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Electronic Devices and Circuit Theory

Robert Boylestad, Louis Nashelsky

Chapter 5

BJT AC Analysis - all with Video Answers

Educators

Chapter Questions

01:09

Problem 1

a. What is the expected amplification of a BJT transistor amplifier if the de supply is set to zero volts?
b. What will happen to the output ac signal if the dc level is insufficient? Sketch the effect on the waveform.
c. What is the conversion efficiency of an amplifier in which the effective value of the current through a $2.2-\mathrm{k} \Omega$ load is $5 \mathrm{~mA}$ and the drain on the $18-\mathrm{V}$ de supply is $3.8 \mathrm{~mA}$ ?

Jacob Shpiece
Jacob Shpiece
Numerade Educator
01:13

Problem 2

Can you think of an analogy that would explain the importance of the dc level on the resulting ac gain?

Averell Hause
Averell Hause
Carnegie Mellon University
00:12

Problem 3

If a transistor amplifier has more than one dic source, can the superposition theorem be applied to obtain the response of each dc source and algebraically add the results?

Manish Kumar
Manish Kumar
Numerade Educator
04:38

Problem 4

What is the reactance of a $10-\mu \mathrm{F}$ capacitor at a frequency of $1 \mathrm{kHz}$ ? For networks in which the resistor levels are typically in the kilohm range, is it a good assumption to use the short-circuit equivalence for the conditions just described? How about at $100 \mathrm{kHz}$ ?

Zulfiqar Ali
Zulfiqar Ali
Numerade Educator
01:11

Problem 5

Given the common-base configuration of Fig. 150 , sketch the ac equivalent using the notation for the transistor model appearing in Fig. $7 .$

Dominador Tan
Dominador Tan
Numerade Educator
03:26

Problem 6

a. Given an Early voltage of $V_{A}=100 \mathrm{~V}$, determine $r_{o}$ if $V_{C E_{e}}=8 \mathrm{~V}$ and $I_{C_{Q}}=4 \mathrm{~mA}$.
b. Using the results of part (a), find the change in $I_{C}$ for a change in $V_{C E}$ of $6 \mathrm{~V}$ at the same $Q$ -point as part (a).

Kajal Gautam
Kajal Gautam
Numerade Educator
01:06

Problem 7

For the common-base configuration of Fig. 18, an ac signal of $10 \mathrm{mV}$ is applied, resulting in an ac emitter current of $0.5 \mathrm{~mA}$. If $\alpha=0.980$, determine:
a. $Z_{i}$
b. $V_{o}$ if $R_{L}=1.2 \mathrm{k} \Omega$.
c. $A_{v}=V_{d} / V_{i}$.
d. $Z_{o}$ with $r_{o}=\infty \Omega$.
e. $A_{i}=I_{o} / I_{i}$
f. $I_{b}$

Narayan Hari
Narayan Hari
Numerade Educator
02:29

Problem 8

Using the model of Fig. 16, determine the following for a common-emitter amplifier if $\beta=80, I_{E}(\mathrm{dc})=2 \mathrm{~mA}$, and $r_{o}=40 \mathrm{k} \Omega$
a. $Z_{i}$
b. $I_{b}$.
c. $A_{i}=I_{o} / I_{i}=I_{L} / I_{b}$ if $R_{L}=1.2 \mathrm{k} \Omega$.
d. $A_{v}$ if $R_{L}=1.2 \mathrm{k} \Omega$.

Prachita Kush
Prachita Kush
Numerade Educator
02:31

Problem 9

The input impedance to a common-emitter transistor amplifier is $1.2 \mathrm{k} \Omega$ with $\beta=140$, $r_{o}=50 \mathrm{k} \Omega$, and $R_{L}=2.7 \mathrm{k} \Omega$. Determine:
a. $r_{e}$
b. $I_{b}$ if $V_{i}=30 \mathrm{mV}$.
c. $I_{c}$.
d. $A_{i}=I_{o} / I_{i}=I_{L} / I_{b}$.
e. $A_{v}=V_{o} / V_{i}$

Aman Kumar
Aman Kumar
Numerade Educator
01:06

Problem 10

For the common-base configuration of Fig. 18 , the dc emitter current is $3.2 \mathrm{~mA}$ and $\alpha$ is $0.99 .$ Determine the following if the applied voltage is $48 \mathrm{mV}$ and the load is $2.2 \mathrm{k} \Omega$.
a. $r_{c}$
b. $Z_{i}$
c. $I_{c}$.
d. $V_{o}$.
e. $A_{v}$
f. $I_{b}$ -

Narayan Hari
Narayan Hari
Numerade Educator
05:14

Problem 11

For the network of Fig. 151 :
a. Determine $Z_{i}$ and $Z_{o}$.
b. Find $A_{r}$
c. Repeat parts (a) and $(b)$ with $r_{0}=20 \mathrm{k} \Omega$.

