Concept explainers
Consider the BJT feedback circuit in Figure
(a)
The value of the voltage gain for the given values of
Answer to Problem 12.11TYU
The value of the voltage gain for
Explanation of Solution
Given:
The given diagram is shown in Figure 1
Figure 1
Calculation:
Apply KVL to the base emitter terminal of the circuit.
The value of the Thevenin equivalent voltage is calculated as,
The value of the Thevenin equivalent resistance is calculated as,
The emitter current is calculated as,
The value of the base current is calculated as,
The value of the collector current is calculated as,
The value of the small signal resistance is given by,
The expression to determine the voltage gain of the amplifier is calculated as,
The value of the input resistance is calculated as,
The value of the small signal voltage gain is calculated as,
By miller theorem the value of the resistance
For
From DC analysis the value of the base current is calculated as,
The value of the transconductance is calculated as,
The value of voltage gain is calculated as,
The value of the input resistance is calculated as,
The voltage gain is calculated as,
Conclusion:
Therefore, the value of the voltage gain for
(b)
The value of the voltage gain for the given values of
Answer to Problem 12.11TYU
The value of the voltage gain for
Explanation of Solution
Given:
Calculation:
Consider
The value of the base current is calculated as,
The value of the collector current is calculated as,
The value of the transconductance is calculated as,
The value of the voltage gain is calculated as,
The value of the voltage gain is calculated as,
Solve further as,
For
By miller theorem the value of the resistance
For
The value of voltage gain is calculated as,
The value of the input resistance is calculated as,
The voltage gain is calculated as,
Conclusion:
Therefore, the value of the voltage gain for
(c)
The percent change in the magnitude of the voltage gain from part (a) to (b).
Answer to Problem 12.11TYU
The percent change in the magnitude for
Explanation of Solution
Given:
Calculation:
The change in the magnitude of the voltage gain for
The change in the magnitude of the voltage gain for
Conclusion:
Therefore, the percent change in the magnitude for
Want to see more full solutions like this?
Chapter 12 Solutions
Microelectronics: Circuit Analysis and Design
- 2-) The AC equivalent of a feedback amplifier circuit is given in the figure on the right. (Hfe100, Va = ∞, Ic1 = 15 mA, Ic2 = 5mA and Ic3 = 5 mA) a) State the type of feedback used in the circuit, explaining the reason. b) Draw the small signal equivalent of the amplifier circuit. c) Calculate the value of β for the feedback by drawing the β circuit. d) Find the Avf = Vo / Vs closed loop gain of this circuit. e) Find the Rif and Rof values.arrow_forward(a) Calculate the sensitivity of the closed-loop input resistance of the series-shunt feedback amplifier with respect to changes in open-loop gain A:SRinA = A/ Rin ∂Rin/ ∂A (b) Use this formula to estimate the percentage change in closed-loop input resistance if the openloop gain A changes by 10 percent for an amplifier with A = 94 dB and β = 0.01. (c) Calculate the sensitivity of the closed-loop output resistance of the series-shunt feedback amplifier with respect to changes in open-loop gain A:SRout A = A /Rout ∂Rout /∂A (d) Use this formula to estimate the percentage changeinclosed-loopoutputresistanceiftheopenloop gain A changes by 10 percent for an amplifier with A =100 dB and β =0.01.arrow_forwardConsider a system with an open loop transfer function defined by Determine the expression of the phase advance corrector that must be used to have a phase margin greater than 40º while limiting the static error in position to 1/6.arrow_forward
- An open loop Transfer function of unity feedback system is given by G(s)= 1/(s+2)^2 The closed loop transfer function will have poles atarrow_forwardA. If the forward gain is 5 and feedback gain is 1, determine the close-loop gain of a negative feedback amplifier. answer: B. For a Wien-bridge oscillator (as presented in the lecture), if the feedback resistor has a value of 10-kohm, determine the value of Ri (in kilo-ohm). answer:arrow_forward2. Design a unity gain inverting summing amplifier that will output the sum of two input voltages. Use a feedback resistor of 2.5 Kohms.arrow_forward
- Discuss the difference between the current series negative feedback amplifier and voltage shunt feedback amplifier in terms of output impedance, input impedance, voltage gain, bandwidth, distortion and noise.arrow_forwardGiven the following amplifier with feedback circuits A, B, C and D shown below... Assuming circuits A and C share the same feedback topology, determine their feedback topology. Assuming circuits B and D share the same feedback topology, determine their feedback topology. Determine whether each circuit utilizes positive or negative feedback. Note: For questions asking for feedback topology, answers can only be shunt-shunt, shunt-series, series-series or series-shuntarrow_forwardA unity feedback system with open-loop transfer function given as:?(?) = ??. ?(? + ?)(? + ?)(? + ??)without affecting its operating point (−1.54 ∓ ??2.66) appreciably a- Design a suitable compensator to drive the step response error to zero.b- Design a suitable compensator to reduce step error by factor of 5.arrow_forward
- Discuss the distinction between open-loop gain and closed-loop gain.arrow_forwardConsider a unity negative feedback system with loop transfer function shown in Figure where L(s)=GcG(s)=K(s2+6s+1)(s2+5s+1)L(s)=GcG(s)=K(s2+6s+1)(s2+5s+1) Determine the value of K for which the closed-loop system is stable.arrow_forwarddescribe the expression of sensitivity of C.L.T.F. wrt. feedback gain.arrow_forward
- Power System Analysis and Design (MindTap Course ...Electrical EngineeringISBN:9781305632134Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. SarmaPublisher:Cengage Learning