Capacitors Blog

Trimming Potentiometers is used by more and more products, its application including satellite receivers, modems, LCD displays, set-top boxes, and meters and instruments, as well as entertainment devices, such as cameras, and MP3 players.

Below is Suntan Trimming Potentiometers - TSR-3318 characteristics.

Suntan Technology Company Limited will attend Electronic Americas 2011 in Sao Paulo, Brazil from March 28th to April 1st, 2011

• Fair name: Electronic Americas 2011
• Add.: Sao Paulo, Brazil
• Date: March 28th to April 1st, 2011
• Booth No.: N₁50

On this exhibition, all products will be presented, like metalized polyester/ polypropylene film capacitor including X2 capacitor, MLCC and high voltage ceramic capacitor, aluminum electrolytic capacitor, trimming potentiometer, varistor and rectifier diode.

Welcome to visit our booth to establish or expand our business!

Natural mica contains many other materials including, iron, sodium, ferric oxide, and lithium. Because of the variability in composition of natural mica, mica destined for use in capacitors must be carefully inspected and classified, which adds to the manufacturing cost. All varieties of mica are chemically very stable and inert. Mica does not react with oil, water, most acids, (the exceptions are hydro-fluoric and sulfuric acid) alkalis, and solvents.

Mica’s thermal, electrical, and chemical properties make for excellent capacitors. Capacitance change with temperature range from ± 500 ppm/°C to 50 ppm/°C, depending on the construction technique. Mica capacitors exhibit very little voltage dependence, with dC/dV less than 0.1%. Mica capacitors have high Q or conversely small power factors (range 0.0001–0.0004) that are quite independent of frequency. This, combined with low inductance designs, result in capacitors that are ideal for high frequency and RF applications. Specification sheets of mica capacitors commonly show parameters plotted into the gigahertz range.

There are many types of mica, but only six or so are common rock-forming minerals. Mica capacitors are normally made from muscovite mica, or potassium aluminum silicate, KAl₂Si₃O₁₀(OH)₂ . It is thermally stable up to 500°C, and has a high dielectric strength. Phlogopite mica, or potassium magnesium silicate, KMg₃Si₃AlO₁₀(OH)₂ , is softer than muscovite mica and has less desirable electrical characteristics, but it may be used up to 900°C. Mica deposits are found in Madagascar, Central Africa, South America, and India. India is probably the biggest supplier of mica.

Mica, a mineral, is one of the oldest dielectric materials used in capacitor construction. There are several kinds of mica, with differing properties, but mica is in general very stable electrically, mechanically, and chemically. It has a dielectric constant in the range 5–7. Mica has the interesting property that its crystalline structure is asymmetrical. The binding forces in one plane are quite strong, while the binding forces along the perpendicular plane are very weak. Because of this, it has a distinct layered structure, and it is possible to split or cleave mica into very thin, optically flat, sheets. For capacitors, mica sheets in the range 0.025–0.125 mm or even thinner are used.

Previous blog we have talk the simplest ceramic capacitor consists of a square or circular shaped ceramic with electrodes attached.

Manufacturing starts with finely powdered base ceramic material that are pressed into dies and fired at high temperatures. Individual capacitors may be cut from large sheets of ceramic material. The capacitor electrodes (i.e. the plates) are attached by screen printing a mixture of silver, finely powdered glass, and a binder on both sides of the disk, and firing the ceramic element again. This evaporates the binder, and the melted glass binds the silver to the ceramic surface. Next, hairpin wires are clipped onto the capacitor and it is dipped in solder. Once cooled the capacitor is dipped into paint, marked, and the lower ends of the hairpin cut off. Clearly the whole process lends itself to automation, and dipped ceramic capacitors are very inexpensive. Capacitor characteristics depend on the type of ceramic used.