Kajal Gautam
Kajal Gautam
Numerade Educator
01:07

Problem 12

For the network of Fig. 152, determine $V_{C C}$ for a voltage gain of $A_{v}=-160$.

Dominador Tan
Dominador Tan
Numerade Educator
06:59

Problem 13

For the network of Fig. 153 :
a. Calculate $I_{B}, I_{C}$, and $r_{e}$.
b. Determine $Z_{i}$ and $Z_{o}$.
c. Calculate $A_{v^{*}}$
d. Determine the effect of $r_{o}=30 \mathrm{k} \Omega$ on $A_{\gamma}$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:58

Problem 14

For the network of Fig. 153, what value of $R_{C}$ will cut the voltage gain to half the value obtained in problem $13 ?$

Narayan Hari
Narayan Hari
Numerade Educator
05:37

Problem 15

For the network of Fig. 154 :
a. Determine $r_{e}$.
b. Calculate $Z_{i}$ and $Z_{o}$.
c. Find $A_{y}$
d. Repeat parts (b) and (c) with $r_{o}=25 \mathrm{k} \Omega$.

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
01:42

Problem 16

Determine $V_{C C}$ for the network of Fig. 155 if $A_{v}=-160$ and $r_{o}=100 \mathrm{k} \Omega$.

Kratika Bhadauria
Kratika Bhadauria
Numerade Educator
06:59

Problem 17

For the network of Fig. 156 :
a. Determine $r_{e}$.
b. Calculate $V_{B}$ and $V_{C}$.
c. Determine $Z_{i}$ and $A_{v}=V_{o} / V_{i}$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:59

Problem 18

For the network of Fig. 157 :
a. Determine $r_{e}$
b. Find the dc voltages $V_{B}, V_{C B}$, and $V_{C E}$.
c. Determine $Z_{i}$ and $Z_{o}$.
d. Calculate $A_{v}=V_{o} / V_{i}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:59

Problem 19

For the network of Fig. 158 :
a. Determine $r_{e}$ e
b. Find $Z_{i}$ and $Z_{o}$.
c. Calculate $A_{v}$.
d. Repeat parts (b) and (c) with $r_{o}=20 \mathrm{k} \Omega$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:49

Problem 20

Repeat Problem 19 with $R_{E}$ bypassed. Compare results.

James Kiss
James Kiss
Numerade Educator
01:42

Problem 21

For the network of Fig. 159, determine $R_{E}$ and $R_{B}$ if $A_{v}=-10$ and $r_{e}=3.8 \Omega$. Assume that $Z_{b}=\beta R_{E}$

Kratika Bhadauria
Kratika Bhadauria
Numerade Educator
06:59

Problem 22

For the network of Fig. 160 :
a, Determine $r_{e}$.
b. Find $Z_{i}$ and $A_{v}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:59

Problem 23

For the network of Fig. 161 :
a. Determine $r_{e}$
b. Calculate $V_{B}, V_{C E}$, and $V_{C B}$.
c. Determine $Z_{i}$ and $Z_{o}$.
d. Calculate $A_{v}=V_{o} / V_{i} .$
e. Determine $A_{i}=I_{o} / I_{i}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
05:14

Problem 24

For the network of Fig. 162 :
a. Determine $r_{e}$ and $\beta r_{e}$.
b. Find $Z_{i}$ and $Z_{o}$.
c. Calculate $A_{y}$.

Kajal Gautam
Kajal Gautam
Numerade Educator
06:59

Problem 25

For the network of Fig. 163 :
a. Determine $Z_{i}$ and $Z_{o}$.
b. Find $A_{y}$
c. Calculate $V_{o}$ if $V_{i}=1 \mathrm{mV}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:59

Problem 26

For the network of Fig. 164 :
a. Calculate $I_{B}$ and $I_{C}$.
b. Determine $r_{e} .$
c. Determine $Z_{i}$ and $Z_{o}$.
d. Find $\bar{A}_{v}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:18

Problem 27

For the common-base configuration of Fig. 165 :
a. Determine $r_{e}$ e
b. Find $Z_{i}$ and $Z_{o}$.
c. Calculate $A_{\mathrm{y}}$

