Effect of feedback on stability, Electrical Engineering

Assignment Help:

Q. Effect of feedback on stability?

Let us consider the direct transfer function of the unstable first-order system of Figure (a). The transfer function is given by

396_Effect of feedback on stability.png

where p = d/dt is the differential operator. If a unit-step function is applied as the input quantity E, the output becomes

1886_Effect of feedback on stability1.png

for which the corresponding time solution is given by

c(t) = K(1 - et/τ)

which is clearly unstable, since the response increases without limit as time passes. By placing a negative feedback path H around the direct transfer function, as shown in Figure (b), the closed-loop transfer function is then

1979_Effect of feedback on stability2.png

where cf(t) denotes response with feedback. The system is now clearly stable with aK > τ . Thus, the insertion of feedback causes the unstable direct transmission system of Figure (a) to become stable. Such a technique is often used to stabilize space rockets and vehicles, which are inherently unstable because of their large length-to-diameter ratios. Note that the direct transfer function of Equation has a pole located in the right half p-plane at p = 1/τ , whereas the pole of the closed-loop transfer function of Equation with aK > τ is located in the left half p-plane.


Related Discussions:- Effect of feedback on stability

Forward and reverse battery bias, Forward and Reverse battery bias In ...

Forward and Reverse battery bias In diagram below(a) the battery is arranged that is why the negative terminal supplies electrons to the N-type material. These types of electr

Various characterstics of a dc shunt generator. , Q.   Draw the various cha...

Q.   Draw the various characterstics of a DC shunt generator and explain critical resistance.   Sol.  Following are three most important characterstics or curves of a d.

Switching characteristics - power semiconductor devices, Switching charact...

Switching characteristics When  a positive signal  is applied GTO starts  conducting before  initiation of  conduction anode  current  is zero  and anode to cathode voltage Va

Perform octal subtraction, Q. Do as directed. a) Hexadecimal addition: ...

Q. Do as directed. a) Hexadecimal addition: 101 + ABC b) (43.25) 10-(89.75) 10 using 1's Complement c) Octal Subtraction 123-777 d) (123)6 + (435)6 = ( ? )6 e) ABC

Draw a block diagramfor a 2-to-4 decoder, Q. Draw a block diagramfor a 2-to...

Q. Draw a block diagramfor a 2-to-4 decoder. Obtain the truth table, and develop a logic diagram.

Find the value of the induced emf, Q. A six-pole, double-layer dc armature ...

Q. A six-pole, double-layer dc armature winding in 28 slots has five turns per coil. If the field flux is 0.025 Wb per pole and the speed of the rotor is 1200 r/min, find the value

Instrument, Differentiate between dual beam and dual trace oscilloscope

Differentiate between dual beam and dual trace oscilloscope

Find the value of noncoherent source, If E b /N 0 = 20 in a coherent ASK s...

If E b /N 0 = 20 in a coherent ASK system, find the value of Eb/N0 that is needed in a noncoherent ASK system to yield the same value of Pe as the coherent system.

Illustrate the photo-conductive cell, Illustrate in detail digital encoders...

Illustrate in detail digital encoders. Illustrate the following with their application: Photo-conductive cell Photo-voltaic cell

Construct a truth table and get the minimum sop expression, Q. For the logi...

Q. For the logic circuit of Figure, construct a truth table and obtain the minimum SOP expression.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd