Electronic Devices-Operational Amplifiers
Electronic Devices-Operational Amplifiers
31. The midrange open-loop gain of an op-amp is 135 dB. With negative feedback this gain is reduced to 72 dB. The closed-loop gain is
- 135 dB.
- 72 dB.
- 207 dB.
- 63 dB.
32. What is the level of the current through the amplifier input(s) to ground in an op-amp?
- Virtually zero
- 1.7 mA
- 2.8 mA
- 3.3 mA
33. Open-loop voltage gain of an op-amp can range up to ________.
- 10,000
- 50,000
- 100,000
- 200,000
34. At what input voltage level does the output voltage level become numerically equal to the value of the common-mode gain of the amplifier?
- Vi1 = –Vi2 = 0.25 V
- Vi1 = –Vi22 = 0.50 V
- Vi1 = –Vi2 = 0.75 V
- Vi1 = –Vi2 = 1.00 V
35. Which of the following is (are) the result of gain reduction by a feedback?
- The amplifier voltage gain is a more stable and precise value.
- The input impedance of the circuit is increased over that of the op-amp alone.
- The output impedance is reduced over that of the op-amp alone.
- All of the above
36. An inverting amplifier has an input impedance equal to the feedback resistor Rf.
- TRUE
- FALSE
38. Negative feedback decreases the bandwidth and increases the voltage gain.
- TRUE
- FALSE
39. A good op-amp has low voltage gain, low output impedance, and high input impedance.
- TRUE
- FALSE
40. A non-inverting amplifier has a higher input impedance and a lower output impedance than the op-amp itself (without feedback).
- TRUE
- FALSE