Dr. Satish Ingale
Dr. Satish Ingale
Numerade Educator
06:59

Problem 28

For the network of Fig. 166 , determine $A_{v}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:59

Problem 29

For the collector feedback configuration of Fig. 167 :
a. Determine $r_{e}$.
b. Find $Z_{i}$ and $Z_{o}$.
c. Calculate $\overline{A_{v}}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:42

Problem 30

Given $r_{e}=10 \Omega, \beta=200, A_{v}=-160$, and $A_{i}=19$ for the network of Fig. 168 , determine $R_{C}, R_{F}$, and $V_{C C}$

Kratika Bhadauria
Kratika Bhadauria
Numerade Educator
06:52

Problem 31

For the network of Fig. 49 :
a. Derive the approximate equation for $A_{v}$
b. Derive the approximate equations for $Z_{i}$ and $Z_{o}$.
c. Given $R_{C}=2.2 \mathrm{k} \Omega, R_{F}=120 \mathrm{k} \Omega, R_{E}=1.2 \mathrm{k} \Omega, \beta=90$, and $V_{C C}=10 \mathrm{~V}$, calculate
the magnitudes of $A_{v}, Z_{i}$, and $Z_{o}$ using the equations of parts (a) and (b).

Amit Srivastava
Amit Srivastava
Numerade Educator
06:59

Problem 32

For the network of Fig. 169 :
a. Determine $Z_{i}$ and $Z_{o}$.
b. Find $A_{v}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:37

Problem 33

Repeat problem 32 with the addition of an emitter resistor $R_{E}=0.68 \mathrm{k} \Omega$.

Vishal Gupta
Vishal Gupta
Numerade Educator
05:43

Problem 34

For the fixed-bias configuration of Fig. 170 :
a. Determine $A_{v_{\mathrm{N}}}, Z_{i}$, and $Z_{o}$.
b. Sketch the two-port model of Fig. 63 with the parameters determined in part (a) in place.
c. Calculate the gain $A_{v_{L}}=V_{o} / V_{i}$.
d. Determine the current gain $A_{i_{L}}=I_{o} / I_{i}$.

Nikhil Kumar Rajpurohit
Nikhil Kumar Rajpurohit
Numerade Educator
08:56

Problem 35

a. Determine the voltage gain $A_{v_{L}}$ for the network of Fig. 170 for $R_{L}=4.7 \mathrm{k} \Omega, 2.2 \mathrm{k} \Omega$, and $0.5 \mathrm{k} \Omega$. What is the effect of decreasing levels of $R_{L}$ on the voltage gain?
b. How will $Z_{i}, Z_{o}$, and $A_{v_{\mathrm{NL}}}$ change with decreasing values of $R_{L}$ ?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:59

Problem 36

For the network of Fig. 171 :
a. Determine $A_{v_{\mathrm{N}}}, Z_{i}$, and $Z_{o}$.
b. Sketch the two-port model of Fig. 63 with the parameters determined in part (a) in place.
c. Determine $A_{v}=V_{o} / V_{i}$
d. Determine $A_{v_{s}}=V_{o} / V_{s}$.
e. Change $R_{s}$ to $1 \mathrm{k} \Omega$ and determine $A_{v} .$ How does $A_{v}$ change with the level of $R_{s}$ ?
f. Change $R_{s}$ to $1 \mathrm{k} \Omega$ and determine $A_{v_{j}} .$ How does $A_{v_{c}}$ change with the level of $R_{s}$ ?
g. Change $R_{s}$ to $1 \mathrm{k} \Omega$ and determine $A_{v_{\mathrm{NL}}}, Z_{i}$, and $Z_{o}$. How do they change with the change in $R_{s}$ ?
h. For the original network of Fig. 171 calculate $A_{i}=I_{o} / I_{i}$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:45

Problem 37

For the network of Fig. 172:
a. Determine $A_{v_{\mathrm{LL}}}, Z_{i}$, and $Z_{o}$.
b. Sketch the two-port model of Fig. 63 with the parameters determined in part (a) in place.
c. Determine $A_{v_{L}}$ and $A_{v_{s}}$.
d. Calculate $A_{i_{2}}$
e. Change $R_{L}$ to $5.6 \mathrm{k} \Omega$ and calculate $A_{v_{j}} .$ What is the effect of increasing levels of $R_{L}$ on the gain?
f. Change $R_{s}$ to $0.5 \mathrm{k} \Omega$ (with $R_{L}$ at $2.7 \mathrm{k} \Omega$ ) and comment on the effect of reducing $R_{s}$ on $A_{v_{v}}$
g. Change $R_{L}$ to $5.6 \mathrm{k} \Omega$ and $R_{s}$ to $0.5 \mathrm{k} \Omega$ and determine the new levels of $Z_{i}$ and $Z_{o}$. How are the impedance parameters affected by changing levels of $R_{L}$ and $R_{s} ?$

