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Topic: 4 Legged capacitor?! (Read 12314 times) previous topic - next topic


strykeroz

Quote from: ebay-selller

no worry about the quality
My mind is at ease now :)
"There is no problem so bad you can't make it worse" - retired astronaut Chris Hadfield

fungus


Quote from: ebay-selller

no worry about the quality
My mind is at ease now :)


Joking aside, they actually sell them on digikey, etc:

http://media.digikey.com/pdf/Data%20Sheets/Nesscap%20URL%20links/ESHSR-0400C0-002R7.pdf

And yes, they can discharge at 237 amps. (although they're only rated for a pathetic 86 amps). That's quite scary...

Advanced Arduino

cjdelphi

Soooo the other 2 legs?  What do they do?

1ChicagoDave


Soooo the other 2 legs?  What do they do?


They're "blank". Probably for keying it -- so it can't be hooked up backwards?

http://media.digikey.com/pdf/Data%20Sheets/Nesscap%20URL%20links/ESHSR-0400C0-002R7.pdf

bigred1212

2.7v, 400f.   Hmmmm.

Sub this into a solar pummer circuit somehow?  Would it drive a standard LED all night?


fungus


Soooo the other 2 legs?  What do they do?


Have you ever connected an electrolytic capacitor backwards? (If not, try it...)

Now imagine doing it with a 400 Farad device...
Advanced Arduino

fungus


2.7v, 400f.   Hmmmm.

Sub this into a solar pummer circuit somehow?  Would it drive a standard LED all night?


If it can do 86 amps for 5 seconds then it can do 20mA for about six hours...but that's to discharge to half voltage so your LED would be dim. If you run at 10mA you might be OK but it would take two connected in series to keep your LED at 20mA all night.

Advanced Arduino

bigred1212

Hmmm.  I would have thought "connected in parallel" not series.

PedroDaGr8

Capacitors with extra legs are not uncommon. The extra legs serve TWO purposes. The first is to "key" the capacitor such that it only fits into the circuit one wya. When working with this level of energy density it is a good idea to do this. Second, they serve as additional mechanical connections to the board in order to stabilize and support the capacitor. These capacitors are large and heavy; note that it is 64mm (2.44 inches) long and 35mm (1.38mm) wide and weights 67g. This will have significant force in areas subject to vibration, often enough to either pull out the leads, break the solder joint or worse pull the cap right out of the board. As such, it is actually quite common to find 3 and 4 legged capacitors in larger can sizes. I have some Mallory caps in an old (but VERY nice) HP Precision 6114A power supply that have three and four legs. They are quite large (the largest is roughly the diameter of a can of red bull.

MarkT


Soooo the other 2 legs?  What do they do?


Partly for mechanical support, to protect against vibration fatiguing the other leads.
[ I DO NOT respond to personal messages, I WILL delete them unread, use the forum please ]

nickgammon


Quote from: ebay-selller

no worry about the quality
My mind is at ease now :)


Quote

we have sold many in our other shop, and all positive feedback, so you can buy directlly. no worry about the quality.


We only have to worry about the spelling. :)
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

cjdelphi

I have 2 400F caps and 2 200F caps.... i'm a little too scared to wire them wrongly, i have an attiny85 driving a 7hc595 and it goes for around 3 - 4 hours before the leds dim too much (wired in series making 5v)

cmiyc


Soooo the other 2 legs?  What do they do?

3-6 legs is common for "snap-in" style capacitors like this one.

Primarily they provide mechanical stability.  They can also help to reduce the ESR.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

7brian4

I found this 1 legged transistor with arms.

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