Bad cap reading 4x high?

[jayjr1105]

I have a swollen Sanyo WG 2200uf cap removed from the board and reading 8000uf with an LCR meter and a DMM. I always thought bad caps capacitance goes way down when swollen or leaking.

[budm]

Re: Bad cap reading 4x high?

What resistance do you get when tested it in Ohm mode? What ESR do you get when tested with ESR meter?

[stj]

Re: Bad cap reading 4x high?

high leakage does that.

[jayjr1105]

Re: Bad cap reading 4x high?

What resistance do you get when tested it in Ohm mode? What ESR do you get when tested with ESR meter?

Starts around 1k ohms then climbs and climbs then, in a split second, goes up to 30k.

[eccerr0r]

Re: Bad cap reading 4x high?

I've seen some LCR meters report incorrect numbers on leaky capacitors. The number is wrong.

[sam_sam_sam]

Re: Bad cap reading 4x high?

First off the ESR 0.24 ohms is a give away any way

It should be .02 anyway and the UF reading is way off to

[jayjr1105]

Re: Bad cap reading 4x high?

First off the ESR 0.24 ohms is a give away any way

It should be .02 anyway and the UF reading is way off to

I'm not too sure about the ESR accuracy on that cheap test kit. I have thrown brand new low esr caps in there and it's shown way too high esr as well.

Here is an example. Brand new 1000uf Panasonic FM

[stj]

Re: Bad cap reading 4x high?

they are very accurate if they are calibrated.

[retiredcaps]

Re: Bad cap reading 4x high?

IBrand new 1000uf Panasonic FM

Electrolytic caps are usually +/- 20% of their uF rating. So a 1000uF cap reading 1048uF is okay.

The ESR might be a bit high depending on which exact 1000uF cap you have. Check it against

https://cdn.badcaps-static.com/pdfs/...404c12c252.pdf

[jayjr1105]

Re: Bad cap reading 4x high?

they are very accurate if they are calibrated.

I just ordered a .1uf cap to calibrate it. I don't have anything close sadly.

Electrolytic caps are usually +/- 20% of their uF rating. So a 1000uF cap reading 1048uF is okay.

The ESR might be a bit high depending on which exact 1000uF cap you have. Check it against

https://cdn.badcaps-static.com/pdfs/...404c12c252.pdf

I didn't mean the capacitance. I meant the ESR is way too high for a brand new low ESR cap.

[Stefan Payne]

Re: Bad cap reading 4x high?

Electrolytic caps are usually +/- 20% of their uF rating. So a 1000uF cap reading 1048uF is okay.

Yes, smaller ones are usually a bit over that.

Bigger ones (=High Voltage) usually are a bit under the specified value.

ie for a 470uF capacitor you can assume something around 440uF or something like that...

[stj]

Re: Bad cap reading 4x high?

i recommend a 0.22uf film cap for calibrating.

if a .1uf cap is actually 0.099uf the tester wont like it.

[budm]

Re: Bad cap reading 4x high?

It looks like the leakage resistance causes the fault capacitance reading.
If you put 100K, 47K resistor in parallel with that Panasonic cap, what will it show on your cap meter?

[jayjr1105]

Re: Bad cap reading 4x high?

i recommend a 0.22uf film cap for calibrating.

if a .1uf cap is actually 0.099uf the tester wont like it.

Figures, I knew I should have just ordered a kit like this. http://a.co/3KgqGtE

Do you think my ESR readings will improve that much once calibrated? I have tested a ton of low esr caps, never once seeing anything .0X or lower. I thought that LCR tester is just junk.

Edit: I can put two .1uf's in parallel can't I?

[stj]

Re: Bad cap reading 4x high?

the parallel method should work.

you should read my very long tester thread!!
https://www.badcaps.net/forum/showthread.php?t=50720

[victor_cj]

Re: Bad cap reading 4x high?

they are very accurate if they are calibrated.

LCR-T4 versus BK 880
https://streamable.com/acx9m

[victor_cj]

Re: Bad cap reading 4x high?

1-6-4 Temperature Characteristics

Aluminum electrolytic capacitors have liquid electrolyte. This electrolyte has properties (conductivity, viscosity, etc.) that have rather conspicuous temperature characteristics.

Electrical conductivity increases as the temperature increases and reduces as the temperature decreases.

Therefore, the electrical characteristics of aluminum electrolytics are affected by temperature more than other types of capacitors. The following section explains the relationship between temperature and capacitance, tangent delta, ESR, impedance and leakage current.



1) Capacitance The capacitance of aluminum electrolytic capacitors increases as the temperature increases and decreases as the temperature decreases. The relationship between temperature and capacitance is shown in Fig. 1-9.



2) Tanδ, Equivalent Series Resistance (ESR), Impedance The Tanδ, equivalent series resistance (ESR) and impedance changes with temperature and frequency. An example of the general characteristics is shown in Fig. 1- 10 and 1-11.

[victor_cj]

Re: Bad cap reading 4x high?

https://www.youtube.com/watch?v=vzoDurlg_jI

[jayjr1105]

Re: Bad cap reading 4x high?

LCR-T4 versus BK 880
https://streamable.com/acx9m

I have never from day 1 of owning the LCR-T4 seen a cap ESR that low. Even with brand new caps. I wonder if there's firmware or something to update. I still have some caps coming tomorrow for calibration.

[victor_cj]

Re: Bad cap reading 4x high?

>0.1uF capacitor for calibration is the reference, Rp and Rs may make a difference.
On the LCR-T4 PCB, 431(TL431) is the reference for ATMEGA328P-AU.