ENGR 2219 - Linear Circuits I

Homework Answers

 

Note:  This is for the 9th Edition of the textbook 

 

Homework 1

2.1)  P_dev = 300 W

2.7)  The interconnection is invalid

2.8) P_dev = P_abs = 210 W

2.18)  i₁ = 1.2 A, i₂ = 0.3 A, v₀ = 120 V, P_dev = P_abs = 180 W

2.22)  i₁ = 2.0 A, P_4Ω = 100 W, P_50Ω = 50 W, P_65Ω = 260 W, P_10Ω = 90 W, P_25Ω = 400 W, P_dev = P_dev = 900 W

 

 

Homework 2

3.5) (a) 20 Ω, (b) 15 kΩ

3.10) 80 W

3.29) (a) 20 A, (b) 1080 W

 

Homework 3

4.6) v₁ = 100 V, v₂ = 20 V 

4.17) P_dev = P_abs = 8800 W

4.22) i₁ = -10 mA, i₂ = 40 mA, i₃ = -70 mA, P_dev = P_abs = 6.5 W

4.34) P_dev = P_abs = 17,940 W  

4.45) P_dev = P_abs = 2400 W

4.59) (a) 20 mA

4.63) v_Th = 60 V, R_Th = 10 Ω

 

Homework 4

(a) I = 6 mA, V = 0

(b) I = 0, V = 0

(c) I = 3.33 mA, V = 3.33 V

(d) I = 0, V = 6.67 V

(e) I = 16.67 mA, V = 20 V

 

Homework 5

Handout 1

(1) I_C = 1.93 mA, V_CE = 10.35 V

(2) I_C = 9.9 mA, V_CE = -0.2 V

(3) I_C = 0 mA, V_CE = 10 V

(4) (a) I_C = 3.1 mA, V_CE = 0.2 V (b) I_C = 3.61 mA, V_CE = 1.84 V

 

Handout 2

(1) I_D = 2.82 mA, V_DS = 11.54 V

(2) I_D = 0.54 mA, V_DS = 9.9 V

 

Homework 6

5.2) -1 mA

 

5.3)

(a) -15 V 

(b) -10 V

(c) -4 V

(d) 7 V

(e) 15 V

(f) -1.08 to 4.92 V 

 

5.12)   

(a) Summing Amplifier 

(b) -6 V

(c) -0.5 to 2 V

 

5.17)

(a) Non-inverting Amplifier 

(b) v₀ = 2v_s V

(c) -6 to 4 V

 

5.26) 20 kΩ

 

Homework 7

6.1)

0 < t < 2:  i_L(t) = -0.3e^-4t + 1.3 A

t > 2:  i_L(t) = -0.3e^-4(t-2) A

 

6.2)

(a) 900e-^10t(1-10t) µV

(b) -59.34 µW

(c) delivering

(d) 487.21 mA

(e) 10.96 µJ

 

6.16)

(a) -50 x 10⁴t +15 V

(b)  10⁶t V

(c) 1.6 x 10⁶t - 12 V

(d) 52 V

 

6.17)

0 < t < 0.5:  1.2t mA

(b) 0.5< t < 1:  1.2(t - 1) mA

 

Homework 8

7.4)

(a) 5 mA and 15 mA

(b) 5 mA and -5 mA

(c) 5e^-20,000t mA

(d) -5e^-20,000t mA

 

7.23)

(a) i(t) = 1.6e^-50t mA, v₁(t) = 32e^-50t + 8 V, v₂(t) = -8e^-50t + 8 V

(b) 800 μJ

(c) energy trapped = 160 μJ, energy dissipated = 640 μJ

 

7.36)

(a) -5 mA

(b) 0.33 mA

(c) 5 x 10^-6 s

(d) 0.33 - 5.33e^-200,000t mA

 

7.55)

(a) 50 V

(b) -24 V

(c) 0.1 x 10^-6 s

(d) -18.5 A

(e) -24 + 74e^-10,000,000t V

(f) -18.5e^-10,000,000t A

 

Homework 9

8.1)

(a) -10,000 and -40,000 rad/s

(b) overdamped

(c) 3125 Ω

(d) -16,000 + j12,000 and -16,000 - j12,000 rad/s

(e) 2500 Ω

 

8.3)

(a) i_R(0⁺) = 48 mA, i_L(0⁺) = -45 mA, i_C(0⁺) = -3 mA

(b) 15e^-8000tcos6000t + 17.5e^-8000tsin6000t V

 

8.39)

(a) 10,000 Ω and 0.5H

(b) i(0) = 0, di(0)/dt = 48 A/s

(c) 4e^-4000t - 4e^-16,000t mA

(d) 115.52 μA

(e) 1.89 mA

(f) -8e^-1000t + 32e^-4000t V

 

8.44)

(a) 1250 Ω

(b) i(0⁺) = 6 mA, di(0⁺)/dt = 60 A/s

(c) v_C(t) = 56,250te^-5000t + 15e^-5000t V

 

Homework 10

9.15)

(c) 8.32 cos(8000t + 76.31°) A

 

9.29)

42.43cos(50,000t + 45°) V

 

9.32)

42.43cos(2000t + 45°) V

 

9.44)

(a) 350 V

(b) 100 + j100 Ω

 

 

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