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Electrical Engineering

Bipolar Junction Transistor

A silicon n-p-n bipolar junction transistor is designed with emitter, base and collector doping levels of 10^19cm, 10^15cm and 5*10^17cm, respectively. Assuming the intrinsic carrier concentration (ni) in silicon to be 10^10cm, calculate the Fermi Energy, Ef, relative to the intrinsic energy scale clearly to show the relative po

Block Diagram Reduction

First Problem: 1. Find TY/R. 2. Find TU/d Second Problem: a) Find TY/R for the following system.

Knowledge About Control Systems

Consider a transient response of a control system as shown in the attached figure. Choose which system description matches this response. a) DC gain 2, pole at -2, -3, -4. b) DC gain 2, pole at -1-j4.4, -1+j4.4. c) DC gain 1, pole at -1-j4.4, -1+j4.4. d) DC gain 1, pole at -10. e) DC gain 2, pole at -10, -2, zero at +5.

Proportional-Rate Feedback Control

Consider the block diagram in the attached figure Q3.1, describing the process under Proportional-Rate Feedback control. 1) Find a closed loop system transfer function in terms of controller gains, Kp, Kd. 2) Find the value gains Kp,Kd such that the resulting Percent Overshoot of the closed loop step response will be equal

Matched Filter Theory

Find the impulse response of a filter matched to the signal in the attached problem. 1 Find the impulse response of a filter matched to the signal . Assume

Control Systems: PID Controller

Which one of the following statements regarding the operation of a PID controller is definately false? - Higher Proportional gains improve steady-state error performance. - If the system operates in a noisy industrial environment, PID control is recommended - Higher Integral gains may result in the system becoming unstable

Controller Configurations in Control Systems

Consider the responses of a closed loop system under several types of control. Choose the controller configuration that would result in the response following the dashed line trace on the plot. - Proportional Control - Lead Control - Proportional + Derivative Control - Lag Control - PID Control

Control Systems: Operation of a PID

Which one of the following statement regarding to operation of a PID is true? - Lower proportional gains improve steady state error performance - Derivative action tends to slow down system rise time - Higher derivative gains filter out noise - High integral gains may saturate controller output and cause the windup effect -

Control Systems - System Output

Please supply steps to correct answer: For a CLOSED LOOP unit feedback control system, if reference (R) is eqaul to 5 units, and forward path Gain (G) is equal to 10, then the system output (Y) must be: (a) 50 (b) 4.54 (c) 5 (d) 10/11 (e) 0.454

Compute the Transfer Equation

The questions are for the equation: y"(t) + 6y'(t) + 34y(t) = 2x'(t) + 11x(t) a) Compute the transfer equation Y(s)/X(s). b) Compute the response of the system to the input x(t)=e^(-2t) u(t) assuming no initial stored energy. c) Compute the response of the system to the input x(t)=4t^2 * e^(-6t) u(t).

Using the Ruth Hurwitz Criterion

Question: Find the values of k for the system in part a) and the values of alpha for part b). Please view the attachment file to see the full questions for parts a) and b).

Nyquist Analysis Bode Plots

Given the Bode plot of open loop L(s)=..., (i) Make a sketch of the Nyquist diagram and determine the stability of the closed loop system with negative feedback.(ii)If the system is unstable... (See attachment for full questions)

Substituting equation explanation

This is perhaps more of a mathematical question nonetheless, I'm unsure how (cant seem to arrive at the result) substituting equation 3-27 into 3-23 results in 3-28. Please see the attachment.

Bode and Nyquist Diagram and Root Locus

Roughly sketch the Bode diagram, and hence the complete Nyquist diagram for: {see attached} Proportional control of the plant {see attached} in a standard negative feedback 2DOF structure (with an ideal sensor) is to be investigated {see attachment for questions}.

Control Systems - Unity Feedback Loop, Nyquist Contour, Routh-Hurwitz Analysis

A process has a transfer function: {see attached} and is included in a unity feedback loop with a proportional controller Kp in a feedforward branch of the control loop. (a) Sketch a Nyquist contour for this system (b) Apply the Nyquist stability criterion to find a suitable range of K for stable closed loop system behaviour.

Closed Loops and Root Locus

Consider the root locus for ... (*see attachments for function and diagram) i) Graphically, find the gain required to give dominant closed loop poles with ... (*see attachment for function) ii) For the above value of gain, find natural frequency and hence sketch the expected reference to output step response, assuming that the

Data link question

In order to delimit messages from a stream of bits being exchanged on a data link, a sender marks the beginning and end of each message with a control flag. In order to prevent the receiver from inadvertently detecting the end of a message when a pattern in the data matches the control flag, the sender stuffs extra bits or chara

Control Systems, Amplifier Gain, Natural Frequency, Root Locus

Please consider the attached motor control system. (i) Find the characteristic equation of the closed loop system, and find the amplifier gain K1 so that the natural frequency of the system is {see attachment} (ii) Suppose that K2 = 1. Sketch the root locus of the closed loop system poles for {see attachment} (iii) For what v

Negative Gain Root Locus

Consider a negative gain root locus for L (s) = k (s-1)/[s(s^2 + 4s + 8)] with a scale of 20mm = 1 unit. i. Graphically, find the gain required to give dominant closed loop poles with zeta = 0.5. ii. For the above value of gain, find natural frequency and hence sketch the expected reference to output step response, assuming

Block diagram in feedback control system form

I attached a Word document with a circuit: a) Draw a block diagram of the circuit in feedback control system form. b) Derive an expression for Io in terms of Vi and the system parameters Av, Ro, RL, and Rf. c) How should the system be designed to make Io independent of RL? What is the approximate expression for Io in terms

Erlang Problem Described

1. A company needs to provide sufficient private trunks between two switches to accommodate 90% of call attempts among employees during the busy hour. Assume that there will be 560 callers at random times during that hour, and that call duration averages 3 minutes. Employees are instructed to attempt to call using a trunk; if bl

Rayleigh PDF

Show that the average (mean), mean-square, and median values of the Rayleigh PDF for amplitude are given by the equations listed in the attachment.

PI Controller Design

Please see attachment for full question on PI controller proportional and integral to the given plant. The inverse Nichols chart mentioned in the question is also attached for convenience.

Input Tone in to an Amplifier

Consider a single input tone, such that: Vo = ko + k1*Vin + k2* Vin^2 + k3*Vin^3 +.... Let Vin = cos(wt). Now if a tone is put into an amplifier, and its amplitude is increased by 1.5dB, how much will the amplitude of the third order products increase in dB? Using the third order term only of the transfer polynomial, prove this