Understanding capacitors markings???

[bear-hifi]

How can someone tell what material this capacitor is using? These types of caps do not have the markings like MKP and so on… Better yet how could a person tell if they are oil caps?


Thanks

Frank

 

[ferninando]

I'd say they are tantalum(sp?) as the dielectric. Dielectric types are not usually revealed on the extrnl of the cap. The way ythey LOOK is the givaway but you must be familiar with all the types out there and that comes withexperience working in the field with caps all the time. You could get a 'capacitor' reference book showing each type of cap and what it's made of. Try asking a mfr for something like that. Librarys would have books on electronics components, caps specifically.

 

[LDK180]

The military likes tantalums because of their reliability (I just learned that last night). The "M" in the number might be a clue that it is a military part, and in fact, a tantalum.

I'm not a capacitor expert but I do play one on TV.

 

[Bob E.]

Is there a polarity marking? I don't see one, so I'm going to go with some sort of plastic film cap. Are they glass-sealed on the ends? If so, they are probably high-quality mylar or other polyfilm caps, like the old Sprague Vitamin-Q or Cornell-Dublier types. Tantalum caps are a type of electrolytic cap (and the tantalum is the metal foil inside, not the dielectric) and would have a polarity marking. Tantalum caps are easy to distinguish from ordinary aluminum electrolytics by virtue of their weight...they are quite heavy compared to aluminum caps, and they usually are not over 100 uF.

--Bob

Edit: Also, tantalum caps are not rated over about 35 volts.

 

[LDK180]

Is there a polarity marking? I don't see one, so I'm going to go with some sort of plastic film cap. Are they glass-sealed on the ends? If so, they are probably high-quality mylar or other polyfilm caps, like the old Sprague Vitamin-Q or Cornell-Dublier types. Tantalum caps are a type of electrolytic cap (and the tantalum is the metal foil inside, not the dielectric) and would have a polarity marking. Tantalum caps are easy to distinguish from ordinary aluminum electrolytics by virtue of their weight...they are quite heavy compared to aluminum caps, and they usually are not over 100 uF.

--Bob

Edit: Also, tantalum caps are not rated over about 35 volts.

Tantalum oxide, which forms on the tantalum, is the dielectric, so, in essence, you could say the tantalum is the dielectric.

 

[Matt]

They are a military spec part. The M83421 is a specific military spec. Do a google search and you will find more info then you want.