On Wed, Jul 16, 2014 at 6:16 AM, Erik Christiansen <dva...@internode.on.net> wrote:
> > > If the usage is there, it may well be worth the price, although a useful > but basic instrument can readily be put together. The circuits which are > thrown up by a "ESR meter circuit" google vary noticeably in complexity, > but are mostly pretty cheap to build. Since it only takes a 0.1 ohm and > 1 ohm resistor or similar from the junkbox to calibrate them, some of > them pretty much have to be good enough for identifying dud > electrolytics, and even those which are marginal. > > I've only glanced through this article, but it doesn't look too bad, and > provides a good background for anyone needing an ESR primer: > > http://kakopa.com/ESR_meter/ > > But it admits to being a bit insensitive at the low end. This one talks > about 1 ohm being 90% of full scale. That would just about do me until I > found perfection: > > http://members.shaw.ca/swstuff/esrmeter.html > > There are also circuits with transformers between oscillator and the > test capacitor, to lower the source impedance. That would be needed for > low ESR caps, I think. I'm tempted to add a cap and a step-down > transformer to an existing design which is otherwise appealing. I bought > a slab of Siemens RM4 ferrite core and bobbin sets for a song the other > day. Now I have a use for one of them. > > Here's one with better low ESR measurement potential: > > http://www.ludens.cl/Electron/esr/esr.html > > Who's found a better one? > > The thing is to know whether the circuit needs Low ESR caps, or ordinary > ones will do. If they are in a SMPS, or the power section of a VFD, then > bank on it. > > Erik > Erik, Check out the link I posted earlier. It's a pretty good one, and I've had mine now for a couple of years. This is the one that was designed by Bob Parker a few years back, and has been updated a bit cosmetically. mark ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
