Capacitors

[krishtriram]

Dear All,

What are the various types of capacitors(based on construction eg:disc,polypropylene,tantalum) and what are their specific usage?

 

[Nostrafus]

Well, there are a bunch of different kinds, Disc capacitors are standards, they don't really have a specific polarity, they have a broad use, and are also cheap.

Tatalium capacitors are more for projects which generate a lot of heat, like a capacitor driven motor, or a portable generator.

Electrolytic also have a wide variety of uses, but have specific polarity, well not polarity, cathodes. The negative is the one usually marked, and they can also get up there in voltage/capacitance, the most I've seen is a 1000uF, 500v electrolytic, for heavy usage, such as air ionizers, and stun guns, or something that needs a lot of juice.

Also there are super capacitors, which can get close to 1 Farad, which is extremely lethal with the proper voltage behind it, these are normally used for generator type purposes, but need a heat sink, because they normally don't have the heat dissapation qualities as tatalium capacitors.

There are also mylar dipped capacitors, I can't remember exactly what they are used for, but if I remember correctly they are more heat stable and are great for precision timing. (Only thing I've ever actually seen one of these used in was a stungun, but then again I only look at broken stuff, not about to pop open my power supply on my computer while it's still working or anything like that)

Please correct any of these that are wrong, most of the stuff I work with are ceramic disc, and electrolytic.

Plus you can also choose from PCB type, and surface mount, although surface mount can run a little more, they take up less space because you don't have to worry about leads, or punching any holes, all you do is solder the sides to the copper, which you form a T on the copper lines to get a better surface connection where you are going to solder on surface mounts.

 

[pebe]

.....Tatalium capacitors are more for projects which generate a lot of heat, like a capacitor driven motor, or a portable generator.

Electrolytic also have a wide variety of uses, but have specific polarity, well not polarity, cathodes. The negative is the one usually marked, and they can also get up there in voltage/capacitance, the most I've seen is a 1000uF, 500v electrolytic, for heavy usage, such as air ionizers, and stun guns, or something that needs a lot of juice.

Also there are super capacitors, which can get close to 1 Farad, which is extremely lethal with the proper voltage behind it, these are normally used for generator type purposes, but need a heat sink, because they normally don't have the heat dissapation qualities as tatalium capacitors....

....Please correct any of these that are wrong, most of the stuff I work with are ceramic disc, and electrolytic.......

A correction is needed here. Tantalum capacitors are polarised to work in a circuit which contains a DC component in the same way electrolytics do. They don't produce heat. Indeed, most capacitors don't produce heat. Heat can only be produced by high ripple current in an electrolytic capacitor flowing through its inherent series resistance - and in tantalums this resistance is minimal.

For this reason capacitors don't require heat sinks.