[Open_electroporator] Fwd: [GeigerCounterEnthusiasts] Re: HEI X-ray tube driver news and update

John Griessen john at industromatic.com
Mon Mar 10 03:23:39 UTC 2014


On 03/09/2014 07:39 PM, Nathan McCorkle wrote:
> John G,
> what do you think about this? It uses automotive coils which are said to be rated up to 100kV, and the author of the circuit says
> the time constant and voltage would be easy to add adjustment to.
>
>  From looking at the two schematics it seems to only lack a mains isolation transformer, but the silicon is still hooked up to
> rectified-wall-AC voltage... is that a concern, or would optos provide isolation for that part of the circuit to remove user-risk?
>

Uh... the only way to reduce-not-remove user risk with HV + power is mechanical and controlsystem-wise.
Isolation from building ground is not so important with HV + power -- the voltage will do
it's thing and find a conducting path no matter that.  It is possible to reduce danger somewhat
by reducing the output current, (and thus power), capability, but this X-ray power level is beyond that.




> There is a primary current setting pot that determines at what current
> point the IGBT opens to fire the spark. Varying the applied DC voltage
> and that pot will vary the voltage of the pulse.
>
> Web page is here:
>
> http://www.neon-john.com/Nuke/X-ray/HEI_driver/HEI_driver.htm



  Rockauto.com has them for $11.30 when I checked last week

Good price for a HV coil and more, but they can be had for less in the wake of the obsolescence of
CRT TVs.  These are high quality auto parts though, so good to experiment with.
And they have more engineered/tested electronics than a flyback transformer -- they have IGBTs
-- tough transistors for throwing the switch to make a spark in lieu of a relay with arcing contacts
as in the model T.  I have a model T coil in the attic that would make a dandy electroporator also.
But how to make it easy to manufacture as a kit product is rather important if you want it to
outflow and make easy priced genetic engineering tools available.


http://www.neon-john.com/Nuke/X-ray/HEI_driver/HEI_driver.htm
"NOTE: This is a line-operated device and as such the entire PCB is at line potential. "

Oh, we will want our own PC board, not something that low down.  Some way to keep the power to
the minimum needed, and inside plastic covers when it is released to arc or just quietly
zap pores in cell walls.

John
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