Jee caps

[nick122]

I've just pulled a slightly bulging jee cap from a psu. Its esr was 160! Whats's the biggest esr ever measured here on badcaps.net?

[ReeceyBurger123]

Re: Jee caps

My peak meter only goes to 40ohms no higher just says its failed lol

[ChaosLegionnaire]

Re: Jee caps

someone mentioned a bad kzg cap reading 2000 ohms esr? lol but i imagine some completely burst open junk caps can even read open circuit or infinite resistance lol

[Wester547]

Re: Jee caps

^ I don't recall that. I said in another thread that UCC specified a 5x11 0.1uF 50V SMG as having a maximum acceptable ESR of almost 2,000Ω ESR (at 20˚C and 120Hz) in the datasheet (which is ludicrous - it may as well be a resistor at that point). Highest recorded ESR of a failed KZG is 100Ω by PlainBill.

A capacitor that is open circuit would indeed have infinite resistance, suggesting the liquid electrolyte has completely dried up. A capacitor that is shorted (zero resistance) suggests great damage to the dielectric. A capacitor that reads fine for ESR but not capacitance denotes that the surface area of the aluminum oxide or foil has shrunken over time. It's a common failure mode for those capacitors based on organic solvents such as Ethylene Glycol or even γ-Butyrolactone. And it's probably why certain Rubycon series have a tendency to go out of spec in terms of capacitance as they age.

Jee has always been some of the worst bottom-of-the-barrel junk. No surprise one reads 160Ω. Some capacitors do fail to such an extent that no ESR or capacitance meter will give you a reading.

[mockingbird]

Re: Jee caps

^ I don't recall that. I said in another thread that UCC specified a 5x11 0.1uF 50V SMG as having a maximum acceptable ESR of almost 2,000Ω ESR (at 20˚C and 120Hz) in the datasheet (which is ludicrous - it may as well be a resistor at that point). Highest recorded ESR of a failed KZG is 100Ω by PlainBill.

A capacitor that is open circuit would indeed have infinite resistance, suggesting the liquid electrolyte has completely dried up. A capacitor that is shorted (zero resistance) suggests great damage to the dielectric. A capacitor that reads fine for ESR but not capacitance denotes that the surface area of the aluminum oxide or foil has shrunken over time. It's a common failure mode for those capacitors based on organic solvents such as Ethylene Glycol or even γ-Butyrolactone. And it's probably why certain Rubycon series have a tendency to go out of spec in terms of capacitance as they age.

Jee has always been some of the worst bottom-of-the-barrel junk. No surprise one reads 160Ω. Some capacitors do fail to such an extent that no ESR or capacitance meter will give you a reading.

Wester547 - what is the method of fatigue for a capacitor which tests within spec capacitance and ESR-wise, but has a high leakage current?

[Wester547]

Re: Jee caps

High leakage current = dramatically damaged or thinned oxide layer. That's why leakage current increases as capacitors sit in storage with no voltage across their plates (the oxide layer slowly dissolves into the solution until the capacitor is reformed and rebuilds the layer).

[TechGeek]

Re: Jee caps

jeez... these caps.