Narayan Hari
Narayan Hari
Numerade Educator
01:38

Problem 38

For the voltage-divider configuration of Fig. 173 :
a. Determine $A_{v_{\mathrm{NL}}}, Z_{i}$, and $Z_{o}$.
b. Sketch the two-port model of Fig. 63 with the parameters determined in part (a) in place.
c. Calculate the gain $A_{v_{v}}$
d. Determine the current gain $A_{i,}$.
e. Determine $A_{y}, A_{i,}$, and $Z_{o}$ using the $r_{e}$ model and compare solutions.

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
08:56

Problem 39

a. Determine the voltage gain $A_{v_{L}}$ for the network of Fig. 173 with $R_{L}=4.7 \mathrm{k} \Omega, 2.2 \mathrm{k} \Omega$, and $0.5 \mathrm{k} \Omega$. What is the effect of decreasing levels of $R_{L}$ on the voltage gain?
b. How will $Z_{i}, Z_{o}$, and $A_{v_{\mathrm{NL}}}$ change with decreasing levels of $R_{L}$ ?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:17

Problem 40

For the emitter-stabilized network of Fig. 174 :
a. Determine $A_{v_{\mathrm{N}},} Z_{i}$, and $Z_{o}$.
b. Sketch the two-port model of Fig. 63 with the values determined in part (a).
c. Determine $A_{v_{L}}$ and $A_{v_{v}}$.
d. Change $R_{s}$ to $1 \mathrm{k} \Omega$. What is the effect on $A_{v_{\mathrm{NL}}}, Z_{i}$, and $Z_{o}$ ?
e. Change $R_{s}$ to $1 \mathrm{k} \Omega$ and determine $A_{v_{L}}$ and $A_{v_{s}}$. What is the effect of increasing levels of $R_{s}$ on $A_{v_{L}}$ and $A_{v_{s}}$ ?
f. Determine $A_{i}=I_{o} / I_{i}$

Chai Santi
Chai Santi
Numerade Educator
01:24

Problem 41

For the network of Fig. 175 :
a. Determine $A_{v_{\mathrm{N}}}, Z_{i}$, and $Z_{o}$.
b. Sketch the two-port model of Fig. 63 with the values determined in part (a).
c. Determine $A_{v_{L}}$ and $A_{v_{s}}$
d. Change $R_{s}$ to $1 \mathrm{k} \Omega$ and determine $A_{v_{L}}$ and $A_{v_{s}^{*}}$. What is the effect of increasing levels of $R_{s}$ on the voltage gains?
e. Change $R_{s}$ to $1 \mathrm{k} \Omega$ and determine $A_{v_{\mathrm{N}},}, Z_{i}$, and $Z_{o}$. What is the effect of increasing levels of $R_{s}$ on the parameters?
f. Change $R_{L}$ to $5.6 \mathrm{k} \Omega$ and determine $A_{v_{L}}$ and $A_{v_{s}}$. What is the effect of increasing levels of $R_{L}$ on the voltage gains? Maintain $R_{s}$ at its original level of $0.6 \mathrm{k} \Omega$.
g. Determine $A_{i}=\frac{I_{o}}{I_{i}}$ with $R_{L}=2.7 \mathrm{k} \Omega$ and $R_{s}=0.6 \mathrm{k} \Omega$.

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
08:49

Problem 42

For the common-base network of Fig. 176:
a. Determine $Z_{i}, Z_{o}$, and $\bar{A}_{v_{\mathrm{ML}}}$.
b. Sketch the two-port model of Fig. 63 with the parameters of part (a) in place.
c. Determine $A_{v_{l}}$ and $A_{v_{v}}$.
d. Determine $A_{v_{L}}$ and $A_{v_{t}}$ using the $r_{e}$ model and compare with the results of part (c).
e. Change $R_{s}$ to $0.5 \mathrm{k} \Omega$ and $R_{L}$ to $2.2 \mathrm{k} \Omega$ and calculate $A_{v_{L}}$ and $A_{v_{s}} .$ What is the effect of changing levels of $R_{s}$ and $R_{L}$ on the voltage gains?
f. Determine $Z_{o}$ if $R_{s}$ changed to $0.5 \mathrm{k} \Omega$ with all other parameters as appearing in Fig. 176 . How is $Z_{o}$ affected by changing levels of $R_{s} ?$
g. Determine $Z_{i}$ if $R_{L}$ is reduced to $2.2 \mathrm{k} \Omega$. What is the effect of changing levels of $R_{L}$ on the input impedance?
h. For the original network of Fig. 176 determine $A_{i}=I_{o} / I_{i}$

