For an ideal op-amp, the voltage gain and input resistance

An amplifier has a gain of 15 and the input waveform shown in Fig. P4.1. Draw the output waveform. in (mV) t (s) 50 100 150 50 150 100 0 0.5 1 1.5 2.0 Figure P4.1

An amplifier has a gain of 5 and the output waveform shown in Fig. P4.2. Sketch the input waveform. o (V) t (ms) 2 5 6 10 12 4 12 8 6 4 2 10 0 1 23456789 Figure P4.2

An op-amp based amplifier has supply voltages of 5 V and a gain of 20. (a) Sketch the input waveform from the output waveform in Fig. P4.3. (b) Double the amplitude of your results in (a) and sketch the new output waveform. o (V) t (ms) 1 3 2 3 2 1 0 25 50 75 100 125 Figure P4.3

For an ideal op-amp, the voltage gain and input resistance are infinite while the output resistance is zero. What are the consequences for (a) the op-amps input voltage? (b) the op-amps input currents? (c) the op-amps output current?

Revisit your answers in Problem 4.4 under the following nonideal scenarios. (a) Rin = , Rout = 0, Ao . (b) Rin = , Rout > 0, Ao = . (c) Rin , Rout = 0, Ao = .

Revisit the exact analysis of the inverting configuration in Section 4.3. (a) Find an expression for the gain if Rin = , Rout = 0, and Ao . (b) Plot the ratio of the gain in (a) to the ideal gain versus Ao for 1 Ao 1000 for an ideal gain of 10. (c) From your plot, does the actual gain approach the ideal value as Ao increases or decreases? (d) From your plot, what is the minimum value of Ao if the actual gain is within 5% of the ideal case?

Revisit the exact analysis of the inverting amplifier in Section 4.3. (a) Find an expression for the voltage gain if Rin , Rout = 0, and Ao . (b) For R2 = 27 k and R1 = 3 k, plot the ratio of the actual gain to the ideal gain for Ao = 1000 and 1 k Rin 100 k. (c) From your plot, does the ratio approach unity as Rin increases or decreases? (d) From your plot in (b), what is the minimum value of Rin if the gain ratio is to be at least 0.98?

An op-amp based amplifier has 18 V supplies and a gain of 80. Over what input range is the amplifier linear?

Assuming an ideal op-amp, determine the voltage gain of the circuit in Fig. P4.9. 20 k 1 k + o 1 + + Figure P4.9

Assuming an ideal op-amp, determine the voltage gain of the circuit in Fig. P4.10. o 1 + + 4 k 2 k 200 k + Figure P4.10

Assuming an ideal op-amp in Fig. P4.11, determine the value of RX that will produce a voltage gain of 26. + o + 1 + 4 k RX Figure P4.11

Assuming an ideal op-amp, find the voltage gain of the network in Fig. P4.12. 9 k 100 150 18 k + o + 1 + Figure P4.12

Assuming an ideal op-amp in Fig. P4.13, determine the output voltage Vo. 2 k 4 k 1 k 6 V 2 V + Vo + + + Figure P4.13

Determine the gain of the amplifier in Fig. P4.14. What is the value of Io? Vo Io Vin R2 R1 + Figure P4.14

For the amplifier in Fig. P4.15, find the gain and Io. Vo VS Io R2 R1 + Figure P4.15

Using the ideal op-amp assumptions, determine the values of Vo and I1 in Fig. P4.16. 11 V 1 k 10 k I1 Vo + Figure P4.16

Using the ideal op-amp assumptions, determine I1, I2, and I3 in Fig. P4.17. 1 mA R1 I2 I1 R2 Vo I3 + Figure P4.17

In a useful application, the amplifier drives a load. The circuit in Fig. P4.18 models this scenario. (a) Sketch the gain VoVS for 10 RL . (b) Sketch Io for 10 RL if VS = 0.1 V. (c) Repeat (b) if VS = 1.0 V. (d) What is the minimum value of RL if Io must be less than 100 mA for VS < 0.5 V? (e) What is the current IS if RL is 100 ? Repeat for RL = 10 k. VS Io IS Vo R2 R1 RL + Figure P4.18

The op-amp in the amplifier in Fig. P4.19 operates with 15 V supplies and can output no more than 200 mA. What is the maximum gain allowable for the amplifier if the maximum value of VS is 1 V? VS Vo R2 RL 50 R1 + Figure P4.19

