[Open_electroporator] bare boards back from fab, assembled, testing OK.

[Nathan McCorkle]

very cool! good to hear.
I have been soaking up the summer while the dry days last, so no progress
on lab work. It seems we really need to get the ADC feedback working for
any customer use. Sadly I have not done any reading on the MCU recently to
help their either.



On Aug 24, 2017 3:52 PM, "John Griessen" <john at cibolo.com> wrote:

> This morning I had an assembly error that was hard to find because of
> assuming it was something.
> What was keeping the 20V DC from getting to more than 0.25 volts was
> schottky protection diodes in reversed.
>
> Culture shock version 0.2 has a mistake and we'll be on to v0.3 right away
> -- the schematic symbol and footprint for
> my protection diodes that go in parallel to the transistors have terminal
> numbers and names anode cathode 1 and 2...
>
> One or the other is reversed, so I will be changing the footprint or
> symbol to fix it.
>
> Meanwhile, this circuit drives the push and pull transistors hard, and
> they perform to move energy
> per pulse.  The volts can really shoot up.  This design protects the main
> transistors from transients
> that can kill them, and isolates the microcontroller outputs from the main
> switching going on for reliability.
>
> With the DC at 9V I was getting a plateau at 2300V,
> and with a lab supply set at 17V to the switcher transformer windings I
> had to reduce the number
> and spread them out because after the first four or so pulses work charge
> through the stages, the
> volts shoot up about 700 volts per push pull pair of pulses.
>
> So, maybe I'll be sending 12V wall warts now...  More soon.  This could be
> good news for future uses with
> animal cells --  more power and more volts available.
>
> --
> John
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