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  • Question
  • With negative feedback, the returning signal


  • Options
  • A. is proportional to the output current
  • B. is proportional to the differential voltage gain
  • C. opposes the input signal
  • D. aids the input signal

  • Correct Answer
  • opposes the input signal 


  • Operational Amplifiers problems


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    • 1. The input offset current equals the

    • Options
    • A. average of two base currents
    • B. collector current divided by the current gain
    • C. difference between two base-emitter voltages
    • D. difference between two base currents
    • Discuss
    • 2. 

      Decreasing the gain in the given circuit could be achieved by


    • Options
    • A. reducing the amplitude of the input voltage
    • B. increasing the value of the feedback resistor
    • C. increasing the value of the input resistor
    • D. removing the feedback resistor
    • Discuss
    • 3. A differential amplifier has a common-mode gain of 0.2 and a common-mode rejection ratio of 3250. What would the output voltage be if the single-ended input voltage was 7 mV rms?

    • Options
    • A. 1.4 mV rms
    • B. 650 mV rms
    • C. 4.55 V rms
    • D. 0.455 V rms
    • Discuss
    • 4. The major difference between ground and virtual ground is that virtual ground is only a:

    • Options
    • A. voltage reference
    • B. current reference
    • C. power reference
    • D. difference reference
    • Discuss
    • 5. The voltage follower has a:

    • Options
    • A. closed-loop voltage gain of unity
    • B. small open-loop voltage gain
    • C. closed-loop bandwidth of zero
    • D. large closed-loop output impedance
    • Discuss
    • 6. What is this circuit?


    • Options
    • A. a low-pass filter
    • B. a high-pass filter
    • C. a bandpass filter
    • D. a band-stop filter
    • Discuss
    • 7. What is the frequency of this 555 astable multivibrator?


    • Options
    • A. 278 Hz
    • B. 178 Hz
    • C. 78 Hz
    • D. 8 Hz
    • Discuss
    • 8. If the gain of a closed-loop inverting amplifier is 3.9, with an input resistor value of 1.6 kilohms, what value of feedback resistor is necessary?

    • Options
    • A. 6240 ohms
    • B. 2.4 kilohms
    • C. 410 ohms
    • D. 0.62 kilohms
    • Discuss
    • 9. When a capacitor is used in place of a resistor in an op-amp network, its placement determines:

    • Options
    • A. open- or closed-loop gain
    • B. integration or differentiation
    • C. saturation or cutoff
    • D. addition or subtraction
    • Discuss
    • 10. An output that is proportional to the addition of two or more inputs is from which type of amplifier?

    • Options
    • A. differentiator
    • B. difference
    • C. summing
    • D. analog subtractor
    • Discuss


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