This Portion of Electrical and Electronic Instrumentation contains Signal Conditioning MCQs (Multiple Choice Questions and Answers) / Objective Type Questions and Answers.

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

- Signal Conditioning
- Operational Amplifier
- OPAMPS Circuits Used in instrumentation
- Differential Amplifier
- Instrumentation Amplifier
- Attenuators
- Amplitude modulation
- Amplitude Demodulation
- Filters
- LC Filters
- Active Filters
- Wheatstone Bridges
- A.C Bridges
- Analog/Digital/Analog Conversion Techniques
- Integration and differentiation Using R.C Circuits
- Clipping Circuits

#### 1. Excitation and amplification systems are needed for :

- For active transducers only
- For passive transducers only
- For both active and passive transducers
- For both passive and output transducers

D. For both passive and output transducers

#### 2. A d.c amplifier

- Needs to have a balanced differential inputs with a high common mode rejection ratio(CMRR) to give very good thermal and long term stability
- Easy to calibrate at low frequencies and has ability to recover from overload conditions
- Is prove to drift and low frequency spurious signals come out as data information
- Is followed by a low pass filter to eliminate high frequency components including noise from the data signal
- All the above

E. All the above

#### 3. When using a.c signal conditioning system for capacitive transducers , the carrier frequencies,

- Range between 50 Hz an 20 kHz
- Should be of the order of 0.5 MHz
- Should be of the order of 20MHz
- None of the above.

B. Should be of the order of 0.5 MHz

#### 4. An a.c signal conditioning system is normally used for

- Resistive transducers like strain gauges
- Inductive and capacitive transducers
- Piezoelectric transducers
- All of the above.

B. Inductive and capacitive transducers

#### 5. In a carrier system, drift and spurious signals are important,

- Because they modulate the carrier
- Because they do not modulate the carrier
- Because it is easy to achieve a stable carrier than a stabilized d.c source.
- None of the above.

A. Because they modulate the carrier

#### 6. When using d.c signal conditioning system, with a carrier of 3 kHz, the data frequency should be limited to :

- 1 kHz
- 5 Hz
- 600 Hz
- 2 MHz

C. 600 Hz

#### 7. An operational amplifier has an open loop gain of 200000Ω.its output exhibits saturation at 10 V. the threshold differential voltage of the amplifier is:

- 25 µV
- 50 µV
- 0.5 mV
- 10 V

B. 50 µV

#### 8. An ideal OPAMP has a gain of – 100. The input is connected to inverting end and the input resistance is 1 KΩ. The feedback resistance is ,

- 100 KΩ
- 10 Ω
- 100 Ω
- 1000 KΩ

A. 100 KΩ

#### 9. An ideal OPAMP has a gain of – 100. The input is connected to inverting end and the input resistance is 1 KΩ. The value of feedback resistance is :

- 101 KΩ
- 99 KΩ
- 9.9 KΩ
- 1.01 KΩ

B. 99 KΩ

#### 10. The properties of an ideal OPAMP are,

- It should have zero input impedance
- It should have an infinite output impedance
- It should have a zero open loop gain
- None of the above.

D. None of the above.

#### 11. The closed loop gain of an OPAMP is dependent upon whether the OPAMP is used,

- In inverting mode
- In non-inverting mode
- Is independent of the fact whether the input is connected to inverting or the non-inverting terminal
- Is dependent upon the fact that whether the input is connected to inverting or the non-inverting terminal.

D. Is dependent upon the fact that whether the input is connected to inverting or the non-inverting terminal.

#### 12. The differential (open loop) gain of an OPAMP is 20,000. The input resistance is 2 kΩ and the feedback resistor has a value of 200 kΩ. the closed loop gain of the amplifier is :

- -9.9995
- -9.9955
- -10
- +10

A. -9.9995

#### 13. A buffer amplifier has gain of

- Infinite
- Zero
- Unity
- Depend upon the circuit parameter

C. Unity

#### 14. An operational amplifier has a bandwidth of 100kHz. Negative feedback is introduced with a loop gain of 50. The bandwidth with feedback is

- 2kHz
- 49kHz
- 5.1MHz
- 1.96kHz.

C. 5.1MHz

#### 15. The order of input resistance of 741 OPAMP is,

- 10 Ω to 10
^{3}Ω - 10
^{3}Ω to 10^{6}Ω - 10
^{3}Ω to 10^{9}Ω - 10 ×10
^{3}Ω to 10^{9}Ω

D. 10 ×10

^{3}Ω to 10^{9}Ω#### 16. The order of output resistance of 741 OPAMP is,

- 0.1 Ω to 10 Ω
- 10 Ω to 10
^{5}kΩ - 10 ×10
^{3}Ω to 10^{9}Ω - 10
^{3}Ω to 10^{6}Ω.

B. 10 Ω to 10

^{5}kΩ#### 17. The gain of a 741 OPAMP falls off at a low frequency of,

- 10 kHz
- 10 Hz
- 100 Hz
- 1000 Hz

B. 10 Hz

#### 18. An OPAMP having an open loop gain of A_{vol} is designed with feed factor β where β = R_{1}/(R_{1}+ R_{f} ) is the input resistance connected to non-inverting end and R is the resistance in the feedback path, the closed loop gain is :

- -R
_{f}/R_{1}[ 1/(1+(1/A_{vol}β))] - R
_{f}/R_{1}[ 1/(1+(1 + A_{vol}β))] - R
_{f}/R_{1}[ 1/(1+(1 - A_{vol}β))] - -R
_{f}/R_{1}[ 1/(1+(1 + A_{vol}β))]

A. -R

_{f}/R_{1}[ 1/(1+(1/A_{vol}β))]#### 19. An OPAMP having an open loop gain is designed with a loop gain (A_{vol} β) where β = R_{1}/(R_{1}+ R_{f} ) with R_{1} = resistance connected to non-inverting end and R_{f} = resistance connected in the feedback path, the input resistance of the amplifier (R_{inf}) with feedback is :

- R
_{inf}= R_{in}(1+ A_{vol}β) - R
_{inf}= R_{in}(1- A_{vol}β) - R
_{inf}= R_{in}(1+β) - R
_{inf}= R_{in}(1- β)

A. R

_{inf}= R_{in}(1+ A_{vol}β)#### 20. An OPAMP having an open loop gain is designed with a loop gain (A_{vol} β) where β = R_{1}/(R_{1}+ R_{f} ) with R_{1} = resistance connected to non-inverting end and R_{f} = resistance connected in the feedback path, the output resistance of the amplifier (R_{of}) with feedback is :

- R
_{of}= R_{0}/(1- A_{vol}β) - R
_{of}= R_{0}/(1- β) - R
_{of}= R_{0}/(1+ β) - R
_{of}= R_{0}/(1+ A_{vol}β)

D. R

_{of}= R_{0}/(1+ A_{vol}β)#### 21. Offset voltages in OPAMP are produced because of :

- Variations in the input voltage applied to the amplifier
- Mismatch between the two differential amplifiers which form the IC of the OPAMP chip
- Mismatch between the input signals applied to the OPAMP
- None of the above.

B. Mismatch between the two differential amplifiers which form the IC of the OPAMP chip

#### 22. The typical value of input offset voltage of a 741 OPAMP is :

- 2 µV
- 12 mV
- 2 V
- 0.2 V

B. 12 mV

#### 23. The typical value of input offset Current of a 741 OPAMP is :

- 10 nA
- 10 mA
- 10 pA
- 100 mA

A. 10 nA