Timeline for Tuning a potential sensor using a source-follower MOSFET
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Aug 20, 2018 at 0:35 | comment | added | Mowgli | Exactly, but as I mentioned, there's reports of setups tracking the source voltage rather than the current; the low cost aspect is an important part of this project and ideally I'm looking for a way to extract the information using a reasonably cheap component (24-bit ADC)... So that would force me to operate in sub-saturation regime, right? | |
| Aug 19, 2018 at 22:02 | comment | added | Henry Crun | Once fet is in saturation (on the flat of the curve), VDS does not matter. IDS is being set by VGS. VGS changes-> IDS changes. You are measuring IDS. | |
| Aug 19, 2018 at 20:28 | comment | added | Mowgli | The thing that bugs me is that if we create a virtual ground then wouldn't Vds be stable too (and therefore there would be no signal)? I just have a hard time picturing what would be left to measure, if not a current. I was under the impression that operating in the triode region would at least change the resistance of the device, which would be easily measurable. | |
| Aug 19, 2018 at 20:23 | comment | added | Mowgli | Yes the choice of the gate polarity with respect to analyte charges makes sense; so here if I want to detect anions I could go for a p-type enhancement MOSFET or an n-type depletion mosfet, I suppose. | |
| Aug 18, 2018 at 21:41 | history | answered | Henry Crun | CC BY-SA 4.0 |