M Hassan Anwar
M Hassan Anwar
Numerade Educator
01:51

Problem 43

For the cascaded system of Fig. 177 with two identical stages, determine:
a. The loaded voltage gain of each stage.
b. The total gain of the system, $A_{v}$ and $A_{v_{s}}$.
c. The loaded current gain of each stage.
d. The total current gain of the system $A_{i_{L}}=I_{o} / I_{i}$.
e. How $Z_{i}$ is affected by the second stage and $R_{L}$.
f. How $Z_{o}$ is affected by the first stage and $R_{s}$.
g. The phase relationship between $V_{o}$ and $V_{i}$.

Dominador Tan
Dominador Tan
Numerade Educator
01:51

Problem 44

For the cascaded system of Fig. 178 , determine:
a. The loaded voltage gain of each stage.
b. The total gain of the system, $A_{v_{L}}$ and $A_{v_{s}}$
c. The loaded current gain of each stage.
d. The total current gain of the system.
e. How $Z_{i}$ is affected by the second stage and $R_{L}$.
f. How $Z_{o}$ is affected by the first stage and $R_{s}$.
g. The phase relationship between $V_{o}$ and $V_{i}$.

Dominador Tan
Dominador Tan
Numerade Educator
01:51

Problem 45

For the BJT cascade amplifier of Fig. 179, calculate the dc bias voltages and collector current for each stage.

Dominador Tan
Dominador Tan
Numerade Educator
01:51

Problem 46

a. Calculate the voltage gain of each stage and the overall ac voltage gain for the BJT cascade amplifier circuit of Fig. $179 .$
b. Find $A_{i_{T}}=I_{o} / I_{i}$.

Dominador Tan
Dominador Tan
Numerade Educator
04:41

Problem 47

For the cascode amplifier circuit of Fig. 180 , calculate the dc bias voltages $V_{B_{1}}, V_{B_{2}}$, and $V_{C_{2}}$.

Thomas Thompson
Thomas Thompson
Numerade Educator
01:51

Problem 48

For the cascode amplifier circuit of Fig. 180, calculate the voltage gain $A_{v}$ and output voltage $V_{o}$

Dominador Tan
Dominador Tan
Numerade Educator
00:57

Problem 49

Calculate the ac voltage across a $10-\mathrm{k} \Omega$ load connected at the output of the circuit in Fig. $180 .$

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
02:11

Problem 50

For the Darlington network of Fig. 181 :
a. Determine the dc levels of $V_{B_{1}}, V_{C_{1}}, V_{E_{2}}, V_{C B_{1}}$, and $V_{C E_{2}^{2}}$
b. Find the currents $I_{B_{1}}, I_{B_{2}}$, and $I_{E_{2}^{-}}$
c. Calculate $Z_{i}$ and $Z_{o}$.
d. Determine the voltage gain $A_{v}=V_{o} / V_{i}$ and current gain $A_{i}=I_{o} / I_{i} .$

Kajal Gautam
Kajal Gautam
Numerade Educator
01:00

Problem 51

Repeat problem 50 with a load resistor of $1.2 \mathrm{k} \Omega$.

Mayukh Banik
Mayukh Banik
Numerade Educator
03:13

Problem 52

Determine $A_{v}=V_{o} / V_{s}$ for the network of Fig. 181 if the source has an internal resistance of $1.2$ $\mathrm{k} \Omega$ and the applied load is $10 \mathrm{k} \Omega$.

Ajay Singhal
Ajay Singhal
Numerade Educator
03:18

Problem 53

A resistor $R_{C}=470 \Omega$ is added to the network of Fig. 181 along with a bypass capacitor $C_{E}=5 \mu \mathrm{F}$ across the emitter resistor. If $\beta_{D}=4000, V_{B E_{T}}=1.6 \mathrm{~V}$, and $r_{o_{1}}=r_{o_{2}}=40 \mathrm{k} \Omega$
for a packaged Darlington amplifier:
a. Find the dc levels of $V_{B_{1}}, V_{E_{2}}$, and $V_{C E_{2}}$.
b. Determine $Z_{i}$ and $Z_{o}$.
c. Determine the voltage gain $A_{v}=V_{o} / V_{i}$ if the output voltage $V_{o}$ is taken off the collector terminal via a coupling capacitor of $10 \mu \mathrm{F}$.

