I've been measuring F&T bipolar electrolytic caps 100VDC (black axial) for speaker crossovers for years. All are +10% with capacity as a rule. That's not good either. Most Chinese film capacitors (Bennic for example) are -10%. Wima foil PP capacitors (even some copies) are of fairly accurate capacity. Boutique expensive foil caps (Mundorf, Jantzen etc.) are always the exact capacity with small deviations. Nichicon, Elna, Nippon Chemicon, Panasonic electrolytic caps are generally OK, a little plus or a little minus.
It all depends on where they are used. Bipolar caps in speaker crossovers, +-10% deviation is too much. Polarized electrolytic caps in power supplies, +-20% no big deal. That doesn't say much about the quality of the caps. The only thing is that the buyer may feel robbed when he receives a lower value.
Better all a bit lower/higher in value but within tolerance and all around the same value than wild deviations and necessary matching.
I just measure my Nippon Chemicon 4 ky 35V 2200uf, about -5% ~-10% ,
It won't have any negative impact in my PSU, I trust their quality and specs.
Esr, voltage tolerance, lifetime, temperature tolerance.
It won't have any negative impact in my PSU, I trust their quality and specs.
Esr, voltage tolerance, lifetime, temperature tolerance.