What I wasn't clear (as novice) was the following
1. Threshold is set 2/3 Vref and 1/3vref. But is lower threshold not zero?
2. Why is tap taken from vin to positive terminal of op-amp and why is it half of VIN through voltage divider?
3. When MOSFET is ON, discharge timing is R4C1 and charging time is R1C1 (according to me). Does it really produce triangle wave?
4. Inverting Integrator always produces voltage output of opposite polarity, but threshold is positive, why?
5. In the frequency output equation, I do not find role of R4?
Sorry for by silly and basic questions?