Prachita Kush
Prachita Kush
Numerade Educator
02:11

Problem 54

For the feedback pair of Fig. 182 :
a. Calculate the de voltages $V_{B}, V_{B,}, V_{C_{1}}, V_{C_{2}}, V_{E_{1}}$, and $V_{E_{2}}$.
b. Determine the dc currents $I_{B_{1}}, I_{C_{1}}, I_{B_{2}}, I_{C_{2}}$, and $I_{E_{2}}$.
c. Calculate the impedances $Z_{i}$ and $Z_{o}$.
d. Find the voltage gain $A_{v}=V_{o} / V_{i}$.
e. Determine the current gain $A_{i}=I_{o} / I_{i}$

Kajal Gautam
Kajal Gautam
Numerade Educator
02:07

Problem 55

Repeat problem 54 if a $22-\Omega$ resistor is added between $V_{E}$, and ground.

Mayukh Banik
Mayukh Banik
Numerade Educator
02:07

Problem 56

Repeat problem 54 if a load resistance of $1.2 \mathrm{k} \Omega$ is introduced.

Mayukh Banik
Mayukh Banik
Numerade Educator
02:43

Problem 57

Given $I_{E}(\mathrm{dc})=1.2 \mathrm{~mA}, \beta=120$, and $r_{o}=40 \mathrm{k} \Omega$, sketch the following:
a. Common-emitter hybrid equivalent model.
b. Common-emitter $r_{e}$ equivalent model.
c. Common-base hybrid equivalent model.
d. Common-base $r_{e}$ equivalent model.

Aman Kumar
Aman Kumar
Numerade Educator
02:43

Problem 58

Given $h_{i e}=2.4 \mathrm{k} \Omega, h_{f e}=100, h_{r e}=4 \times 10^{-4}$, and $h_{o e}=25 \mu \mathrm{S}$, sketch the following:
a. Common-emitter hybrid equivalent model.
b. Common-emitter $r_{e}$ equivalent model.
c. Common-base hybrid equivalent model.
d. Common-base $r_{e}$ equivalent model.

Aman Kumar
Aman Kumar
Numerade Educator
02:21

Problem 59

Redraw the common-emitter network of Fig. 3 for the ac response with the approximate hybrid equivalent model substituted between the appropriate terminals.

Amit Srivastava
Amit Srivastava
Numerade Educator
03:29

Problem 60

Redraw the network of Fig. 183 for the ac response with the $r_{e}$ model inserted between the appropriate terminals. Include $r_{o}$.

Narayan Hari
Narayan Hari
Numerade Educator
03:29

Problem 61

Redraw the network of Fig. 184 for the ac response with the $r_{e}$ model inserted between the appropriate terminals. Include $r_{o}$

Narayan Hari
Narayan Hari
Numerade Educator
01:55

Problem 62

Given the typical values of $h_{i e}=1 \mathrm{k} \Omega, h_{r e}=2 \times 10^{-4}$, and $A_{v}=-160$ for the input configuration of Fig. 185 :
a. Determine $V_{o}$ in terms of $V_{i}$.
b. Calculate $I_{b}$ in terms of $V_{i}$.
c. Calculate $I_{b}$ if $h_{r e} V_{o}$ is ignored.
d. Determine the percentage difference in $I_{b}$ using the following equation:
$$
\text { difference in } I_{b}=\frac{I_{b}\left(\text { without } h_{\text {re }}\right)-I_{b}\left(\text { with } h_{\text {re }}\right)}{I_{b}\left(\text { without } h_{r e}\right)} \times 100 \%
$$
e. Is it a valid approach to ignore the effects of $h_{r e} V_{o}$ for the typical values employed in this example?

Chai Santi
Chai Santi
Numerade Educator
02:03

Problem 63

Given the typical values of $R_{L}=2.2 \mathrm{k} \Omega$ and $h_{o e}=20 \mu \mathrm{S}$, is it a good approximation to ignore the effects of $1 / h_{o e}$ on the total load impedance? What is the percentage difference in total loading on the transistor using the following equation?
$$
\% \text { difference in total load }=\frac{R_{L}-R_{L} \|\left(1 / h_{o e}\right)}{R_{L}} \times 100 \%
$$

Prachita Kush
Prachita Kush
Numerade Educator
02:08

Problem 64

Repeat Problem 62 using the average values of the parameters of Fig. 92 with $A_{v}=-180$.

