In this section of Electronic Devices and Circuits.It contain Operational Amplifiers (OP AMPS) MCQs (Multiple Choice Questions Answers).All the MCQs (Multiple Choice Question Answers) requires in depth reading of Electronic Devices and Circuits Subject as the hardness level of MCQs have been kept to advance level.These Sets of Questions are very helpful in Preparing for various Competitive Exams and University level Exams.

**This Section covers below lists of topics :**

- Operational Amplifiers MCQs.
- OP AMPS as voltage amplifiers,inverting ,Non-inverting,The voltage follower,The Summing Amplifier,The Differential amplifier MCQs.
- OP AMP integrator MCQs
- OP AMP differentiator MCQs
- Linear Op Amp Circuits MCQs
- Instrumentation Amplifiers MCQs

**Practice it now to sharpen your concept.**

#### 1. OPAMP is a/an:

- Differential amplifier
- Oscillator
- Rectifier
- None of the above

#### 2. OPAMP operates at:

- High voltage (~ 100 KV)
- Medium voltage (~ 220 Volt)
- Low voltage (~ 12 Volt)
- Very high voltage (~ 10 mili Volt)

#### 3. Voltage gain of an ideal op-amp is:

- Infinite
- Very high
- Low
- Very low

#### 4. Bandwidth of an ideal op-amp is:

- Infinite
- Very high
- Low
- Very low

#### 5. Output impedance of an ideal op-amp is:

- Infinite
- Very high
- Low
- Zero

#### 6. CMRR of an ideal op-amp is:

- Infinite
- Very high
- Low
- Very low

#### 7. Slew rate of an ideal op-amp is:

- Infinite
- Very high
- Low
- Zero

#### 8. Op-amp is a:

- Voltage-controlled voltage source (VCVS)
- Voltage-controlled current source (VCCS)
- Current-controlled voltage source (CCVS)
- Current-controlled current source (CCCS)

#### 9. Op-Amp uses:

- Only +ve Voltage
- Only –ve voltage
- Dual supply, i.e., ± Vcc
- None of the above

#### 10. Virtual ground of an op-amp means:

- Terminal is grounded directly
- The terminal is not physically grounded but terminal voltage is zero due to the other terminal is connected to the ground due to op-amp properties.
- Both (a) and (b)
- None of the above

#### 11. Op-Amp uses:

- Negative feedback
- Positive feedback
- Both of the above
- None of the above

#### 12. Common-mode gain signifies:

- The ability to reject the common mode signals like noise and interference
- Increase the noise
- Increase the distortion
- All of the above

#### 13. Slew rate is defined as the:

- Maximum rate of change of output voltage with time
- Minimum rate of change of output voltage with time
- Moderate rate of change of output voltage with time
- None of the above

#### 14. Op-amp integrator uses:

- Capacitor as feedback element
- Resistor as feedback element
- Inductor as feedback element
- A simple wire as feedback element

#### 15. The op amp can amplify

- AC signals only
- DC signals only
- Both ac and dc signals
- Neither ac nor dc signals

#### 16. The tail current of a diff amp is

- Half of either collector current
- Equal to either collector current
- Two times either collector current
- Equal to the difference in base currents

#### 17. The node voltage at the top of the tail resistor is closest to

- Collector supply voltage
- Zero
- Emitter supply voltage
- Tail current times base resistance

#### 18. The input offset current equals the

- Difference between two base currents
- Average of two base currents
- Collector current divided by current gain
- Difference between two base-emitter voltages

#### 19. The tail current equals the

- Difference between two emitter currents
- Sum of two emitter currents
- Collector current divided by current gain
- Collector voltage divided by collector resistance

#### 20. The voltage gain of a diff amp with a differential output is equal to RC divided by

- re’
- re’/2
- 2re’
- RE

#### 21. The input impedance of a differential amplifier equals re’ times

- 0
- RC
- RE
- 2 times Beta

#### 22. A dc signal has a frequency of

- 0
- 60 Hz
- 0 to over 1 MHz
- 1 MHz

#### 23. When the two input terminals of a diff amp are grounded,

- The base currents are equal
- The collector currents are equal
- An output error voltage usually exists
- The ac output voltage is zero

#### 24. One source of output error voltage is

- Input bias current
- Difference in collector resistors
- Tail current
- Common-mode voltage gain

#### 25. A common-mode signal is applied to

- The non-inverting input
- The inverting input
- Both inputs
- Top of the tail resistor

#### 26. The common-mode voltage gain is

- Smaller than voltage gain
- Equal to voltage gain
- Greater than voltage gain
- None of the above

#### 27. The input stage of an op amp is usually a

- Differential amplifier
- Class B push-pull amplifier
- CE amplifier
- Swamped amplifier

#### 28. The tail of a diff amp acts like a

- Battery
- Current source
- Transistor
- Diode

#### 29. The common-mode voltage gain of a diff amp is equal to RC divided by

- re’
- re’/2
- 2re’
- 2RE

#### 30. When the two bases are grounded in a diff amp, the voltage across each emitter diode is

- Zero
- 0.7 V
- The same
- High

#### 31. The common-mode rejection ratio is

- Very low
- Often expressed in decibels
- Equal to the voltage gain
- Equal to the common-mode voltage gain

