# Floyd Self-test in Basic Op-Amp Circuits

(Last Updated On: December 8, 2017)

This is the Self-test in Chapter 13: Basic Op-Amp Circuits from the book Electronic Devices Conventional Current Version, 9th edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

### Floyd Self-test Chapter 13 Topic Outline

• Floyd Self-test in Comparators
• Floyd Self-test in Summing Amplifiers
• Floyd Self-test in Integrators and Differentiators

### Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. In a zero-level detector, the output changes state when the input

• (a) is positive
• (b) is negative
• (c) crosses zero
• (d) has a zero rate of change

2. The zero-level detector is one application of a

• (a) comparator
• (b) differentiator
• (c) summing amplifier
• (d) diode

3. Noise on the input of a comparator can cause the output to

• (a) hang up in one state
• (b) go to zero
• (c) change back and forth erratically between two states
• (d) produce the amplified noise signal

4. The effects of noise can be reduced by

• (a) lowering the supply voltage
• (b) using positive feedback
• (c) using negative feedback
• (d) using hysteresis
• (e) answers (b) and (d)

5. A comparator with hysteresis

• (a) has one trigger point
• (b) has two trigger points
• (c) has a variable trigger point
• (d) is like a magnetic circuit

6. In a comparator with hysteresis,

• (a) a bias voltage is applied between the two inputs
• (b) only one supply voltage is used
• (c) a portion of the output is fed back to the inverting input
• (d) a portion of the output is fed back to the noninverting input

7. Using output bounding in a comparator

• (a) makes it faster
• (b) keeps the output positive
• (c) limits the output levels
• (d) stabilizes the output

8. A summing amplifier can have

• (a) only one input
• (b) only two inputs
• (c) any number of inputs

9. If the voltage gain for each input of a summing amplifier with a feedback resistor is unity, the input resistors must have a value of

• (a) 4.7kΩ
• (b) 4.7kΩ divided by the number of inputs
• (c) 4.7kΩ times the number of inputs

10. An averaging amplifier has five inputs. The ratio Rf /R must be

• (a) 5
• (b) 0.2
• (c) 1

11. In a scaling adder, the input resistors are

• (a) all the same value
• (b) all of different values
• (c) each proportional to the weight of its input
• (d) related by a factor of two

12. In an ideal integrator, the feedback element is a

• (a) resistor
• (b) capacitor
• (c) zener diode
• (d) voltage divider

13. For a step input, the output of an integrator is

• (a) a pulse
• (b) a triangular waveform
• (c) a spike
• (d) a ramp

14. The rate of change of an integrator’s output voltage in response to a step input is set by

• (a) the RC time constant
• (b) the amplitude of the step input
• (c) the current through the capacitor
• (d) all of these

15. In a differentiator, the feedback element is a

• (a) resistor
• (b) capacitor
• (c) zener diode
• (d) voltage divider

16. The output of a differentiator is proportional to

• (a) the RC time constant
• (b) the rate at which the input is changing
• (c) the amplitude of the input
• (d) answers (a) and (b)

17. When you apply a triangular waveform to the input of a differentiator, the output is

• (a) a dc level
• (b) an inverted triangular waveform
• (c) a square waveform
• (d) the first harmonic of the triangular waveform