Capacitors Blog

Suntan Technology Company Limited
---All Kinds of Capacitors

We general offer 5-6 weeks lead time for our silver mica capacitors now.

With features high precision, high stability, high reliability and available in small values, silver mica capacitors are mostly used at high frequencies and in cases where low losses (high Q) and low capacitor change over the time is desired.

Capacitance Range: 1pF – 22,000pF
Tolerance: ±0.5pF, ±1%, ±2%, ±5%
Rated Voltage: DC 50V, 100V, 300V, 500V, 1000V
Operating Temperature: -55°C ~ +125°C
Withstanding Voltage: Rated voltage x 2 (V DC) within 1-5 seconds

More details or asking price of this capacitor, please check with our sales team sales@suntan.com.hk .

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

An overview or tutorial about the basics of the silver mica capacitor, its construction, properties and the uses of silver mica capacitors particularly in RF circuits.

Silver mica capacitors have been widely used as high performance capacitors over the years. Although silver mica capacitors are not as widely used, these days, nevertheless they are still available and used in a variety of applications where their particular properties are needed.
 
Silver mica capacitors are able to provide very high levels of accuracy, stability and low loss. As a result silver mica capacitors found many uses in radio frequency applications, particular for oscillator and filter circuits where their stability, accuracy and low loss (leading to high Q) were needed. Although not as widely used these days, they can still be obtained and are used where stability of value is of the utmost importance and where low loss is required. 
 
Two main reason for the decline in the use of silver mica capacitors is their size, resulting from the materials used and their construction. The cost of silver mica capacitors is higher than many other types that can often be used these days.
 
Silver mica capacitor properties

The reason for the continued use of silver mica capacitors is the fact that they can offer very high levels of performance, better in many areas than any other type of capacitor. However in many applications, other more modern technologies provide levels of performance that meets the needs for that particular requirement.
 
The particular properties of the silver mica capacitor are summarised below:
 
•High accuracy:   Silver mica capacitors can be obtained with tolerance figures of +/- 1%. This is much better than virtually every other form of capacitor available today. 
•Temperature co-efficient:   The temperature co-efficient of silver mica capacitors is much better than most other types of capacitor. The temperature coefficient is positive and is normally in the region 35 to 75 ppm / C, with +50 ppm / C being an average value 
•Value range:   Values for silver mica capacitors are normally in the range between a few picofarads up to two or possibly three thousand picofarads. 
•Low capacitance variation with voltage :   Silver mica capacitors exhibit very little voltage dependence. 
•High Q :   Silver mica capacitors have very high levels of Q and conversely small power factors. These are both almost independent of frequency. 
Although silver mica capacitors have a high tolerance and low temperature co-efficient they are known to jump in value on occasions.
 
Suntan SM mica capacitors are ideal for high requence and RF applications.SM is our tradmark about sliver mica capacitors,if you have any inquire about Sliver Mica capacitors,Pls contact our by website http://www.capacitors.hk/,   we can offer you all kinds of capacitors.

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

Suntan Silver Mica Capacitors with high reliability (SM tradmark)

Suntan Silver Mica Capacitors are available with values that range from 1–22,000 pF, voltages are in the range 50–1000V for standard dipped mica capacitors. Mica capacitors exhibit very little voltage dependence, have high Q or conversely small power factors that are quite independent of frequency. With all these advantage, our mica capacitors are ideal for high requence and RF applications.

Mica Capacitors Specifications

Brand SM
 
Capacitance range: 1pf – 22,000pf 
Tolerance: ±0.5pf, ±1%, ±2%, ±5% ~ 20% 
Rated voltage: dc 50v, 100v, 300v, 500v 
Operating temperature: -55°c ~ 125°c 
Withstanding voltage: rated voltage x 2 (vdc) within 1-5 seconds

Silver Mica Capacitors Knowledge

Silver mica capacitors are high precision high stability high reliability capacitors. They are available in small values, and are mostly used at high frequencies.

Mica capacitors, which are now obsolete, were in use in the early 20th century. They consisted of sheets of mica and copper foil sandwiched together and clamped.

