Cheaper ESR meter

[mmir2012]

Re: Cheaper ESR meter

I made it on Veroboard but hence it is not working. I need step by step trouble shooting or checking that where is the fault. I think you will help me in this matter. Please mention the test point to make the esr meter. Thanks

[vecky]

Re: Cheaper ESR meter

If any one is beginning to consider circuit design I offer this experimenter to whoever might want it.
It was my first in the line of prototyping boards. It's been in a junk box for years and years and I used and abused it.
During one late night test I smoked the pots out of it so your first experiment would be a rebuild of the unit. Have no manual but if someone wants this PM me and I'll send it. This is for a beginer or learner and I'm in the US only.

Hello arneson, I think that writing to you
I am new in this forum and maybe I am interested for your experimental board
because I need all that function on the same place for testing purpose.
Thanks in advance.

[ai8h]

Re: Cheaper ESR meter

Alrighty then - Almost 2 months later and it is all in a box working and useful. Changed to a smaller 0-1v meter, but can see that .05 ohm target ... about 3 needle widths off full scale on the lower scale. Added an extra range - switch to the right selects on the meter scale. Upper-right corner is the 'short' indicator. Binding posts to the right are to attach to a bench supply vs the coaxial wall wart connection above it.

Hand drawn scale! But will finish when a minor problem ironed-out, like a slight op amp offset problem. The zero adjust control is a must with the diode detector insensitivity to temperature.

Attached a before transfer from proto board and after. An extra-fun project!

[ai8h]

Re: Cheaper ESR meter

Hi Gang. I have just been working with a protoboard prototype of this ESR meter. It works great per the original article. Have made a few modifications such as using a pair of TL082s (virtual ground source and oscillator in one and the rest in the other), along with mods to expand the range down to .05 ohms (not yet determined, exactly). However, the pair of 22 ohm resistors can be changed to 10 ohms each in the bridge with good results. Using a GIANT 200uA meter that also helps tremendously. I have used the oscilloscope method for years to match capacitors in a series string of high voltage power caps, but this thing is super! And GS3's circuit description is great!

[whiz]

Re: Cheaper ESR meter

Did anything further ever come of this project? is there a finalised design somewhere?

Yes there is a PCB layout with parts list etc on this link...

http://www.yoreparo.com/foros/diseno...ico/39157.html

from my personal experiance i'm not satisfied neither from gs3's modifications
nor from the original design...

i'm using a PCB layout which is the same design as the above and you can
find it here:

http://www.yoreparo.com/foros/diseno...ico/80575.html

i'm using it with analog multimeter and resistors with 1% tolerance for the wheatstone bridge. Although it works i can't understand much...

With most used and brand new capacitors the multimeter neadle goes close to the end of the multimeter scale that i have regulated it. (about 300uA) and the differences that outputs in most of the cases are few uA (6-7uA)...which is not noticable with my analog multimeter, only with my digital.

For capacitors with the same value these small differences in current (uA) probably indicates small tolerance differences in capacitance or maybe small deterioration or faulty capacitor from the factory (high ESR evidance) but i think i need a capacitometer so i can conclude anything from the above.

In small and very small capacitors the esr meter either it doesn't output anything..or it outputs much less current and the neadle falls close to zero!probably due to corner frequency of the small capacitors (?) again the differences between the small capacitors is few uA! and my multimeter
is not so sensitive to read them!

i tryed some of gs3's recomendations... which he has said on the second link i posted. the one is that we can use a 1N4148 diode at the output to the multimeter so we can suppress the range (i didn't like it) and the second recomendation is to exchage R15-R16 (47K with 27K resistors) to solve a problem with the neadle that shows less when the probes are shorted and more when you test a capacitor. (this modification i think it lowers the gain (?) and makes the esr meter not to amplify enough the output signal...so
less sensitive in capacitor differences.


i'm not an expert but these are my opinions from the little things
i know on electronics. If somebody else has build it, i would like to
read his opinions!

[Kaine]

Re: Cheaper ESR meter

oh yay i won't be resurrecting this thread too much.

Did anything further ever come of this project? is there a finalised design somewhere?

[whiz]

Re: Cheaper ESR meter

I have build the esr meter from the links gs3 gave and works...although with some problems.

[Bob Parker]

Re: Cheaper ESR meter

It might work with a 4069 though - I should have some of them in the stocks.

