Tag: ESR Meter

ESR Meter – PCB And Project files.

Posted by on December 4, 2010

These are the project files for the ESR Meter,

I included the schematic and the PCB layout with all the necessary layers. I used “non standard” tools for this one. I reckon there’s no need for gerber files here since I never intended anything but 1 PCB out and I don’t have a CNC mill anyway (feel free to send me one!).

You may download the files from here: esrmeter_project_files.

A list of materials is also included in one of the schematic files.

You may also be interested in reading the following posts:



As I mentioned before this is simply a project I found out there, I wanted a PCB for it so I quickly designed one and I’m now sharing it for those who may be interested in building one. There’s enough material covering the inner workings, theory, etc. in the links found here.

I don’t know exactly who designed the circuit to begin with so that’s a mystery I’ve yet to resolve.

The PCB was revised and built so I know it all works, but if you find a problem don’t hesitate to let me know about it.

Cheers.

ESR Meter – What went wrong.

Posted by on November 6, 2010


Current PCB layout for the ESR Meter

Continuing with the ESR project, I’d like to enumerate the various issues I encountered during layout design, fabrication and finishing of the project.

I believe some people only show their “good side” and bury deep down each and every failure they suffered, however you don’t learn from winning and that’s why I thought it would be a good idea to write this.

These are some of the problems diagnosed during troubleshooting in no particular order:

  1. PCB Layout error, first revision circuit had a trace that was mistakenly connected to another component, this rendered the detector phase useless.
  2. Bad ceramic capacitor, the 470pF was damaged. Replaced with two 1nF in series to approximate the value.
  3. The transformer displayed losses at high frequencies, it was replaced with another transformer. (I still worry about the output level, it’s way under 100mV)
  4. Negative supply “biasing” potentiometer had one of the wires broken by the PCB end, most likely due to the amount of handling involved during the troubleshooting phase: always hotglue your wires!!
  5. Power supply wasn’t providing enough voltage for the opamp used, turns out 5v input is a no-go for TL082 due to manufacturing tolerances, etc. I had to go for 12V. The final unit uses 13.8V — I would like to go up to 15V but that calls for a different regulator.
  6. Deflection issues due to the 100uA meter, feedback gain was changed and a potentiometer was added for convenience.
  7. One of the test leads had a high resistance due to severed wires by the connector, this was a cheap DMM set of leads and I regret using them!
  8. The only TL082s I had were in SMD packages, so I had to etch a dip adapter board!
  9. My PCB layout was lost, well — the source file at least, this meant I had to redraw the entire layout from scratch, based on screenshots.
  10. Several placement and power issues during the last phase of the project were encountered, all of which have been fixed ever since — Although I’m not entirely happy with the placement of the potentiometers, they’re at a slight angle and this means their values will shift due to the slight pressure they’re under.

So, I wasn’t kidding when I said this wasn’t a simple project! — Probably the most problematic one thus far. However I didn’t give up and I could probably say I succeeded.

Special thanks to Lee and everyone in ##electronics @ freenode  for the invaluable help and support!

Have fun!
Cheers.

ESR Meter Update

Posted by on November 1, 2010

The sausage paws are playing with the pots. Turns out the power supply is not good enough for our purposes.

I decided to build the ESR meter I talked about a post or two ago, I must say it wasn’t as simple as I thought it would be, mainly due to several mistakes and problems I encountered, thankfully though one of the authors of the ESR meter gave me a hand troubleshooting the circuit, so I was able to finish that stage of the project.

Now that it’s functional, I’ve been working on the enclosure!

I decided to build a benchtop unit and later-on a portable one, mainly because I don’t need a portable ESR meter right now and I had the enclosure, transformer, etc. all assembled already.

More…

Which came first, the chicken or the egg?

Posted by on October 4, 2010

I’ve been searching for a nice, simple and trusty ESR meter circuit all weekend long, while filtering out the bad sites I landed on these two projects:

http://members.multimania.co.uk/leeedavison/misc/esr/
http://www.ludens.cl/Electron/esr/esr.html

Hmm… I suspect neither designed the circuit but rather, adapted it from a printed magazine or similar source. I’d just like some clarification on the matter.

As I was researching the input protection from the first link, I also came up with this: http://members.shaw.ca/swstuff/esrmeter.html

Now, is this flattery or just plain ol’ “let’s copy this and hope no one finds out”. If you’re taking concepts or ideas from someone else, at least mention them – heck, discuss it with them and actually put the conversation online if both parties agree, or collaborate with each other to come up with a better solution!. More…