DIY 555esr meter & Old Roe

[alessioblaupunkt]

I've built the ESR meter that I found at this address.
My digital DC Voltmeter got no button to set ZERO volt on display, so when I supply the 555esrMeter the two boundaries are:
No cap at test point = 1.355V
Shorted test point = 0.069V

The fine adjust sensitivity 1 V/ohm is not working properly in my circuit so please don't think the value is the real esr in ohm.

I've tested over 100 different electrolytics with this circuit, but I don't understand how much reliable this meter could be.

For example: I've tested these 47uF electrolytics:
[year 2011, new] Sanyo ME AX 47uF 100V = 0.108
[year 2010, new] Yageo SEK 47uF 250V = 0.226
[year 2008, new] Jamicon TK 47uF 63V = 0.182
[year 2002, used] Lelon RGA 47uF 50V = 0.200
[year 1991, used] Rubycon CEW 47uF 100V = 0.208

Then I take 3 Roe electrolytics, 47uF:
[year 1987, used] ROE EGD 47uF 250V = 0.082

Could it be? After 24 years they are better than a modern low esr 47uF electrolytic such as Sanyo?

[PCBONEZ]

Re: DIY 555esr meter & Old Roe

May be partially shorted.
Same condition as causes excessive leakage current.
-
Do they show the same [or at least low] ohms without the ESR meter?
-

[alessioblaupunkt]

Re: DIY 555esr meter & Old Roe

Sorry, I forgot to say everytime I test a cap I follow this sequence:
1- I check the DC resistance by charging the capacitor through a 2.28 kohm resistor.
For the porpouse I use an analog ohmmeter, it will supply the RC series by its own test leads.
Inside the ohmmeter there is a 3V battery, but I never measure what's the voltage between test leads.
Using the ohm x1000 scale, every good 47uF capacitor will hit the value xx (kohm).
Rarely occurs the capacitor has a capacitance bigger than its printed value, as a result the needle of the ohmmeter will hit ( say xx-1) a smaller value than my capacitance&resistance table.
If the capacitor is in bad condition, the needle will hit (say xx+1) a bigger value than my table.

2- I check the leakage current:
After charging the capacitor, I check how much current it will draw from the battery through the resistor
in three steps: after 5 minutes, after 30 minutes and after 12 hours.
During this test it's very important that nobody (an animal, a baby, a baloon, my mother)
will hit the capacitor placed on a wood container with only air in intimate contact with capacitor leads
( yeah, sometimes there is humidity in the air, but it will not make such a big difference).
Sometimes dielectric absorption will increase the voltage in the capacitor, so when I'm going to test how much current it will draw in reality it will GIVE me current. This is as funny as real.
Many years ago I wrote a table with several capacitance value and their possible leakage current,
so I decide if the capacitor is good, bad or if it's going bad.

Only if the capacitor passes these two selections I'll check the esr value.
You may ask why: Because I recently discover this behaviour, thanks to years of DC resistance and leakage current measurement and (recently) to the 555esrMeter:

If capacitor will not passes DC resistance test, its esr will not be good.
But a capacitor with a good esr could fail the DC resistance test, because its capacitance could be decreased:
I have a 680uF general porpouse electrolytics with good esr ( 0.094) that fail the DC resistance test, it gives me half the value I normally expected from a 680uF.

So these ROE arent' shorted.

[PCBONEZ]

Re: DIY 555esr meter & Old Roe

In reading elsewhere those are audio caps and they are Low ESR.
.
They are rated at 100Hz and 10kHz though so I dunno what it should be at 100kHz.
.
.

Couldn't find your value but here's one from same series:

250v - 220 uF - 25x45mm
tan δ 100 Hz MAX.: 0.07
ESR @ 100 Hz (Ω): 0.505 Ω
Z @ 10 kHz MAX. (Ω): 0.195 Ω
IR 100 Hz TUC (A): 1.075 A

.

[alessioblaupunkt]

Re: DIY 555esr meter & Old Roe

Thank you very much.
These caps were placed after three diodes that rectifiers the voltage coming from the secondary winding of the switching transformer in a colour crt tv.

The bottom gaskets are in very good condition and sniffing at the bottom they don't smell, so I'm going to reuse these in the tv because for the moment I can't find nothing better.

[TheLaw]

Re: DIY 555esr meter & Old Roe

Sorry to butt in...but this ESR meter seems kind of attractive? Are there any protections built in?

