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rickman <gnuarm@gmail.com>: Mar 06 02:04AM -0500 On 3/6/2017 1:56 AM, Foxs Mercantile wrote:   > It is. But some people have difficulty accepting anything more > complicated than a light bulb, or more expensive than a pack of > cigarettes.   You mean like thermal cameras?   --   Rick C

John Larkin <jjlarkin@highlandtechnology.com>: Mar 05 07:44AM -0800 On Sun, 5 Mar 2017 14:48:51 -0000 (UTC), Cursitor Doom   >https://www.sparkfun.com/products/11005   >Replace the existing connector with a BNC, add a bit of series resistance >and you have a *very* cheap current probe for your scope.   I have a clamp-on ammeter that pretty much does that, although it just indicates amps, and doesn't allow waveform snooping. 60 Hz waveforms aren't terribly interesting.   My real problem with current measurement is DC, on PC boards. We want to know how much current, say, an FPGA is using. Sometimes I include current shunts in a layout, but sometimes I don't.   One can use existing switcher inductors as current shunts. I wish I had a PCB trace current probe, but that's probably not posssible. You can measure millivolt and microvolt drops across traces and vias.         --   John Larkin Highland Technology, Inc   lunatic fringe electronics

Cursitor Doom <curd@notformail.com>: Mar 05 04:18PM On Sun, 05 Mar 2017 07:44:18 -0800, John Larkin wrote:   > I have a clamp-on ammeter that pretty much does that, although it just > indicates amps, and doesn't allow waveform snooping. 60 Hz waveforms > aren't terribly interesting.   Indeed they're not. But your meter is presumably *only* designed for use at 60Hz, I would imagine. Hook it up to a 100Hz signal and you'll see nothing at all in all probability. ;-)   > One can use existing switcher inductors as current shunts. I wish I had > a PCB trace current probe, but that's probably not posssible. You can > measure millivolt and microvolt drops across traces and vias.   Do they even exist? That would be amazing but no doubt *way* beyond what I can justify to splash out on as a mere hobbyist.

John Larkin <jjlarkin@highlandtechnology.com>: Mar 05 01:37PM -0800 On Sun, 5 Mar 2017 15:07:41 -0600, Foxs Mercantile <jdangus@att.net> wrote:   >They do make special current probes specifically for doing traces >on a PC board. without cutting traces or requiring a loop of wire. ><http://www.power-mag.com/pdf/feature_pdf/1327592496_TTI_Layout_1.pdf>   Looks expensive, and I'd guess not very accurate.     --   John Larkin Highland Technology, Inc   lunatic fringe electronics

Foxs Mercantile <jdangus@att.net>: Mar 05 05:41PM -0600 On 3/5/2017 3:37 PM, John Larkin wrote: > Looks expensive, and I'd guess not very accurate.   <http://www.aimtti.us/product-category/current-probes/aim-i-prober-520> It is expensive. At $795 for the basic probe. Data sheet: <http://resources.aimtti.com/datasheets/prec-iprober520-5p.pdf> Instruction manual: <http://resources.aimtti.com/manuals/I-prober_Instruction_Manual-Iss5.pdf>       -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com

piglet <erichpwagner@hotmail.com>: Mar 06 11:01AM > The old HP current probe was a great debugging tool.   +1 I'd love an HP-547A   piglet

Cursitor Doom <curd@notformail.com>: Mar 06 11:27AM On Mon, 06 Mar 2017 00:56:56 -0600, Foxs Mercantile wrote:   > It is. But some people have difficulty accepting anything more > complicated than a light bulb, or more expensive than a pack of > cigarettes.   For the *real* cheapskates out there, there's this alternative:   http://www.ebay.com/itm/100A-SCT-013-000-Non-invasive-AC-current-sensor- Split-Core-Transformer-YH-/201842524936? hash=item2efec08308:g:vm8AAOSwCGVX3BYF   Claims to be able to handle up to 100A!

