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

An electrolytic capacitor is a type of capacitor that uses an electrolyte (an ionic conducting liquid) as one of its plates to achieve a larger capacitance per unit volume than other types, but with performance disadvantages. All capacitors conduct alternating current (AC) and block direct current (DC) and can be used, amongst other applications, to couple circuit blocks allowing AC signals to be transferred while blocking DC power, to store energy, and to filter signals according to their frequency. Although most electrolytic capacitors are polarized; hence, they can only be operated with direct current (DC). The large capacitance of electrolytic capacitors makes them particularly suitable for passing or bypassing low-frequency signals and storing large amounts of energy. They are widely used in power supplies and for decoupling unwanted AC components from DC power connections.

Electronic capacitors are one of the most widely used electronic components. These electronic capacitors only allow alternating or changing signals to pass through them, and as a result they find applications in many different areas of electronic circuit design. Suntan supply a wide variety of types of capacitor including electrolytic, ceramic, tantalum, plastic, sliver mica, and many more. Each capacitor type is introduced in www.suntan.com.hk.

Two types of electrolytic capacitor are in common use: aluminum and tantalum. Tantalum capacitors have generally better performance, higher price, and are available only in a more restricted range of parameters. Solid polymer dielectric aluminum electrolytic capacitors have better characteristics than wet-electrolyte types—in particular lower and more stable ESR and longer life—at higher prices and more restricted values. 

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

One of the main application classes of aluminum electrolytic capacitors is input capacitors for power inverters.
The aluminum electrolytic capacitor provides a unique value in high energy storage and low device impedance. How you go about selecting the right capacitor or capacitors, however, is not a trivial matter.

Selecting the right capacitor for an application requires a knowledge of all aspects of the application environment, from mechanical to thermal to electrical. The goal of this paper is to assist you with selecting the right capacitor for the design at hand.

Capacitor ripple current waveform considerations. Inverters generally use an input capacitor between a ectified line input stage and a switched or resonant converter stage.

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

Suntan is a Hong Kong based manufacturer of Aluminum Electrolytic Capacitors, Including Snap-in type Electrolytic Capacitor, Screw type and LUG type Aluminum Electrolytic Capacitor, Axial & Radial Electrolytic Capacitor and SMD Aluminum Electrolytic Capacitor etc. Please refer to below product list of Aluminum Electrolytic Capacitors.

Aluminum Electrolytic Capacitors List

1. Axial Aluminum Electrolytic Capacitors
2. SMD Aluminum Electrolytic Capacitors
3. Radial Aluminum Electrolytic Capacitors
4. Snap-in type Aluminum Electrolytic Capacitors
5. Screw type Aluminum Electrolytic Capacitors
6. lug type Aluminum Electrolytic Capacitors
7. Polymer Solid Aluminum Electrolytic Capacitors
8. Technical-Note

Suntan Technology Company Limited
---All Kinds of Capacitors

Suntan aluminum Electrolytic capacitors store charge in a chemical paste called an electrolyte. They have large capacitance values, and are inexpensive and durable. Electronic designers typically use electrolytic capacitors to remove electrical noise from circuits. Since these capacitors are polarized, you must pay attention to the positive and negative leads or risk an explosion. When you use electrolytic aluminum capacitor, note that it has its capacitance and voltage values clearly printed on the body of the part. 

Electrolytic capacitors have capacitance ratings in the range of 10 to 200,000 microfarads. The voltage rating is the maximum voltage to which the capacitor should be subject. Maximum voltages for electrolytic generally range from 20 to 600 volts.

Suntan manufacture a wide range of Aluminum Electrolytic Capacitors, Including Snap-in type Electrolytic Capacitor, Screw type and LUG type Aluminum Electrolytic Capacitor, Axial & Radial Electrolytic Capacitor and SMD Aluminum Electrolytic Capacitor etc.

For more details, you can check on our website:www.suntan.com.hk.

The capacitance value of any capacitor is a measure of the amount of electric charge stored per unit of potential difference between the plates. The basic unit of capacitance is a farad; however, this unit has been too large for general use until the invention of the double-layer capacitor, so microfarad (μF, or less correctly uF), nanofarad (nF) and picofarad (pF) are more commonly used.

