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Capacitance can be decreased in a circuit by capacitors in series as shown in the following diagram:

We know that capacitance of a capacitor can be decreased by placing the plates further apart. Connecting two or more capacitors in series in effect increases the distance between the plates and thickness of the dielectric, thereby decreasing the amount of capacitance.

The following is the formula for calculating total capacitance in a circuit containing two capacitors in series:
                                                 
CT = (C1 x C2x C3) / (C1 + C2+ C3)

Aluminum electrolytic capacitors ('capacitors') may cause explosion, fire, or other serious hazard if used outside the specified operating conditions. Please familiarize yourself with the instructions below before using these capacitors.

1.Check the operating and installation environment and use the capacitor within the range of the rated performance specified in the catalog or specifications.

2.Maintain operating temperature and ripple current within the specified ranges. Base your choice of capacitors on the maximum load conditions. A capacitor will overheat under excessive current, potentially resulting in short circuit, fire, or other major failure.

3.A capacitor also generates the self heating. Please bear in mind that the capacitor heats up the interior of the equipment, and take appropriate precautions. Operate the unit under normal conditions and check the temperature of the area surrounding the capacitor.

4.The permissible ripple current declines with the rise in ambient temperature (the temperature of the capacitor's surroundings).Consider the permissible ripple current at the maximum predictable ambient temperature.

5.Electric characteristics change as frequencies change. Check frequency changes in order to choose the right capacitor. Special attention needs to be given to the self heating and short life time both low and high frequency, when equivalent series resistance and inductance change.

Gold capacitor 5.5V 1.0 F super capacitor, gold capacitor, ultra capacitor , Electric Double-layer capacitor ,EDLC ,Farad capacitor , super capacitor which have some performance : unlimited charge or discharge cycle ,Small-size, large capacity, excellent voltage holding. Wider temperature range from -25 to70 ,Low ESR ,high energy density. Which nominal capacity range is 0.1F-3000F.operating voltage range is from 2.5V to 5.5V. It used in many fields , Toys, Medical equipment, Bicycle Light, Flashlights, UPS, GPS storing power for Video,Audio,CMOS,RAM,VCR,scanner,Telephone,Computer,LED,Relay,Wireless ,Consumption Electronics, Buzzer

Concerning on TS12S-S (Electric Double Layer Capacitor - Stacked Coin (Small Capacitance)(under develop), miniature size, low leakage, safety and high reliability, the rated capacity is from 0.15F to 8.0F at 2.7~ 5.5V voltage. There are V & H type to be chosen.

A MOV inside a TVSS device does not provide equipment with complete power protection. In particular, MOV device provide no protection for the connected equipment from sustained over-voltages that may result in damage to that equipment as well as to the protector device.

A varistor provides no equipment protection from inrush current surges (during equipment startup), from over current (created by a short circuit), or from voltage sags (also known as a brownout). A varistor neither senses nor controls such events. Susceptibility of electronic equipment to these other power disturbances is defined by equipment design. Protection from these power disturbances is installed inside that equipment or is provided by other external devices such as an UPS, some voltage regulators and Surge Protectors with built in over voltage protection that make use of a voltage sensing circuit and a relay for disconnecting the AC input when voltage reaches a danger threshold.

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.

Mica capacitors are available with values that range from 1–4700 pF and even up to 1 μF, but they are generally thought of as low value capacitors. Rated voltages are in the range 100–1000 V for standard dipped mica capacitors. Rated voltages for RF transmitting capacitors are up to 10 kV. Given the excellent electrical performance of mica capacitors in general, manufacturers typically market them with close tolerances (1% or better).

Unlike capacitors that use a bulk dielectric made from an intrinsically insulating material, the dielectric in electrolytic capacitors depends on the formation and maintenance of a microscopic metal oxide layer. Compared to bulk dielectric capacitors, this very thin dielectric allows for much more capacitance in the same unit volume, but maintaining the integrity of the dielectric usually requires the steady application of the correct polarity of direct current else the oxide layer will break down and rupture, causing the capacitor to lose its ability to withstand applied voltage (although it can often be "reformed"). In addition, electrolytic capacitors generally use an internal wet chemistry and they will eventually fail if the water within the capacitor evaporates.

Electrolytic capacitance values are not as tightly-specified as with bulk dielectric capacitors. Especially with aluminum electrolytic, it is quite common to see an electrolytic capacitor specified as having a "guaranteed minimum value" and no upper bound on its value. For most purposes (such as power supply filtering and signal coupling), this type of specification is acceptable.

Simple capacitance scales on DMMs just measure the capacitance in uF and do not test for leakage, ESR (Equivalent Series Resistance), or breakdown voltage. If the measurement comes up within a reasonable percentage of the marked value (some capacitors have tolerances that may be as much as +100%/-20% or more), then in many cases, this is all you need to know. However, leakage and ESR frequently change on electrolytic as they age and dry out.

Many capacitance meters don't test anything else but are probably more accurate than a cheap DMM for this purpose. A meter of this type will not guarantee that your capacitor meets all specifications but if it tests bad - very low - the capacitor is bad. This assumes that the test was made with the capacitor removed (at least one lead from the circuit - otherwise other components in parallel can affect the readings.

To more completely characterize a capacitor, you need to test capacitance, leakage, ESR, and breakdown voltage. Other parameters like inductance aren't likely to change on you.

Smaller spark gaps are often used to protect sensitive electrical or electronic equipment from high voltage surges. In sophisticated versions of these devices (called gas tube arresters), a small spark gap breaks down during an abnormal voltage surge, safely shunting the surge to ground and thereby protecting the equipment. These devices are commonly used for telephone lines as they enter a building; the spark gaps help protect the building and internal telephone circuits from the effects of lightning strikes. Less sophisticated (and much less expensive) spark gaps are made using modified ceramic capacitors; in these devices, the spark gap is simply an air gap sawn between the two lead wires that connect the capacitor to the circuit. A voltage surge causes a spark which jumps from lead wire to lead wire across the gap left by the sawing process. These low-cost devices are often used to prevent damaging arcs between the elements of the electron gun(s) within a cathode ray tube (CRT).

Suntan ( www.suntan.com.hk ) has supply Spark Capacitors .The Spark Capacitors - TS21 features are: Spark gap capacitors are designed to provide a reliable discharge path for stray, transient over voltages and static voltage build-up. The construction of the spark gap enable the circuit designer to reduce cost by specifying lower voltage components with the assurance that over-voltage conditions will be prevented.

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

Electric Double Layered Capacitors , know as “Gold Capacitor”, offer the highest volumetric efficiency of all capacitor technologies. It is often compared to a secondary battery. Unlike batteries, the Gold Capacitor does not rely on a chemical reaction to produce electric current rather it is a storage cell that utilizes the absorption/release reaction of ions.

Compared to other capacitors and batteries,Gold Capacitors are very new. We have summarized the characteristics and reliability of Gold Capacitors in this manual. Suntan has developed the Gold Capacitor to meet your design needs. We hope you will find this manual informative and useful. Any requirements please visit www.suntan.com.hk.

The polypropylene is sometimes used when a higher tolerance is necessary than polyester capacitors offer. As the name implies, this capacitor uses a polypropylene film for the dielectric. One of the advantages of the capacitor is that there is very little change of capacitance with time and voltage applied. They are also used for low frequencies, with 100 kHz or so being the upper limit. They are generally only available as leaded electronics components.

Such as our polypropylene film capacitors , it has three features:

1. Comparatively small size saves space of print circuit board.

2. Temperature dependence indicates characteristic of negative.

3. Dissipation Factor is normally low and temperature dependence of capacitance is linear.