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I have seen graphics cards with a melted up molex power connector on them.

Thats the problem with pulling large currents thru many paralleled connectors, when they start to go, you end up with one of them taking all the current and they melt up. The leads on power supplied arent usually the best quality and I dont know what the insertion rating on those molex plugs are, but with the third party ones on PSUs often being a tight fir you have to rock them around so much that I expect that is when the damage to the contacts occurs.
My motherboard (Gigabyte Extreme EX58) has a partially damaged main ATX power supply molex connector due to a low quality power supply: months of bad contact partially melted the plastic and partially corroded two 5V contacts.

However, to reach the point of combustion something must have really gone wrong here... Perhaps flammable wiring insulation? Flammable X/Y caps or transformer insulation on the Power Supply?
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Thank you for ideas. I looked at the options.

AR9331 at first seemed great option but unfortunately it has no hardware float support. We might need it for some custom software. It's my fault, I forgot mentioning it, I'll update the post.

I also found http://www.acmesystems.it/arietta and they claim to have completely open Linux software. There's just one quirk - Arietta has microSD instead of flash memory.
Is Atmel ARM platform really that open-source friendly? In that case we could use it on our custom designed platform with flash eMMC.

I have seen a similar product to ours implemented on Freescale MPC8314E:
http://www.mouser.com/ds/2/161/MPC8314EEC-51265.pdf
but I'm not sure how open Freescale is and how do they treat small startup companies - is it possible to buy their SoCs in quantities less than 1000?
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Blog Specific / Re: eevBLAB #8 - Meet Dave
« Last post by VK5RC on Today at 08:48:07 PM »
Doesn't the apprentice get the water cooled light bulb from stores dept? ;D
All the best Dave2.
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Test Equipment / Re: Geller Labs SVR and SVR-T
« Last post by Andreas on Today at 08:47:37 PM »
But what I noticed is that a close by WiFi and Cell Phone activity will have a massive influence on the data. Much more than I would have expected, even is the cell phone is 2 to 3 m away.

Hello,

did you already try a blocking capacitor (10-100nF) at the output of the SVR-Reference. (near pin 4+6 of the AD587).
I always try to place one (as long as the reference does not oscillate) to reduce RFI effects.

With best regards

Andreas


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Whilst I like the DCA75 in its mobile format, I believe PEAK have massively enhanced it with the PC connectivity. Such connectivity has enabled them to use some pretty tidy looking software to not only present the data in a large format, but also provide the curve tracing display. IMHO any competing product would also need such a capability to be considered in the same league. There is only so much you can do with a small format LCD display.

Aurora
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Other Equipment & Products / Re: Safety glasses
« Last post by SeanB on Today at 08:43:33 PM »
Opthalmic surgeon's office, and him there with a needle digging into the numbed cornea. bit hard to keep still with the wide open eye seeing this massive sharp point coming closer and closer. A year later I get a call at midnight from a friend to come fetch him at the hospital, as he cannot drive with one eye bandaged up and the other dilated from the eye drops as well.
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Projects, Designs, and Technical Stuff / Re: 2 Way DC motor School Project
« Last post by Ian.M on Today at 08:42:07 PM »
Get rid of the 2K2 resistors.  They'd only allow slightly over 2mA to flow which wouldn't be enough to turn any motor you are likely to encounter.

+1 for using the reversing switch schematic from LukeW's second link.
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Blog Specific / Re: EEVblog #678 - What is a PCB Spark Gap?
« Last post by SeanB on Today at 08:39:53 PM »
Or you could just use a gas discharge tube that likely will have both higher surge capacity, higher current handling and more importantly a much more predictable breakover voltage that does not change with ambient air pressure, temperature, composition and humidity.
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During my experiments I held a metal PC slot cover near the transmitter. It got hot pretty quick.

