Yes if you are using a capacitor that has a DC voltage rating you can use a capacitor that has a higher rating without it being a problem however when the voltage is increased the size may also increase and that cause create a problem in where the capacitor is being placed in the application. You will need to check the size of both voltage ratings before switching to the higher voltage.

The most common ranges are:

-40° / +85°C

-55° / +105°C

-25° / +125° C

The additional leads are for physical stability in mounting the capacitor. It is used to ensure correct insertion. It should have no electrical connection.

Yes it indicates how long the capacitor with work at maximum efficiency when used at the maximum ambient temperature temperate rating. If the temperature is decreased the lifetime will be extended.

No you don’t. If your capacitor has more than 2 pins, you don’t have to use the other pins. They are only for mounting stability purpose. For any reason you may have, you can bend, remove all other terminals except positive and negative ones.

Some of the most common applications for snap-in capacitors to be used are:

audio-visual equipment

computers

domestic appliances

frequency converters

switch mode power supplies

welding machines

The ability to get a capacitor that can work in high voltage applications such as 400V, 450V and 500V in a compact size is just one of the reasons that this style is popular in these applications. The high reliability and low ESR ratings are also characteristics that make this style the right choice for many design engineers.

Aluminum electrolytic capacitor is the shortest life parts in power supplies. Other parts, like resin, have also their life, but they are 20 - 30 or over years. So the life on electric devices generally are not problems.

Aluminum electrolytic capacitor is the most important parts in terms of reliabilty, and expected lifetime of power supplies can be estimated by calculating the estimation of expected lifetime of aluminum electrolytic capacitor.

Expected lifetime of aluminum electrolytic capacitor is determined by amount of excess electorlyte, speed of electrolyte evaporating through sealed rubber and temperature that determines the evaporating speed.

The relationship between ambient temperature and capacitor life has been confirmed to follow ARRHENIUS' equation:

Expected lifetime of Electrolytic Capacitor: L = Lo x 2 (T1-T2) / 10

Lo: Lifetime Under Maximum Rated Operating Temperature

T1: Allowable Maximum Temperature

T2: Capacitor Temperature on operation

Life expectancy is determined by a coefficient depending on temperature, based on Lo.

Expected lifetime of aluminum electrolytic capacitor is defined by the reduction of capacitance less than the allowable value, tanδ increase or leakage current increase.

Aluminum electrolytic capacitor is used for input/output smoothing circuit, auxiliary power supplies circuit or phase compasation circuit, and the influence of the degradation of aluminum electrolytic capacitor is different.

Table 1 shows the influence of aluminum electrolytic capacitor lifetime by each circuit.

Since expected lifetime of alunimum electrolytic capacitor depends on environment (ambient temperature), power supply should be used well-ventilated place.