esr or cap tester

[RusMike]

Re: esr or cap tester

I received my ESR-Micro V4 today.

I'm new to this type of device.

I was testing a unsoldered 470uf 35V radial cap using the probes, how do I know if the cap is good? I heard a bird chirp and the E reading was .12 and C reading was 452 and according to the manual the cap is good. So this 470uf 35v cap is good right?

What does a bad cap sound like or read when using the Micro v4.0 meter?
I need to measure a 2200uf 16V radial cap but it's not listed in the
http://www.prc68.com/I/Capacitors.shtml

Or what does a good cap sound like or read when using the Micro v4.0 meter?

The criteria is about - more than 1000uF - ESR < 0.1ohm, 100...1000uF - 0.2-0.5ohm is normal. You also can just check new caps and take a look at readings

[frosch11]

Re: esr or cap tester

Hi All,

some month ago I bought the ESR-micro V4 from Mike. Wow! I love it. It is easy to use and gives reliable informations about caps.

Last week I´ve checked the diplexer electronic of my loudspeakers. I changed some caps, because their values do not match with the schematics anymore. And now, they sound a bit better!

Very good device.
Thats it :-)

[elbtax]

Re: esr or cap tester

Ordered from Mike on 5-8-2010. Projected delivery to east coast, USA was 5-22 thru 5-25. Received my order on 5-27-2010. Was very pleased with Russian post shipping. I had capped a Gateway Fpd1960 prior to receiving the micro 4.0 that was displaying 2sec to black. Replaced all caps with Nichicon. I still got 2sec to black. Got the micro 4.0 and checked my supply of Nichicon caps. The 220uf, 25v caps had been in my bin for around two years. Checked esr and they had gone high. Should have been around .23 but was reading .48.. Ordered pan fm from digikey and replaced. Great joy now. Thanks to Mikes pet i now know even new caps that have been sitting around for a year + can go bad. I recommend Mikes meters, and especially for hobbyist like myself. The whole transaction with Mike was a true pleasure.
Happy capping!!

[smason]

Re: esr or cap tester

Just got my ESR Micro today! Forgot it on my desk at work, so won't get to try it till tomorrow night.

[bp1]

Re: esr or cap tester

Got my esrmicro 4 from mike today. Like everyone else the product is great.
Took 10 days in the post - Defantly worth the wait.
Mike replies to emails very quickly and the price is very competative.
Highly recommend this meter for the toolbox at his great budget price.

Kind Regards
bp1

[vo_danh]

Re: esr or cap tester

Im thourougly convinced by all the craze here I just put in my order at http://www.prc68.com/I/Capacitors.shtml
for $75 it was a no brainer pre-built and with such good reviews. I can't wait to get mine.

[ukvince]

Re: esr or cap tester

Hi to everyone as i'm a newbie here...
Can someone please tell me where i can order an ESR-Micro v4. The link is probably here somewhere and i have looked (i promise) but i'm tired and can't find a it .. ... so pretty please with sugar on top give me a link...

[PCBONEZ]

Re: esr or cap tester

Out of production.
http://www.radiodevices.info/zakaz_e.php

[ukvince]

Re: esr or cap tester

Thanks....PCBONEZ

[RusMike]

Re: esr or cap tester

Can someone please tell me where i can order an ESR-Micro v4. pretty please with sugar on top give me a link...

Hi ukvince, I just sent email to you
Yes there are some problems with ver.4.0, but I didn't know you are from here.
For "Badcaps guys" I can find something somewhere under my workbench
Check your mailbox

[RusMike]

Re: esr or cap tester

Btw all ESRmicro4.0 user can change it to "deadless". While we are testing this adding we tried to kill device with caps charged to 350V, but we couldn't! This schematic just don't allow to connect probes to unit while cap is charged
See picture at here: http://www.radiodevices.ru/forum/ind...c=3.msg167#new
( file "protect.gif" at the bottom of page ) Soon our black pet will be able to compete with AtlasESR70

[bp1]

Re: esr or cap tester

RusMike - Cannot seem to see the "protect.gif"

[RusMike]

Re: esr or cap tester

put it here
better to load zip, as I could not insert file with its normal size

[martyb]

Re: esr or cap tester

so is it possible to see the schematic of the russian meter or is that a closely guarded secret??????

[RusMike]

Re: esr or cap tester

It has never been secret
some components values may differ from this schematic (as well microcontroller's dump) but common sense remains the same...

[twixt]

Re: esr or cap tester

Btw all ESRmicro4.0 user can change it to "deadless". While we are testing this adding we tried to kill device with caps charged to 350V, but we couldn't! This schematic just don't allow to connect probes to unit while cap is charged

Hi, Mike. When will production of the ESRmicro4.0 be available with the "deadless" feature?

I have checked your website and read about the production delays and the proposed timeframe for when new units will be available again - which should be shortly according to the latest info.

Please let me know when I will be able to order and receive a "deadless" ESRmicro 4.0. Thanks.

[RusMike]

Re: esr or cap tester

Hi Twixt,
the circuit is already changed a bit. The common sense remains the same, BUT you don't need to push the button after every testing. Device defines cap is connected, then it checks for DC, if all OK (cap not charged) it switches relay connecting probes to front end of unit. Then after about 3-4 measuring cycles ( 4 sec.) it automatically disconnect probes. Prototype is working well and consumption is about 2mA. It remains THE ONLY way to kill pet - if you force relay to switch probes (say just connecting probes or so...) and AFTER THAT within 4 sec.( while probes are already connected ), connect charged cap. I have already crashed my crazy brain trying to solve this LAST problem... How to do that device looking for DC while it already turns to working mode??? I think it is just impossible... any suggestions???

