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Electronics => Repair => Topic started by: mitch on November 30, 2019, 08:50:01 am

Title: Capacitor voltage rating range?
Post by: mitch on November 30, 2019, 08:50:01 am
I have a capasitor that's rating is 189...227uF and Un 250V~/Up 275V~ I found one that is 189...227 and 220-250 volt.

My question is will the 220-250 volt capacitor work with the 250-275 volt? They both are rated for 250 volts, right? Is that rating a range between the two numbers?

(https://i.imgur.com/hLGXIEP.png)
New?
https://www.amazon.com/gp/product/B00C0VZA0W/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B00C0VZA0W/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1)
Title: Re: Capacitor voltage rating range?
Post by: trobbins on November 30, 2019, 10:11:55 pm
Un is the rated continous rms max voltage.  Up is a short duration, limited no of events, peak rms level that doesn't cause degradation. Similar to electrolytic ratings that comply with xxxx standard.
Title: Re: Capacitor voltage rating range?
Post by: mitch on December 01, 2019, 04:43:38 am
Un is the rated continous rms max voltage.  Up is a short duration, limited no of events, peak rms level that doesn't cause degradation. Similar to electrolytic ratings that comply with xxxx standard.

So Un220 & Up250 for the one on Amazon, so it could work?
I'm completely new to electronics.
Title: Re: Capacitor voltage rating range?
Post by: bob91343 on December 01, 2019, 04:54:40 am
The closer you run a capacitor to its voltage rating, the lower its reliability.  So using the lower voltage unit won't cause immediate problems but the long run is grim.

It's usually wise to provide a voltage rating higher than necessary in order to stave off the degradation that occurs with more voltage stress.  Once the capacitor develops a slight leak in current, that warms it and raises the temperature.  And temperature is the primary cause of failure.