Tantalum capacitors - Who buys them? - Page 2

Here's a diagram

Are all epoxy coated caps tantalum?

I get some of these tantalum capacitors from circuit boards that come from CNC Machines, Computerized Metal Lathes, Mazak Machines and the like. I probably have a few pounds of these capacitors in a little tupperware container. I will probably sell them all once I have several pounds of them.


I must say though, I agree with GeorgeB. HOW MUCH DO THEY SELL FOR PER POUND??!!!!!!!!!???

I, also would like to know 'roughly' the price. Tantalum is a new item for me. I have a bunch of circuit boards saved up, and I'm tempted to go through them all and do some clipping. $1 per lb? $30 per lb?
Ebay is showing me 10 capacitors = Roughly $2-$3 but that is mostly for Re-use, not scrap.

I wonder how many it would take to make a pound. Haven't seen any prices yet but if 50.00 is right I'll start saving them.

Originally Posted by NMatheson

I would be very interested in learning how to identify these caps. I've looked around a bit and can't find any solid info on identification. Anyone have any pointers?

Hi

It is very easy to learn about their codes and types. As you look at above Pic. the capacitor has 3 numbers on it. All you need is to know what those codes represent.

Normally codes are 3 digit's but represented in 2 digits as well : If code is 2 digit then it is directly represented in Pico Farad.

47 = 47 pf

If code is 3 digit then first two digit give value and last one gives multiplier as :

104 = 10 X 0000 (4 zero's) pf = 10,0000 pf = 0.1 uF

On some capacitors a Letter is also printed ; which shows tolerances of that capacitor : as

D = +/- 0.5 pF
F = +/- 1%
G = +/- 2%
H = +/- 3%
J = +/- 5%
K = +/- 10%
M = +/- 20%
P = +100% ,-0%
Z = +80%, -20%

You can search out internet for more information on these !

Regards

I read through all of the links and came to the conclusion that it could look like almost any other IC on the board. Bottom line: Is there a specific way for a tantalum novice to pick through their material and recognize it?

edit: i saw where you posted more info while i was researching

wow please tell me i have some of these tantalum her i would realy like to know how to identify these put money in my pocket and not the steel bin

Some info in this thread on the "other" forum: Gold Refining Forum.com • View topic - tantalum capacitors
Hope that it gives you what you're looking for!

I have found from this site that the Tanti caps have a 'direction'. Ie they are labled positive or negative on one leg.

The others I get are the SMD caps, little grey or white blocks soldered onto the board, some are yellow (larger ones) with markings on them & one black painted end on it.

Actually they tell you right on the board, have a good look, every cap has its position & individual number labled on it. Normally its just a C12 or C13 or C14 or such. C being 'Capactor' & the number is for the indivudial caps number, so you can find its value.

I scrapped a G5 CPU thing & there was 20 grams of SMD caps on it before removing the solder. I desoldered (HCL Acid) 140 grams & got back 135gms of Caps.

"Which part is the tantalum, the colored body or the silver metallic legs or all of it?"

The Ta part is under the polymer it is a sinister powder pellet with a Ta wire extending out of it. the leeds are almost always nickel. They a commonly confused with monolithic capacitors that are in through hole form(not the SMDs). The three main types ane cans, through hole, and SMD. The cans can both be foil or sinistered Ta pellet with a layer of tantalum pentoxide around them. The through holes are best described as looking like fish. Althe some are barrel, square, and blocks with a point. The SMD can be the common yellow, black, blue and RED(they look like monolithic capacitors but are red) The black and blue are commonly misidentified with diodes. You can tell the difference by looking at the boards. The capacitor will have a c##s, or a z###s. but the diode will have a D###s

The best way to identify the Ta caps is to remove the outer shell but fire or grinding.

most scrap yards will not buy them unless you have hundreds of pounds.

I can answer any other questions I'm not an expert on them but I do collect(buy) them.

Eric

the picture that you show from wikipedia Tantalum capacitor - Wikipedia, the free encyclopedia looks to be showing the difference of the markings of polarity between Al caps and Ta caps.

If you have any question on if it is Ta or Al put som HCL or maybe vinegar will work but if there is a reaction than it is AL.

Eric