GATE 2022 IN – Question 64
The switch is initially closed. It opens at $t=0$ and remains open. The time when comparator output $V_{out}$ becomes LOW is ______ ms (three decimal places).
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Show answer and explanation
Correct answer: 0.365 to 0.369
Explanation
Initial capacitor voltage is 5×5k/(1k+5k)=25/6 V. Threshold is 5×400k/(600k+400k)=2 V. Discharge time constant is 5k×0.1 μF=0.5 ms. Crossing time is 0.5ln[(25/6)/2]=**0.367 ms**.