Capacitors Blog

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

A vacuum variable capacitor uses a high vacuum as the dielectric instead of air or other insulating material. This allows for a higher voltage rating and/or capacitance value using a smaller total volume. In addition to the higher voltage rating a vacuum dielectric greatly reduces the chance of arcing between the plates. There are several different designs in vacuum variables, the most common geometry of the capacitor plates is usually inter-meshed concentric cylinders. The meshed cylinders are contained within a glass or ceramic vacuum envelope, similar to an electron tube. A metal bellows is used to maintain a vacuum seal while allowing positional control for the moving parts of the capacitor.

Common Applications

Vacuum variable capacitors are commonly used in high voltage applications 5000 volts(5kV) and above. They are used in equipment such as high powered broadcast transmitters, Amateur radio RF Amplifiers and large Antenna tuners.

Other Variations

A fixed value vacuum capacitor. Other variations of vacuum capacitors include fixed value capacitors. Fixed value capacitors are designed very much like the variable versions with the exception of an adjustment mechanism.

Comparison

When compared to other variable capacitors vacuum variables tend to be more precise and more stable. This is due to the vacuum itself. Because of the sealed chamber the dielectric constant remains the same over a wider range of operating conditions. With air Variable capacitors the air moving around the plates may change the value slightly; often it’s not much but in some applications is enough to cause undesirable effects. Another common problem with air variables is dust and insects. Dust collected on the plates or a curious insect can raise havoc. A wandering spider is bound to make fireworks with the open frame design used on most air variable capacitors.

Vacuum variable capacitors are generally more expensive than Air Variable Capacitors this is primarily due to their design and the materials used. Although most use copper and glass some may use other materials such as ceramics and metals such as gold and silver. Vacuum variables also vary in adjustment mechanisms which range from course to fine.

Suntan is a Hong Kong based manufacturer of Ceramic Capacitors. Including High Voltage Ceramic Capacitors, Multilayer Ceramic Capacitors, Ceramic Disc Capacitor, Mini Type Ceramic Capacitors etc.

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

Suntan pictures of Capacitors. Notice that all these capacitors have two wires coming out of them, one attached to each plate.

Suntan is well established and specializes in service and quality with an extensive export and import network. We provide quick turn around for our customers all over the world. Almost 30 years experience with all types of passive components using good materials, state of the art equipment and technology and ongoing QC coupled with extensive R & D assure our customers of the best quality and on time delivery.

Suntan offer many kinds of capacitors. Don’t hesitate to send us inquire to sales@suntan.com.hk .We will show you good quality and best price.

Mica Capacitor Specifications：

Capacitance Range : 1pf – 22,000pf
Tolerance : ±0.5pf, ±1%, ±2%, ±5% ~ 20%
Rated Voltage : dc 50v, 100v, 300v, 500v
Operating Temperature: -55℃ ~ 125℃
Withstanding Voltage: rated voltage x 2 (vdc) within 1-5 seconds

Link：http://www.suntan.com.hk/pdf/Mica-Capacitors/TS23.pdf
Contact Email：info@capacitors.com.hk

Basic Information:

Atomic Number: 13 
Atomic Mass: 26.981539 amu 
Melting Point: 660.37℃ (933.52 K, 1220.666 °F) 
Boiling Point: 2467.0℃ (2740.15 K, 4472.6 °F) 
Number of Protons/Electrons: 13 
Number of Neutrons: 14 
Classification: Other Metals 
Crystal Structure: Cubic 
Density @ 293 K: 2.702 g/cm3 
Color: Silver 
British Spelling: Aluminium 
IUPAC Spelling: Aluminium

Atomic Structure:

Number of Energy Levels: 3
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 3

Isotopes:

Facts:

Date of Discovery: 1825
Discoverer: Hans Christian Oersted
Name Origin: From the Latin word alumen
Uses: airplanes, soda cans
Obtained From: bauxite

If using an iron for manual soldering (for prototyping or repairs, for example) use an appropriate size and temperature so that the high temperature exposure of the trimmer is less than 3 seconds.
We strongly recommend the use of water soluble fluxes for soldering, followed by cleaning in water containing detergents, and then a clear water rinse.

Some operations still use Freon or similar fluorinated or chlorinated hydrocarbon solvents. These solvents have a tendency to remove the lubricant, which in turn makes for bumpy adjustment, and will degrade the tuning torque, adjustment life, and other mechanical specifications.

