Problems with ceramic capacitors run at near their rated voltage?

[treez]

Hello,
Supposing I use a 50V , 10uF , X7R, 10% capacitor on a 48V rail. The closeness of the rail to the capacitor’s rated voltage means that the actual capacitance will be much less than 10uF. –Though will the tolerance be worse aswell?….ie will the tolerance on the capacitance be much worse than 10% now?

 

[goldsmith]

Hello,
Supposing I use a 50V , 10uF , X7R, 10% capacitor on a 48V rail. The closeness of the rail to the capacitor’s rated voltage means that the actual capacitance will be much less than 10uF. –Though will the tolerance be worse aswell?….ie will the tolerance on the capacitance be much worse than 10% now?

Hi treez
It really depends on what company made that capacitor . because i have had it in several times that the capacitor was made in china and it marked that the tolerance is around 10 percent but when i used that i understood that that's a lie ! it was around 25 percent ! but when i used a good one instead , everything became right . after my first time which i was facing such a problem i always try to buy from best manufacturers .

I hope i could help .
Best Wishes
Goldsmith

 

[FvM]

I'm not aware of min/max specifications for capacitance voltage dependency. Respectively there's no guaranteed tolerance for biased capacitance.

In my view, it's not reasonable to use high dielectric constant capacitors above 50 or 60 percent of rated voltage.

 

[Gorgon]

Normally the capacitance will be specified over the temperature range, and lowest in the extremes.