Question

Routh test cannot be used to test the stability of a control system containing:

• A. Controller
• B. Transportation lag
• C. Final control element
• D. Controller and control element

Hint:

For systems with time delays, use Nyquist or root locus methods for stability analysis.

Answer 1

The Correct Option is B

The Routh-Hurwitz stability criterion cannot handle systems with pure time delays (transportation lag) because these introduce non-rational terms into the characteristic equation.