Silver mica capacitors, also known as silvered mica capacitors, obsoleted mica capacitors. Instead of being clamped with foils these use sheets of mica coated on both sides with deposited metal. The assembly is dipped in epoxy. The advantages are:

• Greater stability, since there are no capacitive airgaps that can change dimension
• Airtight enclosure removes the risk of oxidation or corrosion of plates or connections
• Greater value per volume
• There are no airgaps between plates and mica
• The conducting surfaces can be thinner
• No clamping mechanism is needed

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

Suntan Silver mica (SM) capacitors are high precision, stability and reliability capacitors. They are available in small values, and are mostly used at high frequencies.

Generally known as silver mica capacitors, these rendered clamped mica capacitors obsolete. Instead of being clamped with foils these are assembled from sheets of mica coated on both sides with deposited metal. The assembly is dipped in epoxy. The advantages are:

1.greater stability, since there are no capacitive airgaps that can change dimension

2.airtight enclosure removes the risk of oxidation or corrosion of plates or connections

3.greater capacitance per volume, since

4.there are no airgaps between plates and mica,

5.the conducting surfaces can be thinner.

6.no clamping mechanism is needed

Suntan is a manufacturer of Mica Capacitors. Please refer to below product image of Mica Capacitors.For more details,please feel free to contact us.

Natural mica has to be carefully selected because some samples do contain impurities including, iron, sodium, ferric oxide, and lithium. This introduces some variability into any mica that might be used for capacitor manufacture and therefore it must be carefully inspected and classified. This is one of the reasons why silver mica capacitors are more expensive than other types which have less manual intervention.

Mica is chemically very stable and chemically inert. Mica does not react with oil, water, many acids alkalis, and solvents. As a result of this, ageing does not occur to any major degree, and the variations of water vapour in the atmosphere do not cause undue variations in the overall capacitor performance.

Although more costly than other dielectrics, mica is an ideal form of dielectric for very high performance capacitors such as silver mica capacitors.

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.

For meeting more and more customer's requirement on the urgent delivery, recently Suntan made an important decision that we will keep stock for some series, starting from tantalum capacitor which is always with long lead time, as well as hot offer TS08S X2 capacitors.

From the year of 2010, with the order increased sharply, our production lines are always overload and the delivery schedule is longer than former accordingly. Our management realized the importance and emergency of the availability of stocks, and decided to keep stock for some common series. The lead time of tantalum capacitor are extremely long, and the current requirement from the market for our TS08S X2 capacitor is fairly well, as a result we chose these 2 series as a starting. If you need these 2 series, just feel free to check with Suntan professional sales if any stock available or not. With the support from customers, we believe our stock could cover a wider range of series in the near future!

Shortcut to specs:
Tantalum capacitor - radial ---> http://www.suntan.com.hk/pdf/Tantalum-Capacitors/TS19.pdf
Tantalum capacitor - SMD ---> http://www.suntan.com.hk/pdf/Tantalum-Capacitors/TS20.pdf
X2 capacitor ---> http://www.suntan.com.hk/pdf/Plastic-Film-Capacitors/TS08S.pdf

These capacitors use Mica for the dielectric. Mica capacitors have good stability because their temperature coefficient is small. Because their frequency characteristic is excellent, they are used for resonance circuits, and high frequency filters. Also, they have good insulation, and so can be utilized in high voltage circuits. It was often used for vacuum tube style radio transmitters, etc.
Mica capacitors do not have high values of capacitance, and they can be relatively expensive.

Suntan Dipped Mica Capacitors are designed to meet the exacting physical, electrical and environmental requirements of the MIL-C-5 and RS-153 specifications.

It is well known that natural mica is extremely stable against heat. Silvered mica is made by printing electrodes on mica film with special silver paste. The silvered films are stacked to the desired value interleaved with metal foils for contact. Then the terminals are clamped on to the element. (The terminals are copper clad steel wires finished with a solider coating for good solder ability). The clamped unit is either dipped under vacuum in epoxy resin and coated with epoxy powder conformably or dipped in phenolic resin and vacuum impregnated with liquid epoxy resin. The envelope thus formed gives high moisture and heat resistance to the unit. This design ensures high reliability and stability.

Careful selection of raw materials and constant monitoring of all equipment and processes provides an overall uniform level of quality consistent with the stringent requirements of today's most sophisticated electronic equipment.