Electronics and Communication Engineering - Automatic Control Systems

Assertion (A): An on off controller gives rise to oscillation of the output between two limits.

Reason (R): Location of a pair of poles on jω axis gives rise to self sustained oscillations in the output.

1. It is of non-minimum phase behaviour
2. It normally exists in thermal, hydraulic and pneumatic systems
3. It has an excessive phase lag with no attenuation at high frequency

1. If any root of characteristic equation has a positive real part the impulse response is unbounded and system is unstable.
2. If all the roots of a characteristic equation have negative real parts, the impulse response decays to zero.
3. If one or more non-repeated roots of characteristic equation are on jω axis impulse response is bounded but the system is unstable.