#### 32. The typical input stage of an op amp has a

- Single-ended input and single-ended output
- Single-ended input and differential output
- Differential input and single-ended output
- Differential input and differential output

#### 33. The input offset current is usually

- Less than the input bias current
- Equal to zero
- Less than the input offset voltage
- Unimportant when a base resistor is used

#### 34. With both bases grounded, the only offset that produces an error is the

- Input offset current
- Input bias current
- Input offset voltage
- Beta

#### 35. What usually controls the open-loop cutoff frequency of an op amp?

- Stray-wiring capacitance
- Base-emitter capacitance
- Collector-base capacitance
- Compensating capacitance

#### 36. A compensating capacitor prevents

- Voltage gain
- Oscillations
- Input offset current
- Power bandwidth

#### 37. At the unity-gain frequency, the open-loop voltage gain is

- 1
- Amid
- Zero
- Very large

#### 38. The cutoff frequency of an op amp equals the unity-gain frequency divided by

- the cutoff frequency
- Closed-loop voltage gain
- Unity
- Common-mode voltage gain

#### 39. If the cutoff frequency is 15 Hz and the midband open-loop voltage gain is 1,000,000, the unity-gain frequency is

- 25 Hz
- 1 MHz
- 1.5 MHz
- 15 MHz

#### 40. The input impedance of an ideal op amp is

- Finite
- 0
- Infinite
- Unity

#### 41. If the unity-gain frequency is 5 MHz and the midband open loop voltage gain is 200,000, the cutoff frequency is

- 25 Hz
- 1 MHz
- 1.5 MHz
- 15 MHz

#### 42. An op-AMP is a device having the following number of input terminals

- 1
- 2
- 3
- 4

#### 43. The initial slope of a sine wave is directly proportional to

- Slew rate
- Frequency
- Voltage gain
- Capacitance

#### 44. The gain of an inverting amplifier is given as

- R2/R1
- R1/R2
- -R1/R2
- R1/(R1+R2)

#### 45. When the initial slope of a sine wave is greater than the slew rate,

- Distortion occurs
- Linear operation occurs
- Voltage gain is maximum
- The op amp works best

#### 46. AN OP-AMP can be used to generate the waveform having shape

- Square
- Pulse
- Triangular
- All of these

#### 47. The power bandwidth increases when

- Frequency decreases
- Frequency decreases
- Initial slope decreases
- Voltage gain increases

#### 48. The gain of an op-amp voltage follower is

- 0
- Unity
- Infinite
- Very high

#### 49. A 741C uses

- Discrete resistors
- Inductors
- Active-load resistors
- A large coupling capacitor

#### 50. A 741C cannot work without

- Discrete resistors
- Passive loading
- Dc return paths on the two bases
- A small coupling capacitor

#### 51. The input impedance of a BIFET op amp is

- Low
- Medium
- High
- Extremely high

#### 52. An LF157A is a

- Diff amp
- Source follower
- Bipolar op amp
- BIFET op amp

#### 53. If the two supply voltages are plus and minus 15 V, the MPP value of an op amp is closest to

- 0
- +15V
- -15 V
- 30 V

#### 54. The open-loop cutoff frequency of a 741C is controlled by

- A coupling capacitor
- The output short circuit current
- The power bandwidth
- A compensating capacitor

#### 55. The 741C has a unity-gain frequency of

- 10 Hz
- 20 kHz
- 1 MHz
- 15 MHz

#### 56. The unity-gain frequency equals the product of closed-loop voltage gain and the

- Compensating capacitance
- Tail current
- Closed-loop cutoff frequency
- Load resistance

#### 57. If the unity frequency is 10 MHz and midband open-loop voltage gain is 1,000,000, then the open-loop cutoff frequency of the op amp is

- 10 Hz
- 20 Hz
- 50 Hz
- 100 Hz

#### 58. The initial slope of a sine wave increases when

- Frequency decreases
- Peak value increases
- Cc increases
- Cc increases

#### 59. If the frequency is greater than the power bandwidth,

- Slew-rate distortion occurs
- A normal output signal occurs
- Output offset voltage increases
- Distortion may occur

#### 60. An op amp has an open base resistor. The output voltage will be

- Zero
- Slightly different from zero
- Maximum positive or negative
- An amplified sine wave

#### 61. An op amp has a voltage gain of 500,000. If the output voltage is 1 V, the input voltage is

- 2 microvolts
- 5 mV
- 10 mV
- 1 V

#### 62. A 741C has supply voltages of plus and minus 15 V. If the load resistance is large, the MPP value is

- 0
- +15 V
- 27 V
- 27 V

#### 63. Above the cutoff frequency, the voltage gain of a 741C decreases approximately

- 10 dB per decade
- 20 dB per octave
- 10 dB per octave
- 20 dB per decade

#### 64. The voltage gain of an op amp is unity at the

- Cutoff frequency
- Unity-gain frequency
- Generator frequency
- Power bandwidth

