Search found 5 matches

by Luns
07 Apr 2019, 05:16
Forum: Workshop
Topic: CommonSense: matrix LCR meter with a HID interface
Replies: 572
Views: 211537

Re: [Done] CommonSense controller - better capsense!

5888 has 4 OpAmps, 4 comparators and 4 programmable blocks that can be told to be TIAs. I simply haven't seen a single reason to use them. I wasn't able to find the TIAs earlier, but it turns out that was because I was fiddling with the CSSK design which was uses a 5267. I don't understand why it l...
by Luns
05 Apr 2019, 19:25
Forum: Workshop
Topic: CommonSense: matrix LCR meter with a HID interface
Replies: 572
Views: 211537

Re: [Done] CommonSense controller - better capsense!

Luns wrote:
02 Apr 2019, 06:31
This being the case, I'm wondering, why not put an op-amp follower between the mux and the ADC?
I guess one consideration would be the limited bandwidth of the op-amp: it may not be fast enough to follow the mux output in time for the ADC sampler.
by Luns
05 Apr 2019, 05:26
Forum: Workshop
Topic: CommonSense: matrix LCR meter with a HID interface
Replies: 572
Views: 211537

Re: [Done] CommonSense controller - better capsense!

My gut feeling is that the IBM/Xwhatsit arrangement may perform a little better: the sensing side of things is of course more sensitive to things, and a larger 24-input mux is sure to have more parasitics. Just turn on your scope and see for yourself. I'm not forcing anybody to use any particular c...
by Luns
02 Apr 2019, 07:19
Forum: Workshop
Topic: Alternate ways of sensing teh Fs...
Replies: 13
Views: 4143

Re:

Disclaimer - I am not an expert, this is my reading and understanding of the scope. I'm completely prepared to be wrong. In fact I'm really very good at being wrong, it should be my vocation. Every strobe actually consists of eight 5V pulses over ~700us period. https://deskthority.net/download/file...
by Luns
02 Apr 2019, 06:31
Forum: Workshop
Topic: CommonSense: matrix LCR meter with a HID interface
Replies: 572
Views: 211537

Re: [Done] CommonSense controller - better capsense!

I just tuned in recently, so I'm still getting up to speed on where everything is; please forgive me for any pieces I'm missing. So far, I've had a look at threads about xwhatsit, dph, and commonsense. I see some merits and shortcomings to each of them, and perhaps there's some room to improve. I've...

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