View Full Version : capacitor question


Rich12
05-22-2016, 07:50 AM
Hi everyone I'm very new to restoration , if I need to for example replace an 8 350 paper cap what is the modern equivalent? For example I only see 10's in electrolytic caps not film. I also understand I can use higher voltage but everything I see in film is .47 or .68 I don't see any 8 or 10.

old_tv_nut
05-22-2016, 07:24 PM
8 seems an unlikely value - can you post a picture?

N2IXK
05-22-2016, 07:52 PM
I agree that 8 uF is an extremely large value for a "paper cap", which are generally under 1 uF. Are you sure you aren't talking about an electrolytic?

Electrolytic caps generally have a VERY wide tolerance anyway (like -20%/+100%), so substituting the closest modern value is almost always acceptable.

8 uF was once a standard value but not anymore. Unless in a critical circuit, a 10 uF replacement would be just fine.

Electronic M
05-22-2016, 10:14 PM
I believe 8.2uF is a modern standard value, but a 10 ought to work.

wkand
05-23-2016, 11:18 AM
Hi everyone I'm very new to restoration , if I need to for example replace an 8 350 paper cap what is the modern equivalent? For example I only see 10's in electrolytic caps not film. I also understand I can use higher voltage but everything I see in film is .47 or .68 I don't see any 8 or 10.

Hi Rich12:

it is likely that the 8 uF 350 volt paper cap you reference is an electrolytic. If it is wrapped in a cardboard tube, this may be leading you to believe that it is a paper cap. As old-tv-nut says, a picture would be the best way to clear this up.

What we mean by paper is the dielectric material that separates the metal plates of the capacitor. In a tubular cap, the plates (usually some form of foil) are wrapped together, then sealed in ceramic, wax or plastic. The cap could have a plastic outside covering, and still be paper dielectric, and therefore needing to be replaced.

the value of the cap combined with its working voltage is the giveaway. You are correct in your observation that the poly replacement caps do not come in 8 uF values.

Make sense?

Walt Anderson

Rich12
05-24-2016, 01:51 PM
Here is a pic attached thanks guys!

Rich12
05-24-2016, 01:54 PM
Thanks Walt, I thought I was somewhat on the right track

old_tv_nut
05-24-2016, 01:55 PM
The large value (8 microfarads) combined with a polarity (the positive side is marked) indicate that this is an electrolytic capacitor. A slightly greater value (10 microfarad), 250 volt or somewhat greater, electrolytic should work fine. Make sure the replacement is installed with the same polarity or you will have a loud bang and exploded capacitor contents everywhere.

Rich12
05-24-2016, 03:21 PM
Thank You!