics that should be included are also excellent!
Of course, there is a price to pay for doing this. The price of MIT capacitors is expensive enough to deter manufacturers or individuals who want to use it. This is also the second noticeable aspect of it. In addition, its volume is relatively large in terms of the same capacity. On circuits that pay attention to the mounting density of parts, the convenience of application will be limited. Its appearance is a white elliptical column, the lead is very thick, the sealant is black, and it has two types of metal foil and metalized film.