Probably you had desent amount of magnetic flux througth it  ;)

Tried to make some kind of feasibility study of my concept and used also this MIT Inductance and Magnetic Energy guide, than  wrote a few lines of code to compute mutual inductance as well as other self-inductance of each coils: transmiter 3m in diameter put on room ground and small 1inch receiver and numbers doesn't look great at 1MHz  1 meter above ground 3m diamater transmiter coil :-\
Code: [Select]
wpt: freq: 1.000 [MHz]
wpt: w0: 6283185.307 [rad/s]

wpt: r1: 1.500 [m]
wpt: r2: 0.013 [m]
wpt: z: 1.250 [m]

wpt: wire: A: 2.500 [mm^2]
wpt: copper resistivity: p: 1.724e-08 [ohm * m]

wpt: n1: 3
wpt: r1: 1.500 [m]
wpt: l1: 0.011 [m]

wpt: n2: 9
wpt: r2: 0.013 [m]
wpt: l2: 0.032 [m]

wpt: R1: 0.195 [Ohm] wire length: 28.274 [m] diameter: 1.784 [mm]
wpt: L1: 7468.071 [uH] C1: 3.392 [pF]

wpt: R2: 0.005 [Ohm] wire length: 0.718 [m] diameter: 1.784 [mm]
wpt: L2: 1.606 [uH] C2: 15771.959 [pF]

wpt: M: 0.096228767 [nH]
wpt: k: 0.000000879

wpt: RL: 0.005 [Ohm]
wpt: n: 0.009462686 [%]
I used 2.5 mm2 copper wire and only 3 turns on transmiter and 9 in receiver.
However, when recalulated at 27.120 MHz also around 1 meter above tramsiter coil it looks much better:
Code: [Select]
wpt: freq: 27.120 [MHz]
wpt: w0: 170399985.531 [rad/s]

wpt: r1: 1.500 [m]
wpt: r2: 0.013 [m]
wpt: z: 1.250 [m]

wpt: wire: A: 2.500 [mm^2]
wpt: copper resistivity: p: 1.724e-08 [ohm * m]

wpt: n1: 3
wpt: r1: 1.500 [m]
wpt: l1: 0.011 [m]

wpt: n2: 9
wpt: r2: 0.013 [m]
wpt: l2: 0.032 [m]

wpt: R1: 0.195 [Ohm] wire length: 28.274 [m] diameter: 1.784 [mm]
wpt: L1: 7468.071 [uH] C1: 0.005 [pF]

wpt: R2: 0.005 [Ohm] wire length: 0.718 [m] diameter: 1.784 [mm]
wpt: L2: 1.606 [uH] C2: 21.444 [pF]

wpt: M: 0.096228767 [nH]
wpt: k: 0.000000879

wpt: RL: 0.006 [Ohm]
wpt: n: 6.133360781 [%]
However, didn't calculated Q factor yet, only guessing from this MIT guide that lowering R in receiver coil will improove this Q factor.
When we change receiver coil to 0.5 in diameter numbers are much better even at 1MHz  >:D

BTW: According to this http://en.wikipedia.org/wiki/ISM_band and this thread http://www.eevblog.com/forum/projects/6-78-mhz-ism-band-worldwide/
6.780 MHz is marked as subject to local acceptance , while  27.120 MHz worldwide , however it require more sophisticated equipment and faster switching.

Anyway it is interesting what happends at 1MHz, 6.790 Mhz and 13.560 MHz or 27.120 MHz-higher frequency.
Huge coil means that coupling coeficient will be small if we put inside small loop relative to much bigger transmiter, so probably inductive heating will not be a problem, but much bigger to notice any energy transfer effects at all  between big and small coil.
Now its time to see more youtube videos while, we know how mutual inductance is affected by coils geometry and its distance between each other used in this kind of experiments.
Quick calulation shows, that distance between coils makes a huge difference, so no ssupprise what we see on tricky youtube WPT demos ???

Update: Another story is transmiter power limits even on those worldwide ISM band radio frequency, so 30W+ isn't too much?
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Microcontrollers & FPGA's / Re: Atmel versus NXP
« Last post by nctnico on Today at 08:36:47 PM »
If you want to use Atmel be sure to spell out every little detail in the datasheet. I'm not using Atmel devices anymore due to too many problems with their devices.
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