In the single-phase voltage controller circuit shown in figure below, for what range of triggering angle (α), the output voltage (Vo) is not controllable? [Figure description: An AC source in series with an anti-parallel pair of thyristors (two SCRs connected in opposite directions) feeding a series RL load of 50 Ω resistor and a j50 Ω inductor; the output voltage Vo is measured across the load.]
- A. 0° < α < 45°
- B. 45° < α < 135°
- C. 90° < α < 180°
- D. 135° < α < 180°
Answer: A. 0° < α < 45°
Explanation: For load impedance angle φ = 45°, conduction control is effective in the range 0° < α < 45°.