Capacitor Questions - which ones should I order?

[Superully]

i need to order some capacitors for a monitor repair (no cap kit available) and i'm somewhat lost in all the variety:

here are the search results for "Radial 105 °C220μF 10V DC" on rs online

i'm totally lost here - which ones should i order (panasonic?, how many mA, how many μA)? is radial 105 ok?

some input from the tech guys would be great!!! thx a lot

[liquidx]

Just buy the cheapest 105° one which you don't have to buy 50 of at a time, ignore other specs than capacitance and voltage.
I've never had a problem with their lower-end stuff. If you want to be really safe, grab the cheapest brand name.

If your spec sheet says 10v though, grab something a little higher, like 16 (never lower).

[Etienne MacGyver]

EDIT:
liquidx was just posting his reply while i was typing, ill post it anyway  
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Here something for the wiki  

that depends of your situation..
Radial has the connection in one side and axial one on each side:



manytimes on PCB they use radial, but sometimes axial.
I think you are reffering to radial, since that is in your query..

anyway, they are the same, its just the housing.
sometimes i use axial caps and bend one leg to the other side with some shrinktube
for example if the desired value does only exist in axial version at your supplier.
thats not the most elegant way, but it works..
(did that with gyruss monitor  )

then its just a matter of the correct uf value, this needs to be the same.
Voltage on the other hand can be higher than the original value, for example a 16V cap can be used without problems if the original was 10V

REMEMBER, NOT THE OTHERWAY AROUND!  so always go higher or the same voltage, then you won't have problems for that.

there are 85 degree caps and 105 degree caps, and even more higher temperatures, i like 105 degree caps especially in "hotter" areas.

and the last tip i can give is; WATCH the POLARITY ! so look how the cap is mounted before you remove it.

[Belike]

Useful topic, feels like some kind of arcade school.
Thanks for the teachers, it will be useful for noobs like me (and Ully).

[Muerto]

And me! 

[Superully]

If your spec sheet says 10v though, grab something a little higher, like 16 (never lower).

is that necessary? why not the exact same value?

[liquidx]

is that necessary? why not the exact same value?

It's not necessary, it's just a safety margin.

The voltage rating is how much voltage the capacitor can withstand; not the voltage across the circuit.
So if you have a 10v capacitor and you put a 16v one in, it'll work just fine, but it will be able to withstand a surge a little better than the original.

Take the analogy of water recipients. Say, you normally fill them with 5L of water, one has a 10L capacity, the other has a 16L capacity. Suddenly there's an increase in water flow and they start filling up more than usual. The smaller one will overflow before the bigger one.

Manufacturers tend to keep tolerance as close as possible to reduce costs, sometimes even too close (I have 2 netgear ethernet switches that blew recently because of that), so by putting in a higher value, you just make things a little more "solid". Also, the higher the voltage, the bigger the capacitor, so it could also have been a space problem back in the day, but they're all much smaller now anyway.

[Superully]

understood! but the μF value has to be the same?

[Etienne MacGyver]

understood! but the μF value has to be the same?

ALWAYS !

remember bruno's popeye issue ...

we really need a wiki here....   there are so many usefull  tips/facts from everybody in different specialities here...

would be great to put them all together..

[level42]

OK ding-dong, here comes mr. knows-it-better.

Cap value actually doesn't always need to be exactly the same BUT, and it's a big BUT (Miss Piggy's ?): you need to know what you are doing !

So.......for instance.....if a cap is used as a filter cap in a power supply, there is no problem if you use a HIGHER value capacity.

But again, in many OTHER applications (like "deeper" in monitor circuits) caps can be used in a (much) different way and the value can be very critical.

NEVER go lower on capacity and NEVER go lower on voltage, that is a golden rule.

Higher voltage is NEVER a problem (it just costs (a bit) more and the cap gets bigger physically).

In general, axial caps are more expensive than radial one's AND they are much harder to get nowadays.
In a lot of cases it's possible to use a radial cab in the place of an axial. It's not a beautiful sight though...

I personally always get a well-known brand like Nichicon or Panasonic.

[Superully]

another question: a manual lists a capacitor as follows: 6.8 (NP) 25V - what does the NP stand for?

[level42]

Non Polarized.

This means that this is an electrolytic cab that does not have a + or - side.

[Superully]

Non Polarized. This means that this is an electrolytic cab that does not have a + or - side.

great, thx andré, something new learned today. so this means it doesn't matter which orientation the capacitor is put in, right? do i have to order them separately or can i take a normal cap and simply not care about the +/- ?

[Etienne MacGyver]

nope you cannot
you need to order thisone seperately

[Superully]

nope you cannot
you need to order thisone seperately

thx etienne! but where do i find them on rs online? can you point me to the correct caps with the above-mentioned specs?