The capacitance of aluminum electrolytic capacitors tends to change over time, and they usually have a tolerance range of 20%. Some have asymmetric tolerances, typically −20% but with much larger positive tolerance as many circuits merely require a capacitance to be not less than a given value.Tantalum electrolytics can be produced to tighter tolerances and are more stable.

Suntan is a Hong Kong based manufacturer of Aluminum Electrolytic Capacitors, Including Snap-in type Electrolytic Capacitor, Screw type and LUG type Aluminum Electrolytic Capacitor, Axial & Radial Electrolytic Capacitor and SMD Aluminum Electrolytic Capacitor etc.

Electrolytic capacitors are polarised and they must be connected the correct way round, at least one of their leads will be marked + or -. They are not damaged by heat when soldering.

There are two designs of electrolytic capacitors; axial where the leads are attached to each end (220µF in picture) and radial where both leads are at the same end (10µF in picture). Radial capacitors tend to be a little smaller and they stand upright on the circuit board.

It is easy to find the value of electrolytic capacitors because they are clearly printed with their capacitance and voltage rating. The voltage rating can be quite low (6V for example) and it should always be checked when selecting an electrolytic capacitor. If the project parts list does not specify a voltage, choose a capacitor with a rating which is greater than the project's power supply voltage. 25V is a sensible minimum for most battery circuits.

1.Please make sure the application and mounting conditions to which the capacitor will be exposed  are within the conditions specified in the catalog or alternate product specification (Referred as to specification here after).

2.Operating temperature and applied ripple current shall be within the specification.

The capacitor shall not be used in an ambient temperature which exceeds the operating temperature specified in the specification.

Do not apply excessive current which exceeds the allowable ripple current.

3. Appropriate capacitors which comply with the life requirement of the products should be selected when designing the circuit.

4. Aluminum electrolytic capacitors are polarized. Make sure that no reverse voltage or AC voltage is applied to the capacitors.  Please use bi-polar capacitors for a circuit that can possibly see reversed polarity.

Note: Even bi-polar capacitors can not be used for AC voltage application.

When DC voltage is applied, leakage current flows through a capacitor. The leakage current of aluminum electrolytic capacitors is larger than other types of capacitors; furthermore, the leakage current changes according to the temperature, applied voltage and application time.  If considering an equivalent circuit, the leakage current can be thought as the current flows through a resistance, which is connected in parallel to a capacitor. Leakage current becomes the power loss when capacitors are charged and self-discharge source when capacitors are discharged; therefore, it increases with error for the theoretical formulas.

The time constant in charge becomes lager than theoretical value and time constant in discharge becomes smaller than theoretical value. It is important to confirm that the capacitor meets the necessary requirements within the operating temperature range of the equipment, when using an aluminum electrolytic capacitor in a timing circuit.

An aluminum electrolytic capacitor consists of cathode aluminum foil, capacitor paper (electrolytic paper), electrolyte, and an aluminum oxide film, which acts as the dielectric, formed on the anode foil surface.

A very thin oxide film formed by electrolytic oxidation (formation) offers superior dielectric constant and has rectifying properties.  When in contact with an electrolyte, the oxide film possesses an excellent forward direction insulation property.  Together with magnified effective surface area attained by etching the foil, a high capacitance yet small sized capacitor is available.

As previously mentioned, an aluminum electrolytic capacitor is constructed by using two strips of aluminum foil (anode and cathode) with paper interleaved.  This foil and paper are then wound into an element and impregnated with electrolyte. The construction of an aluminum electrolytic capacitor is illustrated in Fig below.

Aluminum electrolytic capacitors are made by layering the electrolytic paper between the anode and cathode foils, and then coiling the result. The process of preparing an electrode facing the etched anode foil surface is extremely difficult. Therefore, the opposing electrode is created by filling the structure with an electrolyte. Due to this process, the electrolyte essentially functions as the cathode. The basic functional requirements for the electrolyte are as follows:

(1) Chemically stable when it comes in contact with materials used in the anode, cathode, and electrolytic paper.
(2) Easily wets the surfaces of the electrode.
(3) Electrically conductive.
(4) Has the chemical ability to protect the anode oxide thin film and compensate for any weaknesses therein. 
(5) Low volatility even at high temperatures
(6) Long-term stability and characteristics that take into consideration such things as toxicity.