I have several 15 mF capacitors for a compressor. Measured several of them, and they come in at 14.5 mF. Never at 15. 14.5 mFarad is within the +-5% deviation, but I am wondering if there is a pattern, ie.: this is some way to save materials for manufacturer, or maybe this is temperature related?
Yeah, capacitors ALWAYS seem to be on the LOW side !
It's a specification numbers game I'm pretty sure.
Quote from: boB on April 22, 2014, 09:40:32 PM
Yeah, capacitors ALWAYS seem to be on the LOW side !
It's a specification numbers game I'm pretty sure.
Back when dinosaurs roamed the Earth and I learned this stuff my feeble memory recalls many components were actually +- 20%.
I am pretty sure it is a numbers game. a few square meters of foil & insulator over a run of a few million capacitors probably saves enough to "justify" a target value below rating but within what they call manufacturing tolerances. :o
Or not.
Tom
Quote from: TomW on April 23, 2014, 09:19:18 AM
Quote from: boB on April 22, 2014, 09:40:32 PM
Yeah, capacitors ALWAYS seem to be on the LOW side !
It's a specification numbers game I'm pretty sure.
Back when dinosaurs roamed the Earth and I learned this stuff my feeble memory recalls many components were actually +- 20%.
I am pretty sure it is a numbers game. a few square meters of foil & insulator over a run of a few million capacitors probably saves enough to "justify" a target value below rating but within what they call manufacturing tolerances. :o
Or not.
Tom
Yes, I also seem to remember specs something like +5% -20% on electrolytic capacitors. Might have been +10 % but it was lop-sided.