In general, the minimum exposure to cleaning solutions is recommended. The gentlest would be the detergent and water rinses at fairly low temperatures. When chlorinated or fluorinated hydrocarbons are used, the boards should never be plunged into the solvent solution, but rather maintained in the vapor area of the defluxing equipment, and for the minimum possible time. Most desirable would be to clean only the bottom of the printed circuit board, as with board scrubbers.

The unsealed GKG models are usually specified for consumer applications where cleaning after soldering is normally not required. Should cleaning be required, the method to use would be to clean the bottom of the board, as with board scrubbers. If a solvent is used when cleaning the GKG series, sealed versions should be specified to prevent the solvent from being trapped in the housing and degrading performance.

Other precautions for using ceramic trimmer capacitors include:

Beware of excessive handling with bare hands as, "finger oil" and dirt can bring down Q and insulation resistance values.

Terminals should not be cut or reformed, as this could cause deformation of the spring or breaking of the rotor.

Suntan Technology Company Limited
---All Kinds of Capacitors

Suntan hot offer Mylar capacitors, below shows you the features.

Good reputation in use with consumer & industrial electronics. 
Optimum for automatic insertion due to their small size and light weight.
Coated with epoxy resin for superior heat resistance, humidity resistance and solvent resistance.

Also Suntan is a manufacturer of Plastic Film Capacitors, Trimming Potentiometers, Capacitors, Varistors and so on. The more details you can look through the website: http://www.suntan.com.hk/
http://www.suntan.com.hk/Plastic-Film-Capacitors/Mylar-Capacitor.html

We are welcome to received your inquire and solve you problem.

A mylar capacitor uses mylar, which is a type of high temperature polyester film, as its dielectric. It is typically very stable and able to operate over a wide range of temperatures, usually up to 125 degrees Celsius. As such therefore this type is a common choice for instrumentation equipment, also high quality audio and communications equipment. There may be various shapes, sizes and styles of construction but possibly the longest lived and most recognisable style is the green or brown resin-dipped radial type, which coupled with a small physical size makes it readily suitable for circuit boards.

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

Potentiometers can be obtained with either linear or logarithmic laws (or "tapers").

Linear taper potentiometer

A linear taper potentiometer (Below Figure)has a resistive element of constant cross-section, resulting in a device where the resistance between the contact (wiper) and one end terminal is proportional to the distance between them. Linear taper describes the electrical characteristic of the device, not the geometry of the resistive element. Linear taper potentiometers are used when an approximately proportional relation is desired between shaft rotation and the division ratio of the potentiometer; for example, controls used for adjusting the centering of (an analog) cathode-ray oscilloscope.

Logarithmic potentiometer

A logarithmic taper potentiometer (Below Figure)has a resistive element that either 'tapers' in from one end to the other, or is made from a material whose resistively varies from one end to the other. This results in a device where output voltage is a logarithmic (or inverse logarithmic depending on type) function of the mechanical angle of the pot.

Logarithmic taper potentiometers are often used in connection with audio amplifiers. The most common use of a pot in audio is as a volume control. Since our hearing has a logarithmic response to sound pressure, it is important that the volume control should provide a smooth variation from soft to loud, such that a given change in position of the pot causes the same sensation of volume change at all levels.

In the early days, when an audio taper (logarithmic, or just log) was needed, the resistance element was indeed tapered, so that it provided a different resistively at different settings. By changing the physical taper, it was possible to make a pot provide the exact gradient of resistance needed. By definition, a linear pot has no taper as such (the resistance element is parallel sided), but the term has stuck, so we might as well get used to it.

The violet curve in Figure shows an antilog or reverse audio taper pot. These are quite uncommon, but used to be used for balance controls using a log/antilog dual section (commonly called dual gang) pot. It is shown on the graph mainly for its interest value, but they are generally an historical component now.

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

Trimming Potentiometers also come in many different shapes and sizes, with wattage ranging from 0.1W to 0.5W. Below shows several different trim pots, along with the symbol.

Resistance adjustments are made via a screwdriver. Exception is the trim pot on the lower right, which can be adjusted via a plastic shaft. Particularly fine adjusting can be achieved with the trim pot in the plastic rectangular casing (lower middle). Its slider is moved via a screw, so that several full turns is required to move the slider from one end to the other.

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

Trimmer Capacitor - 3mm 
Operating Temperature Range : -25℃ -- +85℃

Link: http://www.suntan.com.hk/pdf/Ceramic-Trimmer-Capacitors/TSC3.pdf
Pls contact me by email: sales@suntan.com.hk