Chapter 17 Self Test: Negative Feedback - Electronics Principles by Malvino/Bates

With negative feedback, the returning signal a. Aids the input signal b. Opposes the input signal c. Is proportional to output current d. Is proportional to differential voltage gain

b

How many types of negative feedback are there? a. One b. Two c. Three d. Four

d

A VCVS amplifier approximates an ideal a. Voltage amplifier b. Current-to-voltage converter c. Voltage-to-current converter d. Current amplifier

a

The voltage between the input terminals of an ideal op amp is a. Zero b. Very small c. Very large d. Equal to the input voltage

a

When an op amp is not saturated, the voltages at the noninverting and inverting inputs are a. Almost equal b. Much different c. Equal to the output voltage d. Equal to ±15 V

a

The feedback fraction B a. Is always less than 1 b. Is usually greater than 1 c. May equal 1 d. May not equal 1

c

An ICVS amplifier has no output voltage. A possible trouble is a. No negative supply voltage b. Shorted feedback resistor c. No feedback voltage d. Open load resistor

b

In a VCVS amplifier, any decrease in open-loop voltage gain produces an increase in a. Output voltage b. Error voltage c. Feedback voltage d. Input voltage

b

The open-loop voltage gain equals the a. Gain with negative feedback b. Differential voltage gain of the op amp c. Gain when B is 1 d. Gain at funity

b

The loop gain AVOLB a. Is usually much smaller than 1 b. Is usually much greater than 1 c. May not equal 1 d. Is between 0 and 1

b

The closed-loop input impedance with an ICVS amplifier is a. Usually larger than the open-loop input impedance b. Equal to the open-loop input impedance c. Sometimes less than the open-loop impedance d. Ideally zero

d

With an ICVS amplifier, the circuit approximates an ideal a. Voltage amplifier b. Current-to-voltage converter c. Voltage-to-current converter d. Current amplifier

b

Negative feedback reduces a. The feedback fraction b. Distortion c. The input offset voltage d. The open-loop gain

b

A voltage follower has a voltage gain of a. Much less than 1 b. 1 c. More than 1 d. AVOL

b

The voltage between the input terminals of a real op amp is a. Zero b. Very small c. Very large d. Equal to the input voltage

b

The transresistance of an amplifier is the ratio of its a. Output current to input voltage b. Input voltage to output current c. Output voltage to input voltage d. Output voltage to input current

d

Current cannot flow to ground through a. A mechanical ground b. An ac ground c. A virtual ground d. An ordinary ground

c

In a current-to-voltage converter, the input current flows a. Through the input impedance of the op amp b. Through the feedback resistor c. To ground d. Through the load resistor

b

The input impedance of a current-to-voltage converter is a. Small b. Large c. Ideally zero d. Ideally infinite

c

The open-loop bandwidth equals a. funity b. f2(OL) c. funity/Av(CL) d. fmax

b

The closed-loop bandwidth equals a. funity b. f2(OL) c. funity/Av(CL) d. fmax

c

For a given op amp, which of these is constant? a. f2(OL) b. Feedback voltage c. Av(CL) d. Av(CL)f(CL)

d

Negative feedback does not improve a. Stability of voltage gain b. Nonlinear distortion in later stages c. Output offset voltage d. Power bandwidth

d

An ICVS amplifier is saturated. A possible trouble is a. No supply voltages b. Open feedback resistor c. No input voltage d. Open load resistor

b

A VCVS amplifier has no output voltage. A possible trouble is a. Shorted load resistor b. Open feedback resistor c. Excessive input voltage d. Open load resistor

a

An ICIS amplifier is saturated. A possible trouble is a. Shorted load resistor b. R2 is open c. No input voltage d. Open load resistor

b

An ICVS amplifier has no output voltage. A possible trouble is a. No positive supply voltage b. Open feedback resistor c. No feedback voltage d. Shorted load resistor

d

The closed-loop input impedance in a VCVS amplifier is a. Usually larger than the open-loop input impedance b. Equal to the open-loop input impedance c. Sometimes less than the open-loop input impedance d. Ideally zero

a