John Larkin <jjlarkin@highlandtechnology.com>: Mar 06 08:43AM -0800 On Mon, 6 Mar 2017 00:56:56 -0600, Foxs Mercantile <jdangus@att.net> wrote:     >It is. But some people have difficulty accepting anything more >complicated than a light bulb, or more expensive than a pack of >cigarettes.   It's not hard to figure where current is going: just measure voltage drops. What's sometimes difficult is quantifying it.   Just now we're laying out a 10-layer board with two ground planes and three power planes. There are 22 power supplies. Most of the power distribution will be interestingly-shaped interleaved pours, not traces, on various layers.   That magnetic gadget would be hopelessly confused. Multiple currents and various return paths would make it useless.   My favorite tool for tracing unusual current flows is my Flir E45 thermal imager. It cost $12,000.   We just demoed a cool new thermal imager, mounted on a nice little stand, with its own display and also USB interfaced for pics or movies. They're going to let us keep it.     --   John Larkin Highland Technology, Inc   lunatic fringe electronics

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Mar 05 09:55PM "Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message news:3_OdnerXncqr1SHFnZ2dnUU7-W2dnZ2d@earthlink.com... > pfjw@aol.com wrote: >> file:///C:/Users/Peter/Downloads/corrosion_of_silver_plated_copper_conductor.pdf   > Come on, Peter. Another link to your C: drive?   Couldn't open that - maybe someone formatted it.......................

"pfjw@aol.com" <pfjw@aol.com>: Mar 06 04:06AM -0800 Forgot to add:   a) NOT due to the silver. b) Sulphur and sulphur compounds are not involved at all.   Peter Wieck Melrose Park, PA

N_Cook <diverse@tcp.co.uk>: Mar 06 04:19PM > The thickness of the coating - at least several molecules - is plenty wide enough, if you will excuse the expression.   > Peter Wieck > Melrose Park, PA   Any connection with metalisation creep ? I associate with silver plating of the segments of ceramic resonators, the thin segment gets metal migrating over the edge and going ohmic and failure of RF/IF stages.

"pfjw@aol.com" <pfjw@aol.com>: Mar 06 08:37AM -0800 On Monday, 6 March 2017 11:20:06 UTC-5, N_Cook wrote:   > Any connection with metalisation creep ? I associate with silver plating > of the segments of ceramic resonators, the thin segment gets metal > migrating over the edge and going ohmic and failure of RF/IF stages.   Absolutely a connection. Silver-Mica disease in vintage radios is one obvious manifestation of such creep.   A very simple explanation here:   http://www.gdsiswitches.com/silver-migration.html   As silver is an excellent conductor, it takes very little for a current path to develop.   Although this is not absolutely specific to your question - the phenomenon and mechanisms are the same.   It is interesting to note that what is common to all these various discussions around silver and how it affects most electronics does not involve Sulphur, or actual corrosion of the silver itself.   Peter Wieck Melrose Park, PA

vjp2.at@at.BioStrategist.dot.dot.com: Mar 05 08:01PM Got a notice about retirement of copper   Most important will dialup modems and fax work?   A while back almost had to because squirrel ate my line   My line comes in from back of house but power from front. But my phone lines branch out form middle of basement where laundry & hVAC are and there is plenty power. Grammar school chum who became electrician told me I should tell them to install fiber there. (He said some may be ornery but I would be right torequest it.)   Now new notice says I can have OPTIONAL backup power and they use D batts. Maybe they have changed?   Other than tell them to put it midhouse, do I have anything else to worry about?   - = - Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist http://www.panix.com/~vjp2/vasos.htm ---{Nothing herein constitutes advice. Everything fully disclaimed.}--- [Homeland Security means private firearms not lazy obstructive guards] [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

Phil Allison <pallison49@gmail.com>: Mar 05 11:18PM -0800 > >"** Fraid that ref does not mention the spec.   > You bullshitting fucking idiot. "   > Bullshit, it says 500 fucking volts.   ** Wrong spec - you bullshitting imbecile.   In most tube books, "plate volts" = "plate supply" voltage !!! The **actual plate voltage** swings up to nearly double in operation, single ended or push pull. The 2.4kV figure I posted is the max, zero current plate voltage that is guaranteed. IOW, the insulation rating.   In an operating push-pull stage, plate voltage reaches max on a tube when plate the current is near zero. The opposite is true too, plate voltage reaches minimum when plate current is max on that tube.   EL34s are *speced* to operate with a 750V supply, so the pate voltage on one EL34 in a PP pair is nearly 1500V when the voltage on the other is less than 60V.   All I am saying is that 6L6s can do the same and commercial examples exist that prove the point.   You know absolutely NOTHING about tube output stages.   FYI:   Don't fret too hard, hardly anyone does.       .... Phil

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