[Open_electroporator] ADC measuring shows need for redo of kvboard layout

[Nathan McCorkle]

On Dec 28, 2017 7:26 AM, "John Griessen" <john at cibolo.com> wrote:

On 12/27/2017 09:58 PM, Nathan McCorkle wrote:

> Are you saying out of 3.1V range, 2400kV on the HV side of the pulser
> produces only 0.08V on the ADC?
>

Yes.  When you have a 30k Ohm cuvette resistance.  Cuvette resistance can
be much lower if larger
loads or salty suspension/solution is used, but we are not aiming for that
power level yet.


Ok, I see you're talking about current-to-voltage measurement re: 0.08v

The volt divider is 1/800 (from memory), so if 2400V in, the volts seen by
the ADC would be:
3V.  very close to the top end when using a 3.1V regulator as planned now.


Can we change that to around 1/2600 to get better range? We're easily
blowing >2400V way out of range, no chance we're going to do any failure
analysis with that, and I don't think there's a need for sub-volt
resolution.


Besides running at lower volts, the only way to get more bit resolution for
current measuring


Sorry, wasn't concerned with current measurement at all in my last
comments, I think your idea of keeping it within power availability
range/envelope makes sense.
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