Topic: Control Systems
Signal flow diagram of following analog computer circuit is
- A. Graph with nodes A, s^2y, sy, y and feedbacks 2, 3, 4
- B. Graph with nodes A, s^2y, sy, y and feedbacks -2, 3, 4
- C. Graph with nodes A, s^2y, sy, y and input -7
- D. Graph with nodes A, -s^2y, -sy, y
Answer: C. Graph with nodes A, s^2y, sy, y and input -7
Explanation: In an analog computer circuit, standard operational amplifiers configured as integrators inherently invert the signal (transfer function $-1/s$). Therefore, mapping the block diagram to a Signal Flow Graph (SFG) requires careful accounting of these inversions to maintain the correct characteristic equation $d^2y/dt^2 = 7x + 2 d^2y/dt^2 - 3 dy/dt - 4y$ which is typically normalized in SFG form as depicted in standard option mappings.