[TheLaw]

Re: DIY 555esr meter & Old Roe

By the way, I just came across those same caps the other day in my bin...They have so little weight to them.

[alessioblaupunkt]

Re: DIY 555esr meter & Old Roe

The only protection available in this meter consist in two diodes BY255.
If you plug in the meter a charged cap, they will discharge it.

But I always discharge the cap through a 2.28 kohm resistor, before any measure.

If you want more information, you could ask directly to the user "frako" of this forum, I think he made this 555esrmeter.

I modded his project to improve the range, if you reverse D04 ( the schottky ) you could read different values of esr in the range 470uF to 2200uF, in the original project there are no big difference reading the esr value of a capacitor with capacitance range between 470 uF and 2200 uF.

If you need specific protection, ask me what you need and I care about this.

[neuron]

Re: DIY 555esr meter & Old Roe

Sorry, I forgot to say everytime I test a cap I follow this sequence:
1- I check the DC resistance by charging the capacitor through a 2.28 kohm resistor.
For the porpouse I use an analog ohmmeter, it will supply the RC series by its own test leads.
Inside the ohmmeter there is a 3V battery, but I never measure what's the voltage between test leads.
Using the ohm x1000 scale, every good 47uF capacitor will hit the value xx (kohm).
Rarely occurs the capacitor has a capacitance bigger than its printed value, as a result the needle of the ohmmeter will hit ( say xx-1) a smaller value than my capacitance&resistance table.
If the capacitor is in bad condition, the needle will hit (say xx+1) a bigger value than my table.

2- I check the leakage current:
After charging the capacitor, I check how much current it will draw from the battery through the resistor
in three steps: after 5 minutes, after 30 minutes and after 12 hours.
During this test it's very important that nobody (an animal, a baby, a baloon, my mother)
will hit the capacitor placed on a wood container with only air in intimate contact with capacitor leads
( yeah, sometimes there is humidity in the air, but it will not make such a big difference).
Sometimes dielectric absorption will increase the voltage in the capacitor, so when I'm going to test how much current it will draw in reality it will GIVE me current. This is as funny as real.
Many years ago I wrote a table with several capacitance value and their possible leakage current,
so I decide if the capacitor is good, bad or if it's going bad.

1 - 2.28 KOhm any partic. reason for this value?

2 - First we need to charge with the label voltage ... to check I>leakage current for this brand and company
and then test 5, 30 min and 12 H.

Best regards,

Neuron

[gearhead63]

Re: DIY 555esr meter & Old Roe

I use my old Eico 950b, it will charge to about 500v. I also have a B&K 801, and I use my scope and signal generator for quick tests. I've also used my Lambda regulated PS to charge up low voltage caps. If the current doesn't drop quickly then it's probably not good. I don't waste a lot of time though as most caps are cheaper than the time to test them. Just my opinion.

[neuron]

Re: DIY 555esr meter & Old Roe

I use my old Eico 950b, it will charge to about 500v. I also have a B&K 801, and I use my scope and signal generator for quick tests. I've also used my Lambda regulated PS to charge up low voltage caps. If the current doesn't drop quickly then it's probably not good. I don't waste a lot of time though as most caps are cheaper than the time to test them. Just my opinion.

Yes but all equip. cost alot.

" I use my scope and signal generator for quick tests."

Please provide more details.

Regards,
Neuron

[stj]

Re: DIY 555esr meter & Old Roe

curve plotiing?
that's oldschool!

[budm]

Re: DIY 555esr meter & Old Roe

@neuron: plenty of information out there.
https://cdn.badcaps-static.com/pdfs/...29baf4e186.pdf
http://meettechniek.info/passive/capacitance.html

http://geoffg.net/Measuring_ESR.html

[Majestyk]

Re: DIY 555esr meter & Old Roe

The higher the voltage of an electrolytic capacitor (given the same capacity) the better the ESR will be.
So you cannot really compare ESRs of a 50V and a 250V cap.

0.082 is not too far from the Sanyo 100V with 0.108.
The Yageo would be comparable voltagewise but I assume the quality of the Yageo isn´t very good.

ROE by the way stands for "Roederstein" a German brand.