I don't think it'll work with a 4069, because the oscillator section depends on the hysteresis of that inverter.

[starfury1]

Re: Cheaper ESR meter

Hi Harvey, All
yeah I know how it goes...lol was just wondering
I should really have scrounge around myself....
not that I do much electronics these days, maybe its time to stoke up the iron

Cheers Harvey All

[Harvey]

Re: Cheaper ESR meter

Actually, I forgot all about it I'll have to have a look over the weekend to see if I can find a HC14, but I've a gut feeling I've not not one, as its always the case that anything I actually want I've never got.

Hundreds of other 74 and 4000 chips, but never quite the right one I want....

It might work with a 4069 though - I should have some of them in the stocks.

[starfury1]

Re: Cheaper ESR meter

Hi Harvey

just wondering if you did knock one (of the above) up?

Haven't had a close look but think its really more "go/ no go tester".
From what I understand ESR when it goes it goes big time, in orders of magnitude
so it probably to some extend hinging on this fact.

Still I guess some type of ESR meter is better then none.

Anyway like I said just wondering

Cheers

[Harvey]

Re: Cheaper ESR meter

I might, if I can find a 74HC14 in my boxes of junk, give this http://members.shaw.ca/swstuff/esrmeter.html a go over the next few days.
To me it looks too simple to be accurate, but time will tell.

[gregmcc]

Re: Cheaper ESR meter

I've build the ESR meter from here and can't seem to get it to work. I would appreciate a few pointers.


IC1A is generating a square wave. The collector is TR1 is shown here

and the collector of TR2 is here

If I short the cap out the RED should come on but it doesn't. The pins 5 and 6 of IC1 are both 0V

Any tips of where I could be going wrong. Any more scope screenshots of points would be helpfull.

[techjoe]

Re: Cheaper ESR meter

I like this simple design and planing to build it, but before I jump in to it, should I use a multimeter or one of those analog amp meter.. what is the best route?

also is this work reliably?


Thanks in Advance.

[Raven21633]

Re: Cheaper ESR meter

Bob Parkers Digital ESR is among the best but you still have to shell out quite a pretty penny to get one. If you have a wife to account to (who's not so happy about what your spending on parts for your antique radios as it is) you have to look for less expensive solutions.

That's actually how I found this forum. I was planning to build the Nuova Elettronica ESR bridge and was desperately searching for anyone who sells a 1nf (10µf) Metalized Polyester or Mylar caps in the USA (the closest I came to the North American coastline was Ireland) when Google hit upon this thread I'm very happy it did! This looks like a wonderful project!

Raven

[klq]

Re: Cheaper ESR meter

Regarding the schematic at the start of this thread can any one tell me what the diode next to r21 is? Also what are the resister values in brackets? Many thanks

[repairs online]

Re: Cheaper ESR meter

Hello,

That proves my point, an analogue display ESR meter would pick up the faulty from the good ones easily without having to spent time on looking for capacitance values and voltages off the caps.

The only problem is with caps below 10 uF, perhaps special circuitry installed at the flick of a switch will take care of it.

Sincerely

[willawake]

Re: Cheaper ESR meter

i also noticed that caps tend to be good or very bad by the time i am looking at a repair

same here, since i am looking at low esr caps only they are usually 0.0X when good and 0.XX or even X.XX when bad.

[kc8adu]

Re: Cheaper ESR meter

i have the opposite experiance.
the low end resolution of the bob parker design is better.
btw i have the code here i found online so i can program a new micro if need be.
i also noticed that caps tend to be good or very bad by the time i am looking at a repair.

[repairs online]

Re: Cheaper ESR meter

Hello,

I already have Bob Parker ESR meter. However, the analog type, in my opinion, are much better, easier to read.

With Bob Parkers ESR, it becomes essential to look at the value of the capacitor and then compare it with the value on the table, however, this problem does not exist for the analogue meters I have read about, it is either good or is bad.

Getting a digital readout is not really such a great idea. What does it mean if the reading is slightly higher than the value indicated on the panel, the cap is bad????, I don't think so, I brought brand new caps where the reading was higher than indicated and they worked fine.

Reseting is also a problem with this digital ESR meter.

Of course, repairing the meter is another factor, if the micro on Bob's meter becomes defective ....well try to find another micro. Further, it can easily be damaged by charged caps.