For the amplifier in Fig. P4.20, the maximum value of VS is 2 V and the op-amp can deliver no more than 100 mA. (a) If 10 V supplies are used, what is the maximum allowable value of R2? (b) Repeat for 3 V supplies. (c) Discuss the impact of the supplies on the maximum allowable gain

For the circuit in Fig. P4.21, (a) find Vo in terms of V1 and V2. (b) If V1 = 2 V and V2 = 6 V, find Vo. (c) If the op-amp supplies are 12 V, and V1 = 4 V, what is the allowable range of V2? Vo V1 V2 2 k 2 k 1 k + Figure P4.21

Find Vo in the circuit in Fig. P4.22, assuming that the op-amp is ideal. + Vo + 1 V 1 k 5 k + Figure P4.22

The network in Fig. P4.23 is a current-to-voltage converter or transconductance amplifier. Find oiS for this network. i S 1 o + + Figure P4.23

Calculate the transfer function io1 for the network shown in Fig. P4.24. i o 1 RI RF + Figure P4.24

Determine the relationship between 1 and io in the circuit shown in Fig. P4.25. RF RI i o 1 + Figure P4.25

Find Vo in the network in Fig. P4.26 and explain what effect R1 has on the output. + 2 2 V 10 10 R1 Vo + + Figure P4.26

Determine the expression for o in the network in Fig. P4.27. + A B R1 R2 o Figure P4.27

Show that the output of the circuit in Fig. P4.28 is Vo = [ 1 + R2 R1 ]V1 R2 R1 V2 R3 R2 R1 R4 Vo V2 V1 + Figure P4.28

Find Vo in the network in Fig. P4.29. + + R1 1 k 5 V 4 k 4 V Vo + + Figure P4.29

Find the voltage gain of the op-amp circuit shown in Fig. P4.30. + V1 20 k 80 k 24 k Vo 1 k + + Figure P4.30

Determine the relationship between o and in in the circuit in Fig. P4.31. RI RF o R2 R1 in + Figure P4.31

In the network in Fig. P4.32, derive the expression for o in terms of the inputs 1 and 2. 1 R1 R2 RI RF o 2 + Figure P4.32

For the circuit in Fig. P4.33, find the value of R1 that produces a voltage gain of 10. + V1 R1 18 k Vo + + Figure P4.33

Find Vo in the circuit in Fig. P4.34. + + 40 k 5 k 5 k 5 V 4 V 20 k Vo + + Figure P4.34

Find Vo in the circuit in Fig. P4.35. + + + + 40 k 30 k 100 k 12 V 10 V 9 V 10 k 20 k 20 k 6 V Vo + + Figure P4.35

Determine the expression for the output voltage, o, of the inverting-summer circuit shown in Fig. P4.36. RF o R1 1 2 3 R2 R3 + Figure P4.36

Determine the output voltage, o, of the noninverting averaging circuit shown in Fig. P4.37. RF RI o R1 1 2 3 R2 R3 + Figure P4.37

Find the input/output relationship for the current amplifier shown in Fig. P4.38. RL RF RI i o i in + + Figure P4.38

Find Vo in the circuit in Fig. P4.39. + 80 k 40 k Vo 40 k 20 k 10 k 5 V + + + Figure P4.39

Find o in the circuit in Fig. P4.40. o 2 1 R2 R2 R1 R1 + + Figure P4.40

Find the expression for o in the differential amplifier circuit shown in Fig. P4.41. o 2 1 R1 R1 RF R1 R1 + + Figure P4.41

Find o in the circuit in Fig. P4.42. o 1 R2 R3 R4 R1 + Figure P4.42

Find the output voltage, o, in the circuit in Fig. P4.43. o 1 2 R3 R3 R4 R4 R1 R2 R2 + + + Figure P4.43

The electronic ammeter in Example 4.7 has been modified and is shown in Fig. P4.44. The selector switch allows the user to change the range of the meter. Using values for R1 and R2 from Example 4.7, find the values of RA and RB that will yield a 10-V output when the current being measured is 100 mA and 10 mA, respectively. Vo + + + I Unknown current Selector switch Voltmeter R1 = 1 k RA RB RC = 1 k R2 = 9 k Figure P4.44