#### 65. When slew-rate distortion of a sine wave occurs, the output

- Is larger
- Appears triangular
- Is normal
- Has no offset

#### 66. A 741C has

- A voltage gain of 100,000
- An input impedance of 2 Mohm
- An output impedance of 75 ohm
- All of the above

#### 67. The closed-loop voltage gain of an inverting amplifier equals

- The ratio of the input resistance to the feedback resistance
- The open-loop voltage gain
- The feedback resistance divided by the input resistance
- The input resistance

#### 68. The non-inverting amplifier has a

- Large closed-loop voltage gain
- Small open-loop voltage gain
- Large closed-loop input impedance
- Large closed-loop output impedance

#### 69. The voltage follower has a

- Closed-loop voltage gain of unity
- Small open-loop voltage gain
- Closed-loop bandwidth of zero
- Large closed-loop output impedance

#### 70. A summing amplifier can have

- No more than two input signals
- Two or more input signals
- A closed-loop input impedance of infinity
- A small open-loop voltage gain

#### 71. In a linear op-amp circuit, the

- Signals are always sine waves
- Op amp does not go into saturation
- Input impedance is ideally infinite
- Gain-bandwidth product is constant

#### 72. In an ac amplifier using an op amp with coupling and bypass capacitors, the output offset voltage is

- Zero
- Minimum
- Maximum
- Unchanged

#### 73. To use an op amp, you need at least

- One supply voltage
- Two supply voltages
- One coupling capacitor
- One bypass capacitor

#### 74. In a controlled current source with op amps, the circuit acts like a

- Voltage amplifier
- Current-to-voltage converter
- Voltage-to-current converter
- Current amplifier

#### 75. An instrumentation amplifier has a high

- Output impedance
- Power gain
- CMRR
- Supply voltage

#### 76. A current booster on the output of an op amp will increase the short-circuit current by

- ACL
- Beta dc
- funity
- Av

#### 77. Given a voltage reference of +2.5 V, we can get a voltage reference of +15 V by using a

- Inverting amplifier
- Noninverting amplifier
- Differential amplifier
- Instrumentation amplifier

#### 78. In a differential amplifier, the CMRR is limited mostly by

- CMRR of the op amp
- Gain-bandwidth product
- Supply voltages
- Tolerance of resistors

#### 79. The input signal for an instrumentation amplifier usually comes from

- An inverting amplifier
- A transducer
- A differential amplifier
- A Wheatstone bridge

#### 80. In the classic three op-amp instrumentation amplifier, the differential voltage gain is usually produced by the

- First stage
- Second stage
- Mismatched resistors
- Output op amp

#### 81. Guard driving reduces the

- CMRR of an instrumentation amplifier
- Leakage current in the shielded cable
- Voltage gain of the first stage
- Common-mode input voltage

#### 82. In an averaging circuit, the input resistances are

- Equal to the feedback resistance
- Equal to the feedback resistance
- Greater than the feedback resistance
- Unequal to each other

#### 83. A D/A converter is an application of the

- Adjustable bandwidth circuit
- Noninverting amplifier
- Voltage-to-current converter
- Summing amplifier

#### 84. In a voltage-controlled current source,

- A current booster is never used
- The load is always floated
- A stiff current source drives the load
- The load current equals ISC

#### 85. The Howland current source produces a

- Unidirectional floating load current
- Bidirectional single-ended load current
- Unidirectional single-ended load current
- Bidirectional floating load current

#### 86. The purpose of AGC is to

- Increase the voltage gain when the input signal increases
- Convert voltage to current
- Keep the output voltage almost constant
- Reduce the CMRR of the circuit

#### 87. 1 ppm is equivalent to

- 0.1%
- 0.01%
- 0.001%
- 0.0001%

#### 88. An input transducer converts

- Voltage to current
- Current to voltage
- An electrical quantity to a nonelectrical quantity
- A nonelectrical quantity to an electrical quantity

#### 89. A thermistor converts

- Light to resistance
- Temperature to resistance
- Voltage to sound
- Current to voltage

#### 90. When we trim a resistor, we are

- Making a fine adjustment
- Reducing its value
- Increasing its value
- Making a coarse adjustment

#### 91. A D/A converter with four inputs has

- Two outputs
- Four outputs
- Eight outputs
- Sixteen outputs

#### 92. An op amp with a rail-to-rail output

- Has a current-boosted output
- Can swing all the way to either supply voltage
- Has a high output impedance
- Cannot be less than 0 V.

#### 93. When a JFET is used in an AGC circuit, it acts like a

- Switch
- Voltage-controlled current source
- Voltage-controlled resistance
- Capacitance

#### 94. If an op amp has only a positive supply voltage, its output cannot

- Be negative
- Be zero
- Equal the supply voltage
- Be ac coupled