[Open_electroporator] Timers, PWM, low-level MCU setup

[John Griessen]

On 03/24/2017 01:10 AM, Nathan McCorkle wrote:
> It should be the yellow label in the images, as the HV was the yellow trace
>
>
>
>     What are your probe test points in the circuit?
>
>
> Pics here:
> Http://m.imgur.com/a/Xug6u <http://m.imgur.com/a/Xug6u>
>
> Also I sent a hand-drawn schematic a week or two ago illustrating the probe, 33kohm, and 1GOhm

OK.  The 3/22/2017 attachments have a first image of scope screen with 1V/div, 1ms/div showing a rise to the non-spiky part of the 
wave being 2 volts at the second step, then plateaued.  A push pull cycle is coming about every 900 microseconds in this photo.

 From using your divider with a gigaohm resistor in series with the probe you get a volt division ratio.  It could be that your
probe plus the scope input resistance is 1meg, then the division ratio would be 1:1000.
Could be that probe has a 10megohm input resistance, then the division ratio would be 1:100.

Probably your probe/scope has 1 meg R, because that matches my results from 2/24/2017, which I have copied here.
That shot was done with a calibrated 100:1 probe, 5V/div.  So each of its divisions is 500V, and after about 3
switcher push-pull cycles coming every 800 usecs, the output is up to 1300V.

So, most conditions are the same:
You got 2 cycles til plateau, I got 5 til plateau.
You got ~2kV plateau, I got 1600V plateau calibrated, probe compensated +/- 5% accuracy.

The culture_shock v0.1 seems to have survived shipping.  Seems to have improved, or your unit is different, or your probe is off 
some.  I was in such a hurry to get units out the door I did not make a record of each ones pulse output by a photo running the 
same program -- I just noted that they worked and packed them in boxes and envelopes so I could get going on the trip I'm on.

What is the model number of probe you are using?  Is it a 1 meg Ohm?  The Rigol scope is probably 1 meg ohm input resistance. 
Probes depend on the scope input R being a known quantity to work right.

John Griessen
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