ELEC 4509 Assignment 1 Dec 2021

A source with equivalent noise temperature Te = 1000 K is followed by a cascade of three amplifiers shown in Table 1.0. Assume a bandwidth is 60 kHz, evaluate the overall noise factor and noise figure of the cascade. In order to get better performance of the amplifier system, you may try to re-arrange the amplifier units. Please prove and justify which arrangement is the best to be chosen.

Given the diferrential amplifier with a constant-current source at the emitter (instead of the resistor RE) (a) Determine Io, Ie1, and Ie2.For DC Analysis: Ie1=Ie2 due to symmetry(b) Determine hie1 and hie2.(c) Determine the differential gains Ads (for single-ended) and Add (for double ended).

For the given amplifier circuit, asnwer the following question: a) For R1= 12 kΩ, R2= 10 kΩ, RE= 1 kΩ, RC = 1.2 kΩ, determine the following dc parameters: VB, VE, IE, and VC . (assume stiff voltage divider) b) For r’e = 5.5 Ω, R1= 12 kΩ, R2= 10 kΩ, RE= 1 kΩ, RC = 1.2 kΩ, RL = 7.5 kΩ, RS = 500 Ω, determine the input resistance at the base ( Rin(base) ), the total input resistance ( Rin(tot) ), voltage gain (Av) ,and attenaution. c) Assume that the overall voltage gain A’v = 120, the dc collector voltage VC = 6.3 V, and Vin = 15 mV rms. Determine the ac collector voltage (Vc) , then draw the total collector voltage waveform d) For r’e = 5.5 Ω, RE= 1 kΩ, RC = 1.2 kΩ, RL = 7.5 kΩ, determine the voltage gain if C2 is removed. Explain the effect of removing C2 on gain stability.

Question No. 1: A circuit based on an amplifier shown in Fig.1 is installed in locationwhere the temperature varies largely. This variation produces unwanted changes in theoutput signal. Being electronic engineer suggest a suitable change in the circuit so theoutput should be stable as well as amplified. Justify your answer by analyzing thecircuit.Discuss what will be the effect of suggested changes if the BJT is replaced by anyFET.

For the amplifier as shown, VDD = 12 V, VSS = 12 V, ISS = 20 μA, and RD = 820 kΩ. Assume IDSS = 1 mA and VP = +2 V. (a) What are the output voltages υo for the amplifier for υ1 = 0V and υ1 = 20 mV? (b) What is the maximum permissible value of υs?

Three identical amplifiers are connected in cascade as shown. Each amplifier has Av = −30 and fH = 33.3 kHz. What are the gain and bandwidth of the composite threestage amplifier?

the transistor in the circuit above has gm=0.11mS and ro=33Kohm. Given the following condition: R1=770Kohm, R2=890Kohm, RD=5.4Kohm, R3=20Kohm, R6=6.9Kohm, Rsig=2Kohm, determine the input impedance of the amplifier in Kohm.

What is the voltage gain of the amplifier shown if VCC = VEE = 5 V,                  I1 = 500 μA, R1 = 20 Mμ, I2 = 100 μA, R2 = 10 Mμ, βo = 80, VA = 75 V,              Kp = 5 mA/V2, and VT P = −1 V?

Help me with the following multiple choices questions: 1) In amplifier design, the Quiescent point represents   A. Zero signal values of IC and VCE B. The magnitude of signal C. None of the above D. Values of IC and VCE when signal is applied   2.The saturation current of a transistor used in an fixed-bias circuit is _ ______ its value used in an emitter-stabilized or voltage-divider bias circuit for the same values of RC.  A. None of the above B. Less than C. The same as D. More than   3. A negative feedback results in _______ A. increased voltage gain B. None of the above C. decreased voltage gain D. oscillation in the circuit   4

3. What is the overall gain or attenuation of the combination formed by cascading the circuits described in Problems 1 and 2? 4. Three amplifiers with gains of 15, 22, and 7 are cascaded; the input voltage is 120 μV. What are the gain and the output voltages of each stage?

A common-collector amplifier is being driven from a source having a resistance of 250 Ω. (a) Estimate the output resistance of this amplifier if the transistor has βo = 150, VA = 50 V, and Ic = 10 mA.(b) Repeat for Ic = |m|.

A single-transistor amplifier is needed that has a gain of approximately 0 dB and an input resistance of 20 MΩ with a load resistor of 20 kΩ. What isthe preferred choice of amplifier configuration, and why did you make this selection?

