Suntan Blog

The service life of an aluminum electrolytic capacitor for mid- to high-voltage filters is affected by the applied voltage. If the applied voltage is between 60% and 100% of the rated voltage, the estimated service can be extended by lowering the applied voltage below the rated voltage. However, if the applied voltage is less than 60% of the rated voltage or the capacitor is used in low-pressure (100 WV or less) applications, the impact of the applied voltage on the service life is negligible.

Therefore, service life is estimated assuming no impact from voltage. Continuous application of a voltage over the rated voltage rapidly increases leakage current in a capacitor. This may increase internal pressure due to generation of gases, resulting in activation of the safety vent in a short time and/or formation of an internal short circuit. For this reason, the applied voltage must be maintained below the rated voltage during use.

Besides, it should be noted that the circuit design is such that the applied voltage will remain 80% or less of the rated voltage during use.

Where more than one capacitor connected in series is used, the applied voltages across the individual capacitors may become out of balance, resulting in the application of excessive voltage to them. To avoid this, either choose a rated voltage allowing for voltage imbalances, or connect a voltage divider(resistors) to the capacitors. Please be careful about charge/discharge.

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.

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.

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.

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.

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.

Very large capacitance to volume ratio, inexpensive, polarized. Primary applications are as smoothing and reservoir capacitors in power supplies.Our Suntan Aluminum Electrolytic Capacitors with features of Low ESR, Long life, Compact size.stable temperature(20~105°C). The rated Voltage Range from 2VDC to 16VDC, capacitance range from 10uF to 270uF.

Applications: Power supply for digital-signal processing circuits of a variety of digital equipment (flat panel displays, DVD recorders, automotive navigation systems, etc.)

If you want to know more information about Aluminum Electrolytic Capacitors,I suggest you visit  website which is normal ,as it can give you the real suggestion and  can meet your requirements .So go to www.suntan.com.hk and have a look ,maybe it will makes you surprised .Because our Aluminum Electrolytic Capacitors has high quality and sells very well  ，Aluminum Electrolytic Capacitors has many diferent types ,all these types have a good reputation.

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.

Suntan Technology Company Limited
---All kinds of Capacitors

Aluminum is used for the electrodes by using a thin oxidization membrane.

Large values of capacitance can be obtained in comparison with the size of the capacitor, because the dielectric used is very thin.

The most important characteristic of electrolytic capacitors is that they have polarity. They have a positive and a negative electrode.

[Polarised] This means that it is very important which way round they are connected. If the capacitor is subjected to voltage exceeding its working voltage, or if it is connected with incorrect polarity, it may burst. It is extremely dangerous, because it can quite literally explode. Make absolutely no mistakes.

Generally, in the circuit diagram, the positive side is indicated by a "+" (plus) symbol.

Electrolytic capacitors range in value from about 1µF to thousands of µF. Mainly this type of capacitor is used as a ripple filter in a power supply circuit, or as a filter to bypass low frequency signals, etc. Because this type of capacitor is comparatively similar to the nature of a coil in construction, it isn't possible to use for high-frequency circuits. (It is said that the frequency characteristic is bad.)

The photograph on the left is an example of the different values of electrolytic capacitors in which the capacitance and voltage differ.

From the left to right:

• 1µF (50V) [diameter 5 mm, high 12 mm]
• 47µF (16V) [diameter 6 mm, high 5 mm]
• 100µF (25V) [diameter 5 mm, high 11 mm]
• 220µF (25V) [diameter 8 mm, high 12 mm]
• 1000µF (50V) [diameter 18 mm, high 40 mm]

The size of the capacitor sometimes depends on the manufacturer. So the sizes shown here on this page are just examples.

In the photograph to the right, the mark indicating the negative lead of the component can be seen.

You need to pay attention to the polarity indication so as not to make a mistake when you assemble the circuit.