assessing internet purchases

[halaster79]

why do Rubicon MCZ caps tend to have lower UF than whats shown on the side of the caps? it still is in 20% tolerance though. numbers include like 1140 uf for a 1200 uf 6.3v MCZ cap. these are dated 2010 caps bought from badcaps and the cap king.

[halaster79]

Re: assessing internet purchases

my 2005 nichicon hm 1500uf 6.3v all seem to be in 1770 to 1830 range for uf. are they good?

[stj]

Re: assessing internet purchases

if the uF is noticably higher, can you read the leakage level or ESR on your tester?

i have seen capacitance rise with leakage, strangely the ESR goes down as it happens.

[Agent24]

Re: assessing internet purchases

They may have lost a little capacity over time from not being used, in any case, 1140uF for a 1200uF capacitor is pretty good.

AFAIK, Nichicon HM from ~2005 are not known to be very good! Yours may be showing higher capacitance from higher leakage current.

You need to check ESR and leakage current if you want to be really sure a capacitor is OK.

[halaster79]

Re: assessing internet purchases

i thought they were ok as long as they are in the range of +- 20% capacitance according to the datasheets? 20% of 1500 is 300, so wouldn't around 1800 be ok? on a 1500 cap read by a honeytek a6013L at 2000uf

[Agent24]

Re: assessing internet purchases

If the datasheet specifies the tolerance as +/-20% and they are within that, then sure, they are "within tolerances"

But. Manufacturing has improved over the decades, and it's not usual to find capacitors that are markedly different from the labels.

[halaster79]

Re: assessing internet purchases

i'm trying to figure out how to use a mesr-100 v2 esr meter now

[halaster79]

Re: assessing internet purchases

what does - 0 to 1 r mean? its reading .006 at that

[stj]

Re: assessing internet purchases

0.006 ohms esr

[halaster79]

Re: assessing internet purchases

is it normal for the ESR to be lower than what it says in the datasheets? especially when it says the ESR number is for ESR max in the datasheets?

[Agent24]

Re: assessing internet purchases

Yes. The datasheets show the maximum the ESR can be for a good capacitor. The actual parts may well have an ESR which is lower.

[halaster79]

Re: assessing internet purchases

do you guys consider the mesr-100 version 2 to be a good ESR reader?

i use an ideal 61-342 multi-meter and a honeytek A6013L capacitance tester to check capacitance. it takes the ideal longer to read it.