Capacitor tester ESR Meter PCB done

I made the ESR meter that New York Dave mentioned in this thread:
http://www.groupdiy.com/index.php?topic=30545.0

I built this, it uses and easily sourced 1ma meter, and it works great.
here's a PDF Package which includes schematic, PCB layout and calibration operation info.
I made it for a pretty large trimpot format so you might have to use a sharpie and modify this to fit what you have.
:I just noticed on the overlay the IC is marked LM325 Osmond PCB likes to increment part numbers like that : values on the schematic are correct.
both ICs are LM324
download the pdf here
http://www.twin-x.com/groupdiy/albums/userpics/ESRMeter.pdf

Thanks to everybody here for all the great projects!
Hope someone finds this useful.  Happy new year!
Sleeper

EDIT: Updated layout 8/16/09

Sorry, but link opens the gmail site.... or I'm missing something :-\

Hi Moby
Hmm,
It works when I click it. I uploaded the pdf as per instructions at the bottom of the meta meta - to the group diy gmail site and then pasted a link to the email location.
On my firefox (mac) a double click on the link opens a download window and asks if you want to open or save the linked PDF.
this works even if I'm NOT signed in to the gmail account.
Admin?
Sleeper

That just points to a cookie on your own computer on your mail account. Never going to work here in any form.

Try an alternative solution.

OK, did it the old way, somebody please tell me if it works now.
Sleeper

Link works  I like old school style 

Started building this yesterday, the PCB Layout has an error.
On IC1,  pin 10 should connect to pin 14 (not 13)

Haven't got mine working yet, driving me nuts.
Seems ok until IC 2D then somethings messed up.
Getting the same voltage on pins 12, 13 and 14.
I'll have another crack at it tomorrow.

Hi Mr. Clunk,
Thanks for the heads up, you are right about that trace error, I'll fix that when I have some time.... I wonder why mine still works perfectly...  ( I must have repaired this on the board and forgot to update the graphic.)
Sleeper

thats cool man, although it stumped me for a while.

I still can't get it going though.
Is the schematic defiantly correct?
That last stage before the meter is doing something screwy.
I've been over and over the pcb and can't sort it

I found a second error on the layout: R2 does not connect to the junction of R5, R11F, D1 etc. I just jumpered the left sides of R2 and R5 on top of the board. With these two fixes the board works really well. However, the oscillator circuit operates at 50kHz instead of 100kHz. This is consistent with other notes on the circuit from Creative accompanying the same schematic that I found somewhere else on line (BAMA? if I remember correctly).

I'm still working on the meter scale in Inkscape, getting there...

Thanks Sleeper for doing the PCB artwork! It would have taken me ages to cobble it together otherwise, my veroboard and layout skills are still, er, under development. 

John

Fantastic! 
must have been over that thing a hundred times and never spotted that.
Lucky as i was just about to give up order an Atlas tester.
I'll have another go in the morning.

Thanks John and thank you sleeper for your hard work. ;D

Hey you guys are good. Those are exactly the mistakes I had indeed fixed on my board.  I've edited the layout image above, so everything should be working fine now. 

You may want to do a little editing/drawing on the board layout.
I have a footprint for some pretty large trimpots (Something that I had laying around)
you mayy have to fill in just a bit to work with smaller trimmers. 

Otherwise let's call this new layout checked.

Kelly

Otherwise let's call this new layout checked.

Click to expand...

I concur.
Mines working now. Havent got the meter scale right yet tho. Calibration wise have you guys just measured say a 10ohm resistor, 50ohm resistor to check its giving the correct reading?


Also do either of you guys have a nice max esr chart i can stick to the front of my meter, i've found a few but there not very pretty....

Hey Clunky,
I did that too (measuring a few resistors) as well as testing some very old capacitors that I was pretty sure were dried out (and in fact a few of them were).  I also tested some brand new low esr specified caps and they were indeed low esr. I guess maybe one of the supergenius types here might have a better way to test this.
Seems good for now.
I'm out of town, but I found (and maybe slightly altered) a meter scale.  I probably have the drawing on my home computers. I'll post it when I get back.
Kelly

just built the esr meter and it dont work ? is schematic a good one and the pcb is it correct ?????thkx larry

larry,
check the drawing that's been revised along side the pdf package.
I think they were both changed, but that was a while ago,
maybe the one in the pdf is unrevised?
look at JDR's post just in case and you should get it working.