View Full Version : Capacitor Size Matter?
stealth17
10-01-2005, 06:09 PM
Does the physical size of a capacitor matter? Like a tiny 16v 1000uf just as good as a large 16v 1000uf?
Also what about voltage? I have a mod that needs 6.3v or 16v caps, but will 25v of the same uf rating work fine?
SoddemFX
10-02-2005, 07:38 AM
Not strictly, but if the leads are too long (because of the increased physical size) you'll introduce more series inductance.
Voltage, always leave a little head room at least, but yes you can use caps. rated for higher voltages.
Depends what you want to do(?)
What i would do is to use bulk electolytic where i had significant low frequency ripple, low ESR electrolytics if you can. Then put in some small 10-50nF ceramics close to the current drain your trying to clean up the supply voltage to, this will remove the higher freq. noise...
Good luck with whatever you're planning :)
Tom
iddqd
10-07-2005, 10:38 AM
It's not the size, it's how you use it ;)
[sorry, I had to]
k0nsl
10-07-2005, 11:17 AM
It's not the size, it's how you use it ;)
[sorry, I had to]
Hehe, just to illustrate, you don't want to replace your old capacitors with leiden jars :D
-k0nsl
jahjahbinks
10-07-2005, 01:16 PM
Then there is Black Gate caps for people with fat wallets.
Some audio people I know claim that they can tell that different brand of caps can make music sound differently. well, i always thought that's a bit extreme.
stealth17
10-07-2005, 03:50 PM
Not strictly, but if the leads are too long (because of the increased physical size) you'll introduce more series inductance.
Voltage, always leave a little head room at least, but yes you can use caps. rated for higher voltages.
Depends what you want to do(?)
What i would do is to use bulk electolytic where i had significant low frequency ripple, low ESR electrolytics if you can. Then put in some small 10-50nF ceramics close to the current drain your trying to clean up the supply voltage to, this will remove the higher freq. noise...
Good luck with whatever you're planning :)
Tom
How do I know if its got low frequency ripple?
jahjahbinks
10-08-2005, 01:08 PM
Use a scope.
SoddemFX
10-08-2005, 01:41 PM
^Its the only way, unless you have a spectrum analyser :D
Tom
stealth17
10-08-2005, 01:58 PM
Dont have either :(
SoddemFX
10-08-2005, 02:16 PM
You can get a nice workable scope for £80 - £100 second hand here in the UK. Its a lot of money but if youre interested in electronics it would make a great investment :)
The spectrum analyser i was being silly :D They would be very usefull but cost many a dollar...
Maybe go and speak to your nearest college electronics dept. and explain what you'd like to do. They'd probably be more than happy for you to come in some time and even assist you...
Tom
sluggo
10-09-2005, 08:33 PM
If you see two electrolytic caps with the same voltage, ripple, and capacitance specs, then the larger will most likely have a lower ESR.
A cap with a higher voltage rating is okay, and may even be preferable, but once you're at 2x the working voltage (say, 10V ona 5V line), you're past the point of diminishing returns.
For a motherboard application, I would try to find a cap with the right voltage and capacitance, and find it in a commercial temperature spec (105 degrees C).
sluggo