Basics of Nyquist Plot
Trending Questions
Q. The Nyquist plot for the open-loop transfer function G(s) of a unity negative feedback system is shown in the figure, if G(s) has no pole in the right-half of s-plane, the number of roots of the system characteristic equation in the right-half of s-plane is
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1180468/original_2.a1.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1180468/original_2.a1.png)
- 0
- 1
- 2
- 3
Q. The Nyquist plot of a loop transfer function G(jω)H(jω) of a system encloses the (−1, 0) point. The gain margin of the system is
- less than zero
- zero
- greater than zero
- infinity
Q. The number and direction of encirclements around the point −1+j0 in the complex plane by the Nyquist plot of
G(s)=1−s4+2sis
G(s)=1−s4+2sis
- zero
- one, anti-clockwise
- one, clockwise
- two, clockwise
Q.
The number of times the Nyquist plot of
G(s)=s−1s+1
will encircle the origin clockwise is
- 1
Q. Which of the following is the transfer function of a system having the Nyquist plot shown in figure below?
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1146539/original_cs61.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1146539/original_cs61.png)
- Ks(s+2)2(s+5)
- Ks2(s+2)(s+5)
- K(s+1)s2(s+2)(s+5)
- K(s+1)(s+3)s2(s+2)(s+5)
Q. The pole-zero map of a rational function G(s) is shown below. When the closed counter r is mapped into the G(s)−plane, then the mapping encircles.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1185746/original_27.a1.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1185746/original_27.a1.png)
- the point −1+j0 of the G(s)−plane once in the counter-clockwise direction
- the origin of the G(s)−plane once in the clockwise direction
- the origin of the G(s)−plane once in the counter clockwise direction
- the point −1+j0 of the G(s)−plane once in the clockwise direction
Q. Nyquist plots of two fucntions G1(s) and G2(s) are shown in figure.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1149608/original_5.a1.png)
Nyquist plot of the product of G1(s) and G2(s) is
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1149608/original_5.a1.png)
Nyquist plot of the product of G1(s) and G2(s) is
Q.
Consider the statndard negative feedback configuration with
G(s)=s2+0.2s+100s2−0.2s+100 and H(s)=12.
The number of clockwise encirclements of (-1, 0) in the Nyquist plot of the Loop transfer-function G(s) H(s) is
- 0
Q. For the transfer function G(jω)=5+jω, the corresponding Nyquist plot for positive frequency has the form