[alessioblaupunkt]

Re: DIY 555esr meter & Old Roe

Sorry got no personall or smartphone to answer.
Here I am so it's time to replay:

neuron 1):
I apply the 2.28 Kohm resistor only if the capacitance is less than 470uF.
That 2.28 kOhm resistor in series with the capacitor gives an RC time constant.
The meter also takes some time to reach the minimum resistance value on the right side of the Ohm scale.
My analog ohmeter gives me good reading from 1.0uF to 4700uF.

I made a table with these value:

Reading on the ohmeter while charging the capacitor with its internal battery and the 2.28 kohm resistor:
R+ 1 uF -> 400 kohm
R+ 2.2uF -> 250 kohm
R+ 4.7uF -> 150 kohm
R+ 10 uF -> 80 kohm
R+ 22 uF -> 50 kohm
R+ 47 uF -> 30 kohm
R+ 100 uF -> 17 kohm
R+ 150 uF -> 15 kohm
R+ 220 uF -> 11 kohm
R+ 330 uF -> 9 kohm
R+ 470 uF -> 8 kohm
1000 uF -> 2.8 kohm
1500 uF -> 2 kohm
2200 uF -> 1.6 kohm
4700 uF -> 1 kohm

Maximum discharge current through the 2.28 kohm resistor:

R+ 1 uF -> 3 uA
R+ 2.2uF -> 6 uA
R+ 4.7uF -> 10 uA
R+ 10 uF -> 25 uA
R+ 22 uF -> 36 uA
R+ 47 uF -> 100 uA
R+ 100 uF -> 150 uA
R+ 150 uF -> 180 uA
R+ 220 uF -> 235 uA
R+ 330 uF -> 250 uA
R+ 470 uF -> 300 uA
R+ 1000 uF -> 360 uA
R+ 1500 uF -> 390 uA
R+ 2200 uF -> 410 uA
R+ 4700 uF -> 460 uA

You all should take these two tables with a grain of salt:
analog meter made by other brand could give different reading because of different internal circuitry
and different voltage of the battery.

neuron 2): No need to charge the capacitor with the label voltage: just use an LCR meter.
My cousin has the Wayne Kerr 4225: it has a 2V internal generator and if you need you can select the 100V generator.

Handshake to all of you.

[neuron]

Re: DIY 555esr meter & Old Roe

Sorry got no personall or smartphone to answer.
Here I am so it's time to replay:

neuron 1):
I apply the 2.28 Kohm resistor only if the capacitance is greater than 470uF.
That 2.28 kOhm resistor in series with the capacitor gives an RC time constant.
The meter also takes some time to reach the minimum resistance value on the right side of the Ohm scale.
My analog ohmeter gives me good reading from 1.0uF to 4700uF.

I made a table with these value:

Reading on the ohmeter while charging the capacitor with its internal battery and the 2.28 kohm resistor:
R+ 1 uF -> 400 kohm
R+ 2.2uF -> 250 kohm
R+ 4.7uF -> 150 kohm
R+ 10 uF -> 80 kohm
R+ 22 uF -> 50 kohm
R+ 47 uF -> 30 kohm
R+ 100 uF -> 17 kohm
R+ 150 uF -> 15 kohm
R+ 220 uF -> 11 kohm
R+ 330 uF -> 9 kohm
R+ 470 uF -> 8 kohm
1000 uF -> 2.8 kohm
1500 uF -> 2 kohm
2200 uF -> 1.6 kohm
4700 uF -> 1 kohm

Discharging current through the 2.28 kohm resistor:

R+ 1 uF -> 3 uA
R+ 2.2uF -> 6 uA
R+ 4.7uF -> 10 uA
R+ 10 uF -> 25 uA
R+ 22 uF -> 36 uA
R+ 47 uF -> 100 uA
R+ 100 uF -> 150 uA
R+ 150 uF -> 180 uA
R+ 220 uF -> 235 uA
R+ 330 uF -> 250 uA
R+ 470 uF -> 300 uA
R+ 1000 uF -> 360 uA
R+ 1500 uF -> 390 uA
R+ 2200 uF -> 410 uA
R+ 4700 uF -> 460 uA

You all should take these two tables with a grain of salt:
analog meter made by other brand could give different reading because of different internal circuitry
and different voltage of the battery.

neuron 2): No need to charge the capacitor with the label voltage: just use an LCR meter.
My cousin has the Wayne Kerr 4225: it has a 2V internal generator and if you need you can select the 100V generator.

Handshake to all of you.

