200v caps in place of 50v caps

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STEvil

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I know you can use "overrated" caps, but is there a limit on how overboard you can go?

All i've got are these 200v 1000uf caps.. would rather have 100v or 50v 2000uf caps as thats closer to what were originally in place (Pyramid PB480 amplifier with a couple 50v 1000uf caps that broke off from vibration I guess).
 
It should work fine. The voltage rating only signifies at what point the dielectric will break down, but since the capacity is still 1000uF it will work.
 
higher voltage caps have thicker dielectrics, which increases their ESR. Also, the size of electrolytic caps increases exponentially with higher voltage ratings...

For most applications, if you can fit the 200V parts in there, you'll be fine. If it's going in a switching power supply or anything where ESR matters, then get the proper 50V caps.
 
Originally posted by gee
higher voltage caps have thicker dielectrics, which increases their ESR...
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But they also have higher ripple current rating, which may help in an audio amp psu.
 
Originally posted by cpemma
But they also have higher ripple current rating, which may help in an audio amp psu.
Click to expand...
quite the opposite; high voltage caps, with their higher ESR, tend to have lower ripple current ratings. After all, ripple current is equal to max power dissipation divided by ESR...
 
They're too tall and will look like ass on their side (see-through top on the amp).

Just gonna get some 50v caps that are 1500uf or better.
 
Originally posted by STEvil
They're too tall and will look like ass on their side (see-through top on the amp).

Just gonna get some 50v caps that are 1500uf or better.
Click to expand...

i'd put in the same uF that was in there before, as that can really affect things... voltage of the caps won't make much of a difference.
 
It can?

What kind of things specifically (i'll learn it all eventually ;) )?
 
Originally posted by gee
quite the opposite; high voltage caps, with their higher ESR, tend to have lower ripple current ratings. After all, ripple current is equal to max power dissipation divided by ESR...
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That clashes with Dubilier's CLP Snap-in 85C PCB electrolytics specs in my catalogue:

63V 1000uF: ESR 0.15R, Ripple 1.32A
200V 1000uF: ESR 0.199R, Ripple 2.80A

Granted, for a given ripple current the cap with the higher ESR will generate more heat, but arguably a bigger mass & surface area (as higher voltage ones tend to have) will result in a lower temperature rise and/or allow for a higher safe ripple current.
 
Originally posted by STEvil
It can?

What kind of things specifically (i'll learn it all eventually ;) )?
Click to expand...

the voltage rating on a capacitor is basically just how much it can handle... the uF is what matters.

whenever you do circuit analysis, nobody ever calculates what voltage of a capacitor you need, as it doesn't really matter, they calculate what uF you need... basically, it'll effect the time constant, which in lay-mens terms... means a larger cap could potentially slow down your circuit.
 
Higher voltage won't matter too much, however 200V is much higher than I would be happy with because of the ESR.

More capacitance is always a good thing in amplifiers, although car amps are a little funny in that you shouldn't put in too much more than what was there originally.
 
Originally posted by chopsuwe
More capacitance is always a good thing in amplifiers, although car amps are a little funny in that you shouldn't put in too much more than what was there originally.
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Being that its an unknown circuit, I want to disagree. But being that its an amplifier, I can only think of one situation. Sometimes car amps have a built in active or passive crossover. If that cap is part of the crossover, then it will change crossover points and whatnot.
 
How about exploring the novel idea of actually replacing those caps with the right ones? :(
Here I will even make it real easy for you.....


Digi-Key Part Number P10333-ND
Description CAP 1000UF 50V ELECT FC RADIAL


Now back to your question......
Assuming larger caps fit they are certainly going to be of lesser quality then the crap that amp had in it to begin with, if you are willing to take a quality hit on a already low quality amp be my guest. :D

BTW. I have 26 of those Panasonic caps on hand.... shoot me a pm and I will drop a few in the mail first thing in the morning. :)
 
The ones that were in there were 50v Caricon 2200uf, I was just going to use whatever I could find as temp replacements until I could order some.

Thanks for the offer, though ;)

Current list of stuff to order:

- 3x PIC16C71-04I/P (MIG welding board - seach datasheet also?)
- 2x 50v 2200uf+ low ESR caps
- 2x 100k VR
- 2x 50k VR
- 2x 10k VR
- 12x 200uf+ 16v low ESR ceramic caps

Now to get on the phone and check to see if the "local" electronics shop can get the IC's.. The damn things are for a circuit board from a MIG welder that costs $1500 CAD new, and $1000 CAD to FIX :eek:

Maybe I can figure out why that IC is being burnt out all the time, too.. Peice of motorola crap.. :D
 
oh no, spend the $5US and get a new welder :p

Originally posted by STEvil
Now to get on the phone and check to see if the "local" electronics shop can get the IC's.. The damn things are for a circuit board from a MIG welder that costs $1500 CAD new, and $1000 CAD to FIX :eek:
Click to expand...
 
$5US for a welder? :rolleyes:

I'm fixing this one for an autobody/mechanic guy that lives near me since the board is apparently only manf'd in sweden or some crap... go figure.
 
If that welder has a dead PIC, then you're gonna have to call up the welder manufacturer and get the new code for the PIC.

Which they probably won't give you... they might mail you a preprogrammed PIC though, for an obscene price.
 
It's a Microchip (http://www.microchip.com) RISC microcontroller, actually. Motorola microcontrollers and microprocessors have 68xxx or MPC in front of them ;)

Either way, buying another PIC chip and putting it in won't work, you'll have to get either a preprogrammed replacement chip from the welder company (which they might do) or get them to send you the code on the chip (which they'll most likely not do)
 
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