[twixt]

Re: esr or cap tester

Hi Twixt,

[stuff deleted in the interest of brevity]

It remains THE ONLY way to kill pet - if you force relay to switch probes (say just connecting probes or so...) and AFTER THAT within 4 sec.( while probes are already connected ), connect charged cap. I have already crashed my crazy brain trying to solve this LAST problem... How to do that device looking for DC while it already turns to working mode??? I think it is just impossible... any suggestions???

Hi, Mike. There are a couple of ways to bulletproof that situation:


System 1

1. Your original design uses less than 0.6v for the test - so the test can be performed in-circuit without causing conduction in the semiconductors in-circuit with the capacitor under test. The protection circuit must therefore be sensitive enough to detect any condition which causes the voltage to rise above the level where any semiconductors in the circuit under test can start conducting and therefore affect the test - while being robust enough to withstand the voltage produced if a charged capacitor is connected to the circuit while the pet is in its ESR or capacitor-value-sensing mode.

2. Design a circuit that monitors for current through the back-to-back protection diodes on the input - which happens when you have enough voltage in the circuit under test for the diodes to conduct. If you have sufficient voltage to achieve conduction in the protection diodes - open the circuit to the pet's input and restart the cap-discharge process.

You do this by adding a small resistance in series with the protection diodes. Monitor the voltage drop across this resistor. Should the resistor start producing a voltage drop - it indicates that one or the other of the protection diodes is conducting.

Having a differential op-amp input across the resistor and adjusting the gain suitably, with a comparison against a Vref - where the circuit is polarity independent - will produce an op-amp output that indicates when either one of the protection diodes is conducting, but ignores any leakage current in the before-threshold-is-reached condition. (Typical polarity-independent Schmitt Trigger situation.)

The output of the op-amp when current is flowing through either protection diode toggles the relay to open the connection to the pet's input and begins the capacitor-discharge cycle again.

3. The existing silicon diodes used for the protection circuit must be sized to survive the current through one or the other of the protection diodes for the short time it takes for the protection circuit to disconnect the pet from the input leads. You will have to experiment to see how much dissipation will actually occur in the few-milliseconds transition timeframe - and adjust the size and ratings of your silicon protection diodes and the wattage of the current-sensing-resistor accordingly.

Note: Relays react in timeframes thousands to millions of times longer than those in electronic circuits - but that relay is required in your discharge circuit in order to get sufficient current flow in discharge mode to discharge a highly-charged large-value-capacitor in a reasonable amount of time. Therefore, things that happen in the transition time between the sensing of a voltage that should not be present on the input to the pet - and the time it takes for the relay to open the circuit to the pet's input - must be accounted for.


System 2

Monitor the voltage across the existing back-to-back diode-pair. Look for the *presence* of a too-high voltage across the diode-pair, indicating that either diode is conducting during the measurement phase. If the voltage drop increases (indicating that either diode has been biased into conduction to the point where it is carrying substantial current) the op-amp causes the relay to break the connection to the pet and begin the cap-discharge process again.

This circuit is cranky. Forward conduction voltage-drop across a silicon diode
does vary with current. However, the voltage variation is very small - and the conduction-threshold-voltage varies with temperature. Production variations in batches of diodes can also affect the conduction-threshold voltage - such that the diodes will have to be matched, you need a temperature compensation circuit, and the op-amp's threshold voltages must be fine-tuned to the particular set of diodes installed in the pet. And if either diode in a diode set fails, another matched set must be installed and calibrated before the pet is safe to use again. More trouble than it's worth IMO.


System 3 - Further protection for either System 1 or System 2:

1. For the capacitor-discharge circuit to protect against someone putting a protected pet in-circuit with the power turned on - you can use another set of op-amp inputs as a ripple-voltage detector. Should the protection circuit detect the presence of ripple - this means the circuit under test is not powered off and the discharge function should not be performed at all. This is the very first test performed - and it protects the circuit under test from the near-short-circuit condition that occurs when a supposedly-unpowered capacitor is being discharged. This requires two relays - one which keeps the pet disconnected from the test leads until a safe condition is detected, and another which will not energize the cap-discharge-relay until the source of ripple is removed.


IMO, this would be a great feature that would differentiate your unit from the Atlas ESR Plus. I suggest that this circuit be installed regardless of whether System 1 or System 2 is employed. However, System 3 is optional.

And if a user is trying to check a capacitor far enough downstream of the rectifiers or switching transistors that there is insufficient ripple to cause the ripple-detector to activate - then you'll just have to admit that you can't protect against that level of stupidity.


Hope this helps.

[RusMike]

Re: esr or cap tester

twixt, THANKS for your excellent ideas!!! We will be thinking. First I will try to set supressor SMCJ5.0 instead of these diodes. May be that will be enough
Although:
"...you can't protect against that level of stupidity."
everyone can find the way to kill device if HE REALLY WANT THAT

[mariushm]

Re: esr or cap tester

Mike, are the ESR Micro 3.1 available?

I'm interested in one but it's now listed at 50$ - if I remember correctly it used to be about 1000 rubles or around 35$... Yes, looks like it, http://www.radiodevices.info/zakaz.php still lists it at that price.

This is much closer to what I would be willing to pay for something like this, plus the shipping to Romania where I live which shouldn't be too much.

Any special deals for Badcaps forum users?