Uma Kumari
Uma Kumari
Numerade Educator
03:34

Problem 65

Repeat Problem 63 for $R_{L}=3.3 \mathrm{k} \Omega$ and the average value of $h_{o e}$ in Fig. $92 .$

M Hassan Anwar
M Hassan Anwar
Numerade Educator
01:13

Problem 66

a. Given $\beta=120, r_{e}=4.5 \Omega$, and $r_{o}=40 \mathrm{k} \Omega$, sketch the approximate hybrid equivalent circuit.
b. Given $h_{i e}=1 \mathrm{k} \Omega, h_{r e}=2 \times 10^{-4}, h_{f e}=90$, and $h_{o e}=20 \mu \mathrm{S}$, sketch the $r_{e}$ model.

Manik Pulyani
Manik Pulyani
Numerade Educator
46:02

Problem 67

For the network of Problem 11 :
a. Determine $r_{e}$.
b. Find $h_{f e}$ and $h_{i e}$.
c. Find $Z_{i}$ and $Z_{o}$ using the hybrid parameters.
d. Calculate $A_{v}$ and $A_{i}$ using the hybrid parameters.
e. Determine $Z_{i}$ and $Z_{o}$ if $h_{o e}=50 \mu \mathrm{S}$.
f. Determine $A_{v}$ and $A_{i}$ if $h_{o e}=50 \mu \mathrm{S}$.
g. Compare the solutions above with those of Problem 9. (Note: The solutions are available in the appendix "Solutions to Selected Odd-Numbered Problems" if Problem 11 was not performed.)

Oswaldo Jiménez
Oswaldo Jiménez
Numerade Educator
06:59

Problem 68

For the network of Fig. 186 :
a. Determine $Z_{i}$ and $Z_{o}$.
b. Calculate $A_{v}$ and $A_{i}$
c. Determine $r_{e}$ and compare $\beta r_{e}$ to $h_{i e}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
05:14

Problem 69

For the common-base network of Fig. 187:
a. Determine $Z_{i}$ and $Z_{o}$.
b. Calculate $A_{v}$ and $A_{i}$
c. Determine $\alpha, \beta, r_{e}$, and $r_{o}$ o

Kajal Gautam
Kajal Gautam
Numerade Educator
01:44

Problem 70

Repeat parts (a) and (b) of Problem 68 with $h_{r e}=2 \times 10^{-4}$ and compare results.

Manik Pulyani
Manik Pulyani
Numerade Educator
06:59

Problem 71

For the network of Fig. 188 , determine:
a. $Z_{i}$
b. $A_{v}$
c. $A_{i}=I_{o} / I_{i}$.
d. $Z_{o}$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:29

Problem 72

For the common-base amplifier of Fig. 189, determine:
a. $Z_{i}$
b. $A_{i}$
c. $A_{y}$
d. $Z_{o}$.

Prachita Kush
Prachita Kush
Numerade Educator
03:18

Problem 73

a. Sketch the Giacoletto (hybrid $\pi$ ) model for a common-emitter transistor if $r_{b}=4 \Omega$, $C_{m}=5 \mathrm{pF}, C_{u}=1.5 \mathrm{pF}, h_{o e}=18 \mu \mathrm{S}, \beta=120$, and $r_{e}=14 .$
b. If the applied load is $1.2 \mathrm{k} \Omega$ and the source resistance is $250 \Omega$, draw the approximate hybrid $\pi$ model for the low- and mid-frequency range.

Prachita Kush
Prachita Kush
Numerade Educator
02:35

Problem 74

a. Using Fig. 124 , determine the magnitude of the percentage change in $h_{f e}$ for an $I_{C}$ change from $0.2 \mathrm{~m} \mathrm{~A}$ to $1 \mathrm{~m}$ A using the equation
$$
\% \text { change }=\left|\frac{h_{f e}(0.2 \mathrm{~mA})-h_{f e}(1 \mathrm{~mA})}{h_{f e}(0.2 \mathrm{~mA})}\right| \times 100 \%
$$
b. Repeat part (a) for an $I_{C}$ change from $1 \mathrm{~mA}$ to $5 \mathrm{~mA}$.

Priyanka Sadarangani
Priyanka Sadarangani
Numerade Educator
02:09

Problem 75

Repeat Problem 74 for $h_{i e}$ (same changes in $I_{C}$ ).

