Advice on ESR and Capacitance meters

[Agent24]

I'm thinking of buying these, obviously without them my diagnostic method is limited to either:

1) Is it bulging/leaking?
2) Is it a Fuhjyyu?


Any recommendations on what I could get?
Are kits better or do they require expensive equipment to calibrate?

[larrymoencurly]

Re: Advice on ESR and Capacitance meters

I bought an original Bob Parker ESR meter kit (red LEDs), and it didn't need calibration, except for the low battery voltage. The instructions were very good, with the troubleshooting section listing lots of common mistakes, including the one I made (mix-up of resistor color bands). The only thing I didn't like was the insulator that went between the PC board and battery -- it was just a piece of corrugated cardboard that I thought might allow a short, so I replaced it with a piece of bare PC board material.

[Krankshaft]

Re: Advice on ESR and Capacitance meters

On the Blue ESR meter it needed both low battery voltage calibration and resistance calibration for the ESR readings. They included a 1% tolerance resistor and you had to adjust the POT to match it's resistance.

I'm sure the Dick Smith version had that too since the design changes on the blue board from the DS are subtle.

[Agent24]

Re: Advice on ESR and Capacitance meters

So the blue meter is recommended?

[kc8adu]

Re: Advice on ESR and Capacitance meters

So the blue meter is recommended?

my first choice.
i have several of the early dick smith kits.still fine after heavy use.
the blue is just pretty.same unit.

[Agent24]

Re: Advice on ESR and Capacitance meters

Does the Blue version have the protection diodes or is it only the Dick Smith kit which has these?

I was under the impression the Blue version does not...

[kc8adu]

Re: Advice on ESR and Capacitance meters

you can add the diodes to either.
i didnt as i use mine to check batteries.

[Agent24]

Re: Advice on ESR and Capacitance meters

Wait, what?

The manual for the MK-I Dick Smith version says

"Protection: Sooner or later this meter
will find itself connected to an unexpect-
edly charged capacitor (or worse), so
some protection has been built in. D3
D4, D5 and D6 are strategically placed
to prevent destructive voltages from
finding their way back to the microcon-
troller; D4 also limits the test voltage to
0.6V peak."

Looking at all 3 manuals for MK-I, MK-II and Blue they all use these diodes in similar places on the schematic...

Are these the same ones you are talking about?

[Krankshaft]

Re: Advice on ESR and Capacitance meters

The meter will take up to 50 volts I believe with it's integral protection.

They're talking about hefty high amperage diodes to save the meter from being connected to a charged line filter for example.

I installed my own set of back to back high amperage diodes on the output of the Blue once however it caused fluctuations in the meters output so I removed them.

[PCBONEZ]

Re: Advice on ESR and Capacitance meters

Wait, what?

The manual for the MK-I Dick Smith version says

"Protection: Sooner or later this meter
will find itself connected to an unexpect-
edly charged capacitor (or worse), so
some protection has been built in. D3
D4, D5 and D6 are strategically placed
to prevent destructive voltages from
finding their way back to the microcon-
troller; D4 also limits the test voltage to
0.6V peak."

Looking at all 3 manuals for MK-I, MK-II and Blue they all use these diodes in similar places on the schematic...

Are these the same ones you are talking about?

Not the same diodes.
There is a mod to add protection against connecting to undischarged high volt caps.

I added them to my MK-II and it works fine.

[Agent24]

Re: Advice on ESR and Capacitance meters

How does one go about adding that mod then?

[PCBONEZ]

Re: Advice on ESR and Capacitance meters

Read page 12 under "Heavy Duty Protection".
https://cdn.badcaps-static.com/pdfs/...323c887511.pdf
Those diodes are fairly big.
You'll need to be creative to get them inside the unit.
Just barely fit in the MK-II. Dunno how you'd get them into the blue one.
.

[Toasty]

Re: Advice on ESR and Capacitance meters

Inline 100-200mA fuse.

[Krankshaft]

Re: Advice on ESR and Capacitance meters

The IN5404 diodes mod can be done with the Blue.

You solder them to the solder side of the PCB right where the output probes solder in.

I was able to bend them in such a way that they fit and the board would reinstall into the casing.

I guess a fuse would add too much ESR? That does seem like the simpler solution. But I'm sure there's a reason that the diode method was developed.

[Toasty]

Re: Advice on ESR and Capacitance meters

Fuse does not add to much ESR. It is compensated for when you setup/calibrate the unit and zeroed every time you use it. It is ahead of those protection diodes on 1 of the the incoming leads. If you hit a too highly charged cap, it pops, saving the meter from the inrush high current. Low current was chosen so that it would fail quickly, saving the meter. The diodes do their part on low charge ones.

I want to try a MOV at some point to further protect, but that's an experiment for another day. The fuse solution works for me.

I went with a small glass pigtail fuse, but a pico fuse would do just as well.

Toast

[PCBONEZ]

Re: Advice on ESR and Capacitance meters

What is the response time of a fuse compared to the response time of a diode?
I dunno, I didn't look it up, but
I'm pretty sure a fuse burning open is considerably slower than a diode begining to conduct.
Also don't have to keep track of spare 'oops' fuse[s].

Another consideration is if you use a 120v fuse and hit a cap charged to 450v or something the current can arc right through the fuse body.

I put my diodes on the back side of the lead jacks so they are between the PCB and the cap under test.

MOV idea sounds interesting.

Last time I did anything like blowing a meter was back in the 80's anyway.
It's just fun dinkin' around with the toys, um, I mean test equipment.
.

[lucky13]

Re: Advice on ESR and Capacitance meters

After pondering on the Blue ESR meter for a long time, I finally bought the ESR-Micro from Russin Mike. I like it very much. The only thing is the leads. They are not your test probe length and style (i.e., removable). However, it is very small and compact.

I use the alternate mode to read the capacitance & ESR and it is so good to see both w/o using two different meters.

Look into it.

[ecking767]

Re: Advice on ESR and Capacitance meters

Hello, I just purchase The Blue ESR meter kit and it was easy to assembly and to calibrate. Its have an easy to read chart and so I was testing caps with-in an hour. There is nothing I will change on this setup, the test leads are OK for now. It works great. hope this help you in your decision

[Toasty]

Re: Advice on ESR and Capacitance meters

@ ecking767 -
>>There is nothing I will change on this setup,<<

You should consider putting in the back-to-back diodes for protection, unless you're going to use it to check batteries.

Toast

[ecking767]

Re: Advice on ESR and Capacitance meters

Toasty- I have a printed label on my meter saying " dis-charge caps" so I don't make a costly mistake and burn out my esr meter. So I not going to make any changes. Thanks for the advise !!