Download Chapter 05-Electrical Circuit Analysis-Problem Solutions and more Exercises Electrical Circuit Analysis in PDF only on Docsity! Chapter 5, Problem 1. The equivalent model of a certain op amp is shown in Fig. 5.43. Determine: (a) the input resistance. (b) the output resistance. (c) the voltage gain in dB. Figure 5.43 for Prob. 5.1 8x104vd Chapter 5, Solution 1. (a) Rin = 1.5 MΩ (b) Rout = 60 Ω (c) A = 8x104 Therefore AdB = 20 log 8x104 = 98.0 dB Chapter 5, Problem 2 The open-loop gain of an op amp is 100,000. Calculate the output voltage when there are inputs of +10 µV on the inverting terminal and + 20 µV on the noninverting terminal. Chapter 5, Solution 2. v0 = Avd = A(v2 - v1) = 105 (20-10) x 10-6 = 1V docsity.com Chapter 5, Problem 3 Determine the output voltage when .20 µV is applied to the inverting terminal of an op amp and +30 µV to its noninverting terminal. Assume that the op amp has an open-loop gain of 200,000. Chapter 5, Solution 3. v0 = Avd = A(v2 - v1) = 2 x 105 (30 + 20) x 10-6 = 10V Chapter 5, Problem 4 The output voltage of an op amp is .4 V when the noninverting input is 1 mV. If the open-loop gain of the op amp is 2 × 106, what is the inverting input? Chapter 5, Solution 4. v0 = Avd = A(v2 - v1) v2 - v1 = V2 10x2 4 A v 6 0 μ−= − = v2 - v1 = -2 µV = –0.002 mV 1 mV - v1 = -0.002 mV v1 = 1.002 mV docsity.com Chapter 5, Problem 6 Using the same parameters for the 741 op amp in Example 5.1, find vo in the op amp circuit of Fig. 5.45. Figure 5.45 for Prob. 5.6 Example 5.1 A 741 op amp has an open-loop voltage gain of 2×105, input resistance of 2 MΩ, and output resistance of 50Ω. The op amp is used in the circuit of Fig. 5.6(a). Find the closed- loop gain vo/vs . Determine current i when vs = 2 V. docsity.com Chapter 5, Solution 6. + - Avd -+ vi I Rin R0 + vo - - vd + (R0 + Ri)R + vi + Avd = 0 But vd = RiI, vi + (R0 + Ri + RiA)I = 0 I = i0 i R)A1(R v ++ − (1) -Avd - R0I + vo = 0 vo = Avd + R0I = (R0 + RiA)I Substituting for I in (1), v0 = ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ ++ + − i0 i0 R)A1(R ARR vi = ( )( ) 65 356 10x2x10x2150 1010x2x10x250 ++ ⋅+ − − ≅ mV 10x2x001,200 10x2x000,200 6 6− v0 = -0.999995 mV docsity.com Chapter 5, Problem 7 The op amp in Fig. 5.46 has Ri = 100 kΩ, Ro = 100 Ω, A = 100,000. Find the differential voltage vd and the output voltage vo. + – Figure 5.46 for Prob. 5.7 docsity.com