Arpit Gupta
Arpit Gupta
Numerade Educator
02:40

Problem 76

a. If $h_{o e}=20 \mu \mathrm{S}$ at $I_{C}=1 \mathrm{~mA}$ on Fig. 124, what is the approximate value of $h_{o e}$ at $I_{C}=0.2 \mathrm{~mA} ?$
b. Determine its resistive value at $0.2 \mathrm{~mA}$ and compare to a resistive load of $6.8 \mathrm{k} \Omega$. Is it a good approximation to ignore the effects of $1 / h_{\text {oe }}$ in this case?

Zhuxi Luo
Zhuxi Luo
Numerade Educator
02:41

Problem 77

a. If $h_{o e}=20 \mu \mathrm{S}$ at $I_{C}=1 \mathrm{~mA}$ of Fig. 124, what is the approximate value of $h_{o e}$ at $I_{C}=10 \mathrm{~mA} ?$
b. Determine its resistive value at $10 \mathrm{~mA}$ and compare to a resistive load of $6.8 \mathrm{k} \Omega$. Is it a good approximation to ignore the effects of $1 / h_{o e}$ in this case?

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
02:19

Problem 78

a. If $h_{r e}=2 \times 10^{-4}$ at $I_{C}=1 \mathrm{~mA}$ on Fig. 124, determine the approximate value of $h_{r e}$ at $0.1$ $\mathrm{mA} .$
b. For the value of $h_{r e}$ determined in part (a), can $h_{r e}$ be ignored as a good approximation if $A_{v}=210 ?$

Sheryl Ezze
Sheryl Ezze
Numerade Educator
01:49

Problem 79

a. Based on a review of the characteristics of Fig. 124, which parameter changed the least for the full range of collector current?
b. Which parameter changed the most?
c. What are the maximum and minimum values of $1 / h_{o e} ?$ Is the approximation $1 / h_{o e} \| R_{L} \cong R_{L}$ more appropriate at high or low levels of collector current?
d. In which region of current spectrum is the approximation $h_{r e} V_{c e} \cong 0$ the most appropriate?

Aja S
Aja S
Numerade Educator
01:48

Problem 80

a. Based on a review of the characteristics of Fig. 126, which parameter changed the most with increase in temperature?
b. Which changed the least?
c. What are the maximum and minimum values of $h_{f e} ?$ Is the change in magnitude significant? Was it expected?
d. How does $r_{e}$ vary with increase in temperature? Simply calculate its level at three or four points and compare their magnitudes.
e. In which temperature range do the parameters change the least?

Ricajoy Montero
Ricajoy Montero
Numerade Educator
03:01

Problem 81

Given the network of Fig. 190 :
a. Is the network properly biased?
b. What problem in the network construction could cause $V_{B}$ to be $6.22 \mathrm{~V}$ and obtain the given waveform of Fig. $190 ?$

Thomas Thompson
Thomas Thompson
Numerade Educator
02:11

Problem 82

Using PSpice Windows, determine the voltage gain for the network of Fig. 25. Display the input and output waveforms.

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
02:28

Problem 83

Using PSpice Windows, determine the voltage gain for the network of Fig. 32. Display the input and output waveforms.

Kajal Gautam
Kajal Gautam
Numerade Educator
00:35

Problem 84

Using PSpice Windows, determine the voltage gain for the network of Fig. 44. Display the input and output waveforms.

Sana Maqsad
Sana Maqsad
Numerade Educator
01:56

Problem 85

Using Multisim, determine the voltage gain for the network of Fig. 28 .

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
01:56

Problem 86

Using Multisim, determine the voltage gain for the network of Fig. 39 .

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
06:59

Problem 87

Using PSpice Windows, determine the level of $V_{o}$ for $V_{i}=1 \mathrm{mV}$ for the network of Fig. $69 .$ For the capacitive elements assume a frequency of $1 \mathrm{kH} z$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:05

Problem 88

Repeat Problem 87 for the network of Fig. 71 .

Carson Merrill
Carson Merrill
Numerade Educator
06:25

Problem 89

Repeat Problem 87 for the network of Fig. $82 .$

Tanishq Gupta
Tanishq Gupta
Numerade Educator
02:13

Problem 90

Repeat Problem 87 using Multisim.

Kajal Gautam
Kajal Gautam
Numerade Educator
02:13

Problem 91

Repeat Problem 87 using Multisim.

Kajal Gautam
Kajal Gautam
Numerade Educator