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I was wondering how CMOS-based capacitive electrodes might be designed (e.g. in this article I stumbled on). It seems to me, that it would make sense to capacitively couple the input of the transistor to the signal you were trying to measure.

But how would one go from one bit of information (one transistor conducting or not conducting as a result of coupling) to a more robust representation of the signal with an amplitude described by multiple bits (i.e. some quantized representation of the signal in, say, 16 bits). Is it possible that the transistors are each designed with different threshold values to represent the various bits that are the amplitude of the signal at that point in time? Is that even practical, or is there some other method that might be employed to achieve that affect?

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    \$\begingroup\$ Throwing away all the chaff and trying to get to the bottom line of your question, are you actually asking how an analogue signal can be converted to a digital signal? \$\endgroup\$ – Andy aka Aug 14 '17 at 16:28
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    \$\begingroup\$ Probably do something like discharge the gate and see how long it takes to charge to the point the transistor conducts using the capacitively coupled signal. The article is short on details, and long on useless text. I didn't follow any of the links to see if more details are available. \$\endgroup\$ – JRE Aug 14 '17 at 16:33
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    \$\begingroup\$ @Andy aka Oh, wow, somehow I didn't think of that... You're right, I just described an ADC, but it didn't really click in my mind until you left that comment. That's my fault, I think I know where to look now though, thanks \$\endgroup\$ – Scorch Aug 14 '17 at 16:33

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