Given the diferrential amplifier with a constant-current source at the emitter (instead of the resistor RE),Assume Q1, Q2, and Q3 are identical transistors with β=hfe=100 and VBE=0.7V. (a) Determine the common-mode gains Acs (for single-ended) and Acd (for double ended).For AC analysis: The constant current source has an infinite equivalent resistance.(b) Determine the common-mode rejection ratio CMRR for single-ended output.(c) Determine the common-mode rejection ratio CMRR for double-ended output.

Find the voltage gain Av, output voltage vo, and output current io for the amplifier as shown ifR1 = 3 k , R2 = 43 k , and vi = +0.1 V.

The following Common Emitter (C.E.) amplifier is biased with a currentsource I. It has β = 100, VA = ∞, VT = 25mV, and rπ = 25kΩ. Draw the small signal equivalent circuit including the Hybrid-π with the βIb currentsource model. Label the input (Rin), output (Rout), and base (Rib) resistances. Find Rib, Rin, Rout, and the voltage gain (vo/vsig).

Compute for the values of the components for a Common Base Amplifier Circuit if Vin is between 5mV to10mV and has a voltage gain of 10+ V and Current Gain of 1A to 2A.

(a) A source follower is drawn as a two-port as shoen. Calculate Gm and Gr for this amplifier in terms of the small-signal parameters. Compare the two results. (b) What are the values of Gm and Gr if RG = 1 MΩ, RD = 50 kΩ,        gm = 500 μS, and ro = 450 kμ?

Given values - β is 100Vth =0.4 Calculate the gain of the following amplifiers. Use appropriate approximations where applicable.[Gain is defined as the ratio of the output signal to the input signal which can be a voltage or current.]

(a) What are the Q-points of the transistors in the amplifier as shown if I1 =500 μA, R1 =1MΩ, I2 = 500 μA, R2 = 1 MΩ, and VCC = VEE = 7.5 V. Use βo = 80, VA = 75 V, Kp = 5 mA/V2, and VT P = −1 V. (b) What are the differentialmode voltage gain and input resistance and output resistance of the amplifier? (See Sec. 15.2.3.)

Design a difference amplifier shown in the following figure to meet the following criteria: vo = 2vb - 5va. The resistance seen by the signal source vb is 750 kΩ, and the resistance seen by the signal source va is 16 kΩ when the output voltage vo is zero. (Figure 1) Specify the value of Ra Specify the value of Rb Specift the value of Rc Specify the value of Rd

A single-transistor amplifier is needed that has a gain of approximately 66 dB and an input resistance of 250 kΩ. What is the preferred choice of amplifierconfiguration, and why did you make this selection?

Given r_e = 10 Ω, β = 200, A_v = -160, and A_i = 19 for the collector-feedback network shown below, determine a) R_C; b) R_F; and, c) V_CC .

Choose the correct answer to the two points 2-The ac emitter resistance of an emitter followera-Equal the dc emitter resistance .b-Is larger than the load resistance .c-Is β times smaller than the load resistance. d-Is usually less than the load resistance.3-A common-base amplifier can be used when a-Matching low to high impedance.b-A voltage gain without a current gain is required. c-A high- frequency amplifier is needed.d-All of the above.

What is the voltage gain for the small signall differential amplifier showed in the image. The other is grounded. rπ = 3.5kohms. ICQ = 1.5mA (in case is needed). Beta = 200. Note: for this differential amplifier there is only one input signal at the base of the transistor, the other base of the transistor is grounded.

Answer these questions. Explain Phase inversion of Common Emitter Amplifier. How Common Base Amplifier differs from Common Emitter and Common Collector Amplifier? Calculate Voltage Gain if RC = 150 Ω and RL = 200 Ω, IE = 1.5mA

A common-source amplifier with a drain resistance, RD = 4.7 k Ω, is powered using a10 V power supply. Assuming that the transconductance, gm, is 520 μA/V, the voltage gain of the amplifier  is closest to:

Given: The transistor has a scale current of 1.5x10-14 A and VCEsat = 0.2 V. It is operating at 300°K. Fill up the following table and approximate the gain of this amplifier by computing for Δvo/ΔvI as vi is varied from 10 to 30 mV.

What are the unity-gain frequency and slew rate of the bipolar amplifier as shown if I1 = 100 μA, I2 = 400 μA, and CC = 10 pF? (b) If I1 = 300 μA, I2 = 350 μA, and CC = 10 pF?

find small signal gain Av. of the amplifier from Vin to Vout assuming that Rc = 5Kohms Rs = 0 and Rl = infinity