I have a staircase generator circuit with a Mosfet connected to capacitor 2. The input of the capacitor is connected to a comparator and I wish for the Mosfet to cutoff when the output of the comparator is high. The comparator is connected to a sine wave generator enter image description here The waveform I want to achieve is shown below. enter image description here I am having problems achieving this, when the Mosfet is disconnected as above, the wave form I get is this. enter image description here So the blue staircase wave is working as intended albeit no resetting. However the moment I connect it the staircase waveform is affected with some weird fluttering at the beginning and then it not resetting the staircase anyway enter image description here. I have confirmed that with a manual switch the staircase resets as needed however I cannot get the transistor to work as intended.

enter image description here

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    \$\begingroup\$ This question looks extremely familiar... You didn't happen to delete this question and ask it again, did you? \$\endgroup\$ – KingDuken Apr 25 '18 at 15:17
  • \$\begingroup\$ I deleted it yesterday because I realised I misunderstood the question, and what I was asking for was not possible or at more difficult than the scope of the question. Unfortunately only realised after wasting a lot of time. \$\endgroup\$ – Intent Filters Apr 25 '18 at 16:20

It cannot work like that. The mofet discharges the capacitor just down to the value where VStaircase goes a bit lower than Vsine, not down to zero as you wish. It's a negative feedback, that it should do.

To act as you wish you need to trigger a short impulse that fully opens the mosfet for a short time.

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