Dipped ceramic capacitor construction. (a) Capacitor after electrode and hairpin attachment. (b) Capacitor after dipping and marking.

http://www.suntan.com.hk/Ceramic-Capacitors/

Suntan Technology Company Limited
----All Kinds of Capacitors

Dipped Ceramic Capacitors. The simplest ceramic capacitor consists of a square or circular shaped ceramic with electrodes attached (see figure). The capacitance is given by 

where A is the area of the two plates,  is the dielectric permittivity of vacuum, Kd is the dielectric's dielectric constant and d is the distance between the two plates.http://www.capacitors.hk/Ceramic-Capacitors/

Suntan Technology Company Limited
----All Kinds of Capacitors

MLC capacitors are marvels of modern material science. Manufacturing MLC capacitors is considerably more complicated than manufacturing dipped ceramic capacitors. First, the base ceramic material is mixed with a binder and fashioned into thin sheets. Electrodes are painted onto one side of the sheets using a paint that consists of a liquid binder with fine metal particles in suspension. The metals that are used include gold, palladium, platinum, and silver alloys. The reason for using these metals is that when the base ceramic is fired, oxygen is required for the ceramic proper to form. If one uses a metal such as iron, for example, it would oxidize completely during the firing process.Precious metals do not have this problem, but is a major cost component of monolithic ceramic capacitors. However, recently some manufacturers have reported using nickel and copper for the electrodes. This promises to reduce the cost of the raw materials, but at the expense of more elaborate manufacturing processes.

Once the ink is dry, the sheets are stacked on top of each other. The painted electrodes are arranged so that alternate electrodes exit from opposite ends. The top and bottom most layers do not have painted electrodes. The laminated layers are then compressed and fired, which sinters them into one monolithic structure.

Next, the ends are terminated, often using silver. For leaded capacitors, wires are attached, and finally the capacitor is encapsulated in plastic and marked. In the case of chip capacitors, the silver end terminations are covered with tin to aid soldering. The whole capacitor may be covered with lacquer.

Suntan Technology Company Limited
---All Kinds of Capacitors

Aluminum electrolytic capacitors are comprised of anode and cathode plates separated by an absorbent spacer. As shown in Figure below, metal tabs are attached to the anode and cathode plates, and the assembly is wound into a cylindrical section. The tabs are welded to aluminum terminals installed in a header (top). The section-header assembly is immersed in a bath of hot capacitor electrolyte (significantly different from the formation process electrolyte). In what is called the impregnation process, a vacuum is applied to the electrolyte and sections, causing electrolyte to be drawn into the sections, thoroughly wetting the sections. The sections are placed in aluminum cans, and the headers are sealed to the cans. The capacitor units are slowly brought up to maximum rated voltage at maximum rated temperature during the aging process. The aging process grows oxide on areas on the anode foil which have an insufficient oxide barrier, such as slit edges and places which have been cracked during the winding operation. Inspections and tests occur at several stages of the production process.

For more details please check : http://www.capacitors.hk/Aluminum-Electrolytic-Capacitors/

A capacitor, also known as a condenser, is a component in electronic devices. It consists of a combination of three objects. First, a pair of objects called conductors conducts electricity. The conductors are separated by a dielectric, which is a substance that does not conduct electricity. Common dielectrics include substances such as paper, ceramic and plastic.

When an electric current exists between the two conductors, it creates an electric field in the dielectric, which can then store energy. The most effective capacitors employ conductors that are wide and flat, as well as being perfectly parallel, with a very small distance between them.

A run capacitor is a particular type of capacitor. A run capacitor uses the charge stored in the dielectric in order to boost the electrical current providing power to an electric motor. This type of capacitor is created to maintain a charge during constant use of the motor. These capacitors are often found in devices, such as heaters, that are continuously running.

One variety of run capacitor is often used in air conditioners. This type of run capacitor is called a dual run capacitor, and uses two run capacitors for two different functions. In an air conditioner, for example, one run capacitor is used to boost the fan motor, and another is used to boost the compressor motor.

Run capacitors typically are classified at 370 or 440 volts. It is necessary to ensure that the correct rating of run capacitor is installed in an engine. If a run capacitor with an incorrect voltage rating is installed in a motor that requires a capacitor for second-phase energy, it will throw off the magnetic field. An uneven magnetic field will cause the rotor to slow in the uneven spots, which increases energy noise, as well as power consumption, and can also cause performance problems and overheating issues.