microelectronics by sedra and smith 8th edition chapter 7 Archives

gebuch

Asked: March 4, 2022In: microelectronics

For the follower circuit, let transistor Q1 have β = 50 and transistor Q2 have β = 100, and neglect the effect for ro. Use VBE = 0,7V.

(a) Find the dc emitter currents of Q1 and Q2. Also, find the dc voltages VB1 and VB2.(b) If a load resistance RL = 1 kΩ is connected to the output terminal, find the voltage gain from the base to the emitter of ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

D 7.138 A CE amplifier has a midband voltage gain of = 100 V/V, a lower 3-dB frequency fL = 100 Hz, and a higher 3-dB frequency fH = 500 kHz. In Chapter 10 we will learn that connecting a resistance Re in the emitter of the BJT results in lowering fL and raising fH by the factor (1 + gmRe). If the BJT is biased at IC = 1 mA, find Re that will result in fH at least equal to 2 MHz. What will the new values of fL and AM be?

D 7.138 A CE amplifier has a midband voltage gain of = 100 V/V, a lower 3-dB frequency fL = 100 Hz, and a higher 3-dB frequency fH = 500 kHz. In Chapter 10 we will learn that connecting a ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

*7.137 For the follower circuit in Fig. P7.137, let transistor Q1 have β =50 and transistor Q2 have β =100, and neglect the effect of ro. Use VBE = 0.7 V. (a) Find the dc emitter currents of Q1 and Q2. Also, find the dc voltages VB1 and VB2. (b) If a load resistance RL =1 kΩ is connected to the output terminal, find the voltage gain from the base to the emitter of Q2, vo/vb2, and find the input resistance Rib2 looking into the base of Q2. (Hint: Consider Q2 as an emitter follower fed by a voltage vb2 at its base.) (c) Replacing Q2 with its input resistance Rib2 found in (b), analyze the circuit of emitter follower Q1 to determine its input resistance Rin and the gain from its base to its emitter, ve1/vb1. (d) If the circuit is fed with a source having a 100- kΩ resistance, find the transmission to the base of Q1, vb1/vsig. (e) Find the overall voltage gain vo/vsig.

*7.137 For the follower circuit in Fig. P7.137, let transistor Q1 have β =50 and transistor Q2 have β =100, and neglect the effect of ro. Use VBE = 0.7 V. (a) Find the dc emitter currents of Q1 and Q2. ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

**7.136 For the circuit in Fig. P7.136, called a boot-strapped follower: (a) Find the dc emitter current and gm, re, and rπ. Use β = 100. (b) Replace the BJT with its T model (neglecting ro), and analyze the circuit to determine the input resistance Rin and the voltage gain vo/vsig. (c) Repeat (b) for the case when capacitor CB is open-circuited. Compare the results with those obtained in (b) to find the advantages of bootstrapping.

**7.136 For the circuit in Fig. P7.136, called a boot-strapped follower: (a) Find the dc emitter current and gm, re, and rπ. Use β = 100. (b) Replace the BJT with its T model (neglecting ro), and analyze the circuit to determine ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

7.135 For the emitter follower in Fig. P7.135, the signal source is directly coupled to the transistor base. If the dc component of vsig is zero, find the dc emitter current. Assume β =100. Neglecting ro, find Rin, the voltage gain vo/vsig, the current gain io/ii, and the output resistance Rout.

7.135 For the emitter follower in Fig. P7.135, the signal source is directly coupled to the transistor base. If the dc component of vsig is zero, find the dc emitter current. Assume β =100. Neglecting ro, find Rin, the voltage ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

7.134 For the emitter-follower circuit shown in Fig. P7.134, the BJT used is specified to have β values in the range of 80 to 180 (a distressing situation for the circuit designer).

venkyelectrical

Asked: January 16, 2022In: microelectronics

D 7.133 For the circuit in Fig. P7.133, find the value of the bias current I that results in Rin = Rsig. Also, find the voltage gain vo/vsig. Assume that the source provides a small signal vsig and that β =100.

D 7.133 For the circuit in Fig. P7.133, find the value of the bias current I that results in Rin = Rsig. Also, find the voltage gain vo/vsig. Assume that the source provides a small signal vsig and that β ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

7.132 The BJT in the circuit of Fig. P7.132 has β = 100. (a) Find the dc collector current and the dc voltage at the collector. (b) Replacing the transistor with its T model, draw the small-signal equivalent circuit of the amplifier. Analyze the resulting circuit to determine the voltage gain vo/vi.

7.132 The BJT in the circuit of Fig. P7.132 has β = 100. (a) Find the dc collector current and the dc voltage at the collector. (b) Replacing the transistor with its T model, draw the small-signal equivalent circuit of the amplifier. ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

7.131 In the circuit of Fig. P7.131, the BJT is biased with a constant-current source, and vsig is a small sine-wave signal. Find Rin and the gain vo/vsig. Assume β = 100. If the amplitude of the signal vbe is to be limited to 5 mV, what is the largest signal at the input? What is the corresponding signal at the output?

7.131 In the circuit of Fig. P7.131, the BJT is biased with a constant-current source, and vsig is a small sine-wave signal. Find Rin and the gain vo/vsig. Assume β = 100. If the amplitude of the signal vbe is ...

venkyelectrical

Asked: January 16, 2022In: microelectronics

7.130 The amplifier of Fig. P7.130 consists of two identical common-emitter amplifiers connected in cascade. Observe that the input resistance of the second stage, Rin2, constitutes the load resistance of the first stage. (a) For VCC = 15 V, R1 = 100 kΩ, R2 = 47 kΩ, RE = 3.9 kΩ, RC = 6.8 kΩ, and β =100, determine the dc collector current and dc collector voltage of each transistor. (b) Draw the small-signal equivalent circuit of the entire amplifier and give the values of all its components. (c) Find Rin1 and vb1/vsig for Rsig = 5 kΩ. (d) Find Rin2 and vb2/vb1. (e) For RL =2 kΩ, find vo/vb2. (f) Find the overall voltage gain vo/vsig.

7.130 The amplifier of Fig. P7.130 consists of two identical common-emitter amplifiers connected in cascade. Observe that the input resistance of the second stage, Rin2, constitutes the load resistance of the first stage. (a) For VCC = 15 V, R1 = ...

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