Floyd Self-test Chapter 12 Topic Outline
- Floyd Self-test in Introduction to Operational Amplifiers
- Floyd Self-test in Op-Amp Input Modes and Parameters
- Floyd Self-test in Negative Feedback
- Floyd Self-test in Op-Amps with Negative Feedback
- Floyd Self-test in Effects of Negative Feedback on Op-Amp Impedances
- Floyd Self-test in Bias Current and Offset Voltage
- Floyd Self-test in Open-Loop Frequency and Phase Responses
- Floyd Self-test in Closed-Loop Frequency Response
Start Practice Exam Test Questions
Choose the letter of the best answer in each questions.
1. An integrated circuit (IC) op-amp has
- (a) two inputs and two outputs
- (b) one input and one output
- (c) two inputs and one output
2. Which of the following characteristics does not necessarily apply to an op-amp?
- (a) High gain
- (b) Low power
- (c) High input impedance
- (d) Low output impedance
3. A differential amplifier
- (a) is part of an op-amp
- (b) has one input and one output
- (c) has two outputs
- (d) answers (a) and (c)
4. When an op-amp is operated in the single-ended differential mode,
- (a) the output is grounded
- (b) one input is grounded and a signal is applied to the other
- (c) both inputs are connected together
- (d) the output is not inverted
5. In the double-ended differential mode,
- (a) a signal is applied between the two inputs
- (b) the gain is 1
- (c) the outputs are different amplitudes
- (d) only one supply voltage is used
6. In the common mode,
- (a) both inputs are grounded
- (b) the outputs are connected together
- (c) an identical signal appears on both inputs
- (d) the output signals are in-phase
7. Common-mode gain is
- (a) very high
- (b) very low
- (c) always unity
- (d) unpredictable
8. If Aol = 3500 and Acm = 0.35, the CMRR is
- (a) 1225
- (b) 10,000
- (c) 80 dB
- (d) answers (b) and (c)
9. With zero volts on both inputs, an op-amp ideally should have an output equal to
- (a) the positive supply voltage
- (b) the negative supply voltage
- (c) zero
- (d) the CMRR
10. Of the values listed, the most realistic value for open-loop gain of an op-amp is
- (a) 1
- (b) 2000
- (c) 80 dB
- (d) 100,000
11. A certain op-amp has bias currents of 50μA and 49.3μA. The input offset current is
- (a) 700 nA
- (b)99.3μA
- (c)49.7μA
- (d) none of these
12. The output of a particular op-amp increases 8 V in 12μs. The slew rate is
- (a) 96V/ μs
- (b)0.67V/ μs
- (c) 1.5V/ μs
- (d) none of these
13. The purpose of offset nulling is to
- (a) reduce the gain
- (b) equalize the input signals
- (c) zero the output error voltage
- (d) answers (b) and (c)
14. The use of negative feedback
- (a) reduces the voltage gain of an op-amp
- (b) makes the op-amp oscillate
- (c) makes linear operation possible
- (d) answers (a) and (c)
15. For an op-amp with negative feedback, the output is
- (a) equal to the input
- (b) increased
- (c) fed back to the inverting input
- (d) fed back to the noninverting input
16. A certain noninverting amplifier has an Ri of and an Rf of The closed-loop gain is
- (a) 100,000
- (b) 1000
- (c) 101
- (d) 100
17. If the feedback resistor in Question 16 is open, the voltage gain
- (a) increases
- (b) decreases
- (c) is not affected
- (d) depends on Ri
18. A certain inverting amplifier has a closed-loop gain of 25. The op-amp has an open-loop gain of 100,000. If another op-amp with an open-loop gain of 200,000 is substituted in the configuration, the closed-loop gain
- (a) doubles
- (b) drops to 12.5
- (c) remains at 25
- (d) increases slightly
19. A voltage-follower
- (a) has a gain of 1
- (b) is noninverting
- (c) has no feedback resistor
- (d) has all of these
20. Negative feedback
- (a) increases the input and output impedances
- (b) increases the input impedance and the bandwidth
- (c) decreases the output impedance and the bandwidth
- (d) does not affect impedances or bandwidth
21. Bias current compensation
- (a) reduces gain
- (b) reduces output error voltage
- (c) increases bandwidth
- (d) has no effect
22. The midrange open-loop gain of an op-amp
- (a) extends from the lower critical frequency to the upper critical frequency
- (b) extends from 0 Hz to the upper critical frequency
- (c) rolls off at 20 dB/decade beginning at 0 Hz
- (d) answers (b) and (c)
23. The frequency at which the open-loop gain is equal to 1 is called
- (a) the upper critical frequency
- (b) the cutoff frequency
- (c) the notch frequency
- (d) the unity-gain frequency
24. Phase shift through an op-amp is caused by
- (a) the internal RC circuits
- (b) the external RC circuits
- (c) the gain roll-off
- (d) negative feedback
25. Each RC circuit in an op-amp
- (a) causes the gain to roll off at
- (b) causes the gain to roll off at
- (c) reduces the midrange gain by 3 dB
- (d) answers (a) and (b)
26. If a certain op-amp has a midrange open-loop gain of 200,000 and a unity-gain frequency of 5 MHz, the gain-bandwidth product is
- (a) 200,000 Hz
- (b) 5,000,000 Hz
- (c) 1 x 1012 Hz
- (d) not determinable from the information
27. The bandwidth of an ac amplifier having a lower critical frequency of 1 kHz and an upper critical frequency of 10 kHz is
- (a) 1 kHz
- (b) 9 kHz
- (c) 10 kHz
- (d) 11 kHz
28. The bandwidth of a dc amplifier having an upper critical frequency of 100 kHz is
- (a) 100 kHz
- (b) unknown
- (c) infinity
- (d) 0 kHz
29. When negative feedback is used, the gain-bandwidth product of an op-amp
- (a) increases
- (b) decreases
- (c) stays the same
- (d) fluctuates
30. If a certain op-amp has a closed-loop gain of 20 and an upper critical frequency of 10 MHz, the gain-bandwidth product is
- (a) 200 MHz
- (b) 10 MHz
- (c) the unity-gain frequency
- (d) answers (a) and (c)
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