An externally hosted image should be here but it was not working when we last tested it.
I bought these caps of ebay a few years ago they are 10,000uf 80v elna I have just got a peak atlas ESR 70 which I hope is good enough to test caps with . the caps test within standard tolerances and esr seems nice and low the caps have the elna sword vent pattern what are your thoughts on these being fake . would be willing to cut one open if that's any good . 
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
You should reform them with an 80V power supply, and a 10k 1W series resistor for each capacitor,
to limit the current to less than 10mA at full voltage. Then slowly increase the voltage
from 0V to 80V over an hour or so while monitoring the drop across the resistor. When the
drop across the 10k is less than 10k x 1mA or 10V, the capacitor has reformed enough to use.
Last edited:
First you demonstrate that the caps are within spec. then you want to cut them open to prove what - that they are full of aluminium foil, interleaved with absorbent material and noxious, sticky electrolyte? You can't prove whether these parts are genuine or not by internal examination. The proof is in performance and this is only measurable with the capacitor intact.
So are you just bored or inquisitive to know what's inside?
https://en.wikipedia.org/wiki/Electrolytic_capacitor
So are you just bored or inquisitive to know what's inside?
https://en.wikipedia.org/wiki/Electrolytic_capacitor
They are excellent little meters, mines had a LOT of use
As for your caps?, I'm with the rest - they look fine, why would you suspect they aren't?.
The standard specification from all the manufacturers, I have read, state that the electrolytic capacitor must be reformed before any testing.
And reforming last week is no good.
It must be freshly reformed specially for the testing.
Last edited:
I think those are FAKES and you have been ROBBED BLIND.
Both *claim* 10000uF , yet one is a whopping 682uF short, the other one missing 650uF ... and so on.
But it's your fault, you should have *weighed* them when you received them, only way they were not filled to the top with capacitance, but some was left out.
Or at least, if a microgram calibrated scale was not nearby, you could have applied an old, savvy buyer's trick: you should have shaken each of them vigorously by your ear, any splashing inside would mean that vital capaciliquid was missing, and cheap *air* (ugh !!!) bubbles are present instead.
Both *claim* 10000uF , yet one is a whopping 682uF short, the other one missing 650uF ... and so on.
But it's your fault, you should have *weighed* them when you received them, only way they were not filled to the top with capacitance, but some was left out.
Or at least, if a microgram calibrated scale was not nearby, you could have applied an old, savvy buyer's trick: you should have shaken each of them vigorously by your ear, any splashing inside would mean that vital capaciliquid was missing, and cheap *air* (ugh !!!) bubbles are present instead.
That's the very first thing you should do. If I get a cap that's suspiciously light or feels hollow your damn right I bust one open and see what's inside. If they feel solid and measure in spec they're probably fine. When you do get a fake, they're going to put something really undersized in there - like the "10,000uf/50V" caps that had a little bitty 2200 soldered to the end cap. I finally got one of these - but it was a batch of 30,000uf/60V CG cans (paid like $5 a pop). The darn things felt empty - and sure enough there was a cheapo 4700 uf leaded cap hooked up inside it.
Are you SERIOUSLY showing us that you are measuring 0.02 ohm ESR with those crocodile clamps? Have you tried measuring them shorted? Or even better clamped one over the other onto the same terminal of the cap?
Measuring below 0.1 ohm with decent precision without a proper 4-wire setup is very much wishful thinking, as is trusting some of the figures from those cheap ESR meters without knowing the measurement method.
Also, it seems you have tested everything but the relevant parameter when it comes to suspicious caps - given that capacitance is within tolerance and your ESR measurement is essentially meaningless but definitely shows low ESR consistent with cap type and size - and that is leakage current. Simple reason: lower voltage caps are cheaper and jumping up even one step in voltage spec offers room for unscrupulous people to make money - even accounting for producing new shrink wrap with say, 63V stamped instead of 50V. Such parts will even work but fail very much prematurely (in a manner dependent on use). Leakage current is implicitly tested when (re)forming the cap. Another clue would be mechanical noises when the cap is shaken, but fakers have long figured out it is a clue so now they glue things inside.
All that being said, current commercial spec (2000hr life at maximum rated voltage and temperature) are built using pre-formed foil which results in far more predictable characteristics than in the olden days. As a result, given that the spec must hold within tolerance (i.e. the caps go just out of tolerance at end of life) it is extremely common for brand new and genuine capacitors to measure up to 10% below nominal value out of the box, and may not even reach nominal after forming. 10% less capacitance is 10% less foil is almost 10% material savings. Or, if you look at it differently, and you can given that if you get the basic same cap specified as long life (5000hr life under same conditions) it will be right at or slightly over nominal out of the box, you have increased yield by a whole lot just introducing two different specifications, and making in essence only one type of cap, then selecting which spec set it fits best into.
Measuring below 0.1 ohm with decent precision without a proper 4-wire setup is very much wishful thinking, as is trusting some of the figures from those cheap ESR meters without knowing the measurement method.
Also, it seems you have tested everything but the relevant parameter when it comes to suspicious caps - given that capacitance is within tolerance and your ESR measurement is essentially meaningless but definitely shows low ESR consistent with cap type and size - and that is leakage current. Simple reason: lower voltage caps are cheaper and jumping up even one step in voltage spec offers room for unscrupulous people to make money - even accounting for producing new shrink wrap with say, 63V stamped instead of 50V. Such parts will even work but fail very much prematurely (in a manner dependent on use). Leakage current is implicitly tested when (re)forming the cap. Another clue would be mechanical noises when the cap is shaken, but fakers have long figured out it is a clue so now they glue things inside.
All that being said, current commercial spec (2000hr life at maximum rated voltage and temperature) are built using pre-formed foil which results in far more predictable characteristics than in the olden days. As a result, given that the spec must hold within tolerance (i.e. the caps go just out of tolerance at end of life) it is extremely common for brand new and genuine capacitors to measure up to 10% below nominal value out of the box, and may not even reach nominal after forming. 10% less capacitance is 10% less foil is almost 10% material savings. Or, if you look at it differently, and you can given that if you get the basic same cap specified as long life (5000hr life under same conditions) it will be right at or slightly over nominal out of the box, you have increased yield by a whole lot just introducing two different specifications, and making in essence only one type of cap, then selecting which spec set it fits best into.
Yes, it's an EXCELLENT meter and designed to do just that
Perhaps you can't tell from the pictures but there's two wires to each clip, I don't know if they are simply paralleled or one is signal and the other sensing?.
In that case the two sides of the clip are wired separately and insulated but you can see clearly that they connect at the joint just like any ordinary alligator clip, except these are gold plated. I have a HP RLC meter which uses double clips and it came without them so I had to make my own and it's NOT easy. Proper clips of that kind can be had but a single one costs several of those RLC meters. It may indeed be possible there are separate sensing signals in there, but they are certainly not obvious. I've seen one version of this meter (albeit sold without a case), dead because of the cap not having been discharged, and no trace of sense returns, though.
Those are Kelvin connections, which are necessary in precision measurements.
For each lead, there is one contact for voltage, and one contact for current.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.