The Schmitt trigger circuit shown in the figure below uses Zener diode with Vd = 0.7 V. If the threshold voltage V1 is zero and hysteresis voltage VH = 0.2 V, then what is R1/R2 and VR? [Figure description: An op-amp Schmitt trigger. Vin is applied to the inverting (-) input. The non-inverting (+) input node (voltage V1) is connected through resistor R1 to the op-amp output V0, and through resistor R2 to a reference voltage VR. The output V0 is clamped to ground by two back-to-back Zener diodes (each labelled Vz).]
- A. R1/R2 = 67 and VR = 0.15 V
- B. R1/R2 = 67 and VR = -0.15 V
- C. R1/R2 = 66 and VR = -0.10 V
- D. R1/R2 = 66 and VR = -0.15 V