[Open_electroporator] China transformer coming along!

[Nathan McCorkle]

Very cool! For PCBs will you be able to use OSHPark? Around here, I
usually get my boards in a week or two max... the only thing they
don't do is guarantee impedance or anything like that, which I think
is really only required for high-speed stuff (and maybe also very
sensitive analog diff-pair stuff???)... OSHPark just sent out a notice
that they're having an open-house, I was thinking I might go to check
it out.

On Fri, Sep 23, 2016 at 9:33 AM, John Griessen <john at cibolo.com> wrote:
> I've had some back and forth with TMK Transformers
> http://tmktransformers.com of Dongguan, north of Shenzen China.
> The first bobbin I chose was not available so I found another with lots of
> searching and it is available and
> TMK has done a test assembly.  The attached photos show how my first choice
> of fat 23 gauge wire would not fit,
> but 25 gauge does.  TMK has my DHL inbound shipper number, so when they have
> core halves glued together for this they will send.
>
> There are some others that might do samples, but I told them it would have
> to be by China Post or Taiwan Post and
> they have quieted down.  It seems as thought there is a buyer frenzy for
> this kind of thing where the first to get enough details to make a sample
> locks in business.  I'm not certain how to interpret one comment by TMK, but
> it might mean their price promise for 10k volumes is no longer good.
> Probably everything needs renegotiating frequently, and by walk-away tactics
> with bids from
> competition, and no trying to get samples for less than express delivery
> methods, or you've shown your hand and lose that "poker hand".
>
> The new bobbin I chose is a surface mount type like before, and the whole
> thing is a little smaller, and can come in
> tape and reel packaging for low cost assembly -- valuable when this becomes
> a going low cost
> product and sells more than hobby volumes.
>
> So now I "get back to it" making schematic symbols and pcb footprints for a
> prototype board with
> ARM micro running micropython, connectors for power from a wall wart supply,
> microUSB, spike suppression,
> driver FETs, transformer, voltage doubler, safety interlock cutoff.
>
> John
>
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-- 
-Nathan