Thank you,

1)
"I apply the 2.28 Kohm resistor only if the capacitance is greater than 470uF."

Hum ... but in this table is < 470 uF !!!!!!!




Table nº 2
"Discharging current through the 2.28 kohm resistor"

This apply to 5 minutes or 30 minutes or 12 hours ???




2)

"No need to charge the capacitor with the label voltage: just use an LCR meter."

Well many members in this forum don't agree ...
You could test with this Volt.,
but we have other Volt. to carry Sencore LC 53, 77, 102

Please read the post gearhead63


Thank you for your valuable info,
Neuron

[alessioblaupunkt]

Re: DIY 555esr meter & Old Roe

I can't edit so I'll ask some moderator to do that. Thank you for reporting.
"I apply the 2.28 Kohm resistor only if the capacitance is LESSER than 470uF."


Table nº 2 is the consequence of the first table:
You charge the capacitor with the ohmeter (internal battery 1.5V) through R (if it is required)
The second table show the MAXIMUM discharging current through the 2.28K resistor.
Discharging time depends on the capacitance:
a 4700uF cap will reach the maximum discharge current of 460uA in 1 second and the needle
of the ammeter reaches 0 in circa 30 seconds.

Don't have the time right now but I'll upload a 4 minutes video (charge+discharge).
I'll insert the link in this post.

I don't guarante these are valuable info because these are selfmade and could be wrong.

Thank you.

[neuron]

Re: DIY 555esr meter & Old Roe

I can't edit so I'll ask some moderator to do that. Thank you for reporting.
"I apply the 2.28 Kohm resistor only if the capacitance is LESSER than 470uF."


Table nº 2 is the consequence of the first table:
You charge the capacitor with the ohmeter (internal battery 1.5V) through R (if it is required)
The second table show the MAXIMUM discharging current through the 2.28K resistor.
Discharging time depends on the capacitance:
a 4700uF cap will reach the maximum discharge current of 460uA in 1 second and the needle
of the ammeter reaches 0 in circa 30 seconds.

Don't have the time right now but I'll upload a 4 minutes video (charge+discharge).
I'll insert the link in this post.

I don't guarante these are valuable info because these are selfmade and could be wrong.

Thank you.

Thank you so much for your help and info.

If you have any other valuable info I and other members appreciate.

Best regards,
Neuron

[stj]

Re: DIY 555esr meter & Old Roe

here is a simpler but more advanced ESR meter - this is the one often seen on chinese ebay sites.
(it's often cheaper to buy than build btw.)

http://www.mikrocontroller.net/artic...ansistortester
it also tests semiconductors.
the latest one can spec zener diodes too!

[alessioblaupunkt]

Re: DIY 555esr meter & Old Roe

Yes thread is about ESR meter but let me clarify: posts 9, 15, 16, 17, 18
are OT because we were speaking about dc resistance test of a capacitor, with an analogue meter.

Some days ago I tested 3 Yageo SEK 47uF 250V with the Wayne Kerr 4225 LCR meter and here are the results:

Capacitance Dissipation factor    Res@100Hz      Res@10KHz
45.85 uF      0.0485       1.685 ohm      0.888 ohm
46.96 uF      0.0495	    1.677 ohm      0.899 ohm
39.90 uF      0.0575	    2.293 ohm      0.981 ohm

I also tested 3 brand new unused Panasonic EE 47uF 250V, same LCR meter:

Capacitance Dissipation factor     Res@100Hz	  Res@10KHz
41.40 uF      0.0180        0.685 ohm      0.225 ohm
40.87 uF 	  0.0183        0.711 ohm	   0.217 ohm
41.16 uF	  0.0176        0.678 ohm	   0.218 ohm

SEK are standard capacitor for 100Hz application, EE are suitable for switching PSU output stage.

Please note new capacitor must be supplied at nominal voltage or lower voltage for a couple of
hours to show real value.

As an example I tested a brand new, unused Panasonic NHG 10000 uF 16V capacitor and it shows:

Capacitance Dissipation factor     Res@100Hz      Res@10KHz
12.90 mF        -        0.533 ohm      1.06 ohm

After 1 week at 12V for 24 hours/day these are the results
(removed from the circuit and discharged, tested for three weeks, 1 time at week):

Capacitance Dissipation factor     Res@100Hz	    Res@10KHz
9960 uF       0.250	     0.040 ohm      0.038 ohm