ETC EngineeringMCQs
Home

Operational Amplifier Applications MCQs

Practice Operational Amplifier Applications MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 1
Analog ElectronicsOperational Amplifier Applications

A practical op-amp integrator often places a resistor in parallel with the feedback capacitor mainly to?

  • ALimit DC gain and reduce saturation from offsets
  • BIncrease DC gain to infinity
  • CRemove all negative feedback
  • DMake the circuit a comparator
Report an error
Correct Answer: A. Limit DC gain and reduce saturation from offsets
Explanation: The parallel resistor provides finite DC feedback, preventing tiny offsets and bias currents from integrating indefinitely and driving the output into saturation.
Reference: Standard analog electronics: practical integrator
Question 2
Analog ElectronicsOperational Amplifier Applications

A practical op-amp differentiator is commonly bandwidth-limited with additional resistive/capacitive components mainly because an ideal differentiator strongly amplifies?

  • AHigh-frequency noise
  • BDC only
  • CPower-supply current only
  • DCommon-mode voltage only
Report an error
Correct Answer: A. High-frequency noise
Explanation: The ideal differentiator's gain rises with frequency, making it highly sensitive to high-frequency noise and stability problems; practical designs limit this gain.
Reference: Standard analog electronics: practical differentiator
Question 3
Analog ElectronicsOperational Amplifier Applications

A precision rectifier using an op-amp is useful for small signals mainly because feedback can?

  • ACompensate much of the ordinary diode forward-drop error
  • BMake diode current exactly zero
  • CConvert every signal to digital form
  • DEliminate the need for a power supply
Report an error
Correct Answer: A. Compensate much of the ordinary diode forward-drop error
Explanation: Placing the diode within an op-amp feedback arrangement allows accurate rectification of signals much smaller than a normal diode's forward drop.
Reference: Standard analog electronics: precision rectifier
Question 4
Analog ElectronicsOperational Amplifier Applications

A transimpedance amplifier is designed primarily to convert?

  • AInput current into output voltage
  • BInput voltage into output frequency
  • CResistance into inductance
  • DDigital code into current only
Report an error
Correct Answer: A. Input current into output voltage
Explanation: With current applied to the inverting summing node, the feedback resistor produces an output voltage proportional to input current.
Reference: Standard analog electronics: transimpedance amplifier
Question 6
Analog ElectronicsOperational Amplifier Applications

A logarithmic amplifier commonly uses a diode or transistor junction in its feedback path because the junction has an approximately?

  • AExponential current-voltage characteristic
  • BPerfectly linear resistance
  • CInfinite breakdown voltage
  • DConstant current independent of voltage
Report an error
Correct Answer: A. Exponential current-voltage characteristic
Explanation: The exponential junction law allows an op-amp feedback circuit to produce an output proportional to the logarithm of input current or voltage.
Reference: Standard analog electronics: logarithmic amplifier
Question 7
Analog ElectronicsOperational Amplifier Applications

An antilog amplifier produces an output related approximately to?

  • AThe exponential of its input
  • BThe derivative of its input only
  • CThe average of two supplies
  • DA fixed digital code
Report an error
Correct Answer: A. The exponential of its input
Explanation: By placing an exponential junction in the input path and using linear feedback, the circuit can generate an exponential, or antilogarithmic, transfer.
Reference: Standard analog electronics: antilog amplifier
Question 8
Analog ElectronicsOperational Amplifier Applications

An ideal peak detector using an op-amp, diode and capacitor is intended to hold approximately?

  • AThe maximum value reached by the input waveform
  • BThe RMS value of every waveform automatically
  • COnly the zero crossing
  • DThe input frequency as a voltage
Report an error
Correct Answer: A. The maximum value reached by the input waveform
Explanation: The diode-capacitor feedback arrangement charges the storage capacitor to the input peak and ideally holds that level between larger peaks.
Reference: Standard analog electronics: peak detector
Question 9
Analog ElectronicsOperational Amplifier Applications

In a practical peak detector, a high input-resistance buffer after the hold capacitor is useful mainly to?

  • AReduce discharge of the stored voltage by the load
  • BIncrease diode forward drop
  • CForce the capacitor to discharge immediately
  • DCreate positive feedback oscillation
Report an error
Correct Answer: A. Reduce discharge of the stored voltage by the load
Explanation: A buffer isolates the storage capacitor from the load, reducing loading and helping the held peak voltage decay more slowly.
Reference: Standard analog electronics: buffered peak detector
Question 10
Analog ElectronicsOperational Amplifier Applications

A full-wave precision rectifier is especially useful when the input amplitude is?

  • AComparable to or smaller than an ordinary diode forward drop
  • BAlways hundreds of volts
  • CExactly zero only
  • DA digital logic level only
Report an error
Correct Answer: A. Comparable to or smaller than an ordinary diode forward drop
Explanation: Op-amp feedback compensates much of the diode threshold error, allowing accurate rectification of low-level analog signals.
Reference: Standard analog electronics: full-wave precision rectifier