ECE-EX2

• Which parameter measures an amplifier's ability to reject common mode signal?

  
  

  CMRR
• LDR (Light Dependent Resistor)


  • Sensitive device that varies its resistance when exposed to light
  • Resistance decreases when incident light decreases
• Potentiometer


  Provides a variable reference voltage, through voltage divider, for comparator
• What term describes a noise signal spread out equally across the frequency spectrum?

  white noise
• What term describes an arrangement of circuits in which the output of one circuit becomes the input to the next?

  CASCADED/MULTISTAGE
• What term describes the maximum rate of change of the output voltage in response to a step input voltage of an Op-amp?

  SLEW RATE
• What characteristic of certain types of electronic circuits specifies the usable range of frequencies that pass from input to output?

  Filter Bandwidth
• What process involves returning a portion of the output signal to the input of an amplifier such that it is out of phase with the input signal?

  Negative Feedback
• What type of filter blocks or rejects a range of frequencies lying between a certain lower frequency and a certain higher frequency?

  Band-stop filter
• What term describes the rate of decrease in gain below or above the critical frequencies of a filter

  Roll off rate
• It is the ratio of the center frequency to the bandwidth of a band-pass filter.

  Quality factor
• A filter frequency response that provides a very flat amplitude response in the passband and a roll-off rate of -20dB/decade/pole.

  Butterworth Response
• If the feedback resistor in an inverting amplifier opens, the gain becomes zero.

  True of False?

  • False
• The band frequencies define a level where the gain or quantity of interest will be 70.7% or its maximum value.

  True or False?

  • True
• A low-pass filter can pass a dc voltage.

  True or False?

  • True
• 9. The higher the Q, the wider the bandwidth of a band-pass filter.

  True or False?

  • False
• A single-pole filter has one RC circuit.

  True or False?

  • True
• The gain of a voltage-follower is very high.

  True or False?

  • False
• The loop gain of an ideal Op-Amp is infinite.

  True or False?

  • True
• The input impedance of an ideal Op-Amp is infinite.

  True or False?

  • True
• Common-mode operation involves the use of the same polarity inputs.

  True or False?

  • True
• Control System


  A combination of various elements connected as a unit to direct or regulate itself or any other system in order to provide a specific output
• Control System


  • Is used to direct the functioning of a physical system to carry out the desired objective
• Types of Control Loop System

  • Open Loop Control System
  • Closed-Loop Control System
• Open-loop Control System

  The applied input or the controlling factor is independent of the system output
• Open-loop control system


  Non-feedback system, no comparison is done between input and output of the system for controlling actions
• Advantages of Open-loop Control System

  • Simplicity in construction and ease of maintenance
  • Lesser number of units, overall the system is economic
  • The output provided by the system shows stability
  • The operation is quite convenient
• Disadvantages of Open-loop Control System

  • Require timely recalibration
  • More prone to errors
  • Changes in the desired output can be the result of internal or external disturbances
• Closed-Loop Control System


  The applied input or controlling factor depends on the output of the system
• Closed-Loop Control System


  Feedback control system, comparison between input and achieved output is done to get the desired output signal
• Closed-Loop Control System


  • Sensitivity: Ability to show instant variation in output whenever there exists any change in input
  • Stability: The system must be stable while providing the output without showing fluctuation with time
  • Bandwidth: The permissible frequency range of the system specifies its bandwidth. And so to have a good frequency response the system must possess high bandwidth
• Closed-Loop Control System

  • Noise: Unwanted signals that hinders the performance of the system adversely is known as noise. A good control system must show the least susceptibility towards the noise
  • Accuracy: The system must produce accurate output, so as to have least chances of error in the achieved output value
  • Speed: Speed defines the processing time of the system within which the specified output is achieved. So the speed of the system must be high enough to deliver the output timely
• Closed-Loop Control System


  Fully automatic control system, the achieved output is automatically compared with the reference input to have the required output
• Types of Feedback

  • Positive Feedback: The input signal and the feedback signal are in phase with each other
  • Negative Feedback: The input signal and the feedback signal show out-of-phase relationship with each other
• Feedback System

  All or part of the output signal either positive or negative is fed back to the input
• Feedback System


  Used to provide more corrective response, by comparing the achieved output with the applied input
• Feedback System


  By the use of feedback in a control system, the system shows less sensitivity to the unwanted internal and external disturbances
• Positive Feedback system
• Negative Feedback system


  The feedback signal is out of phase with the reference input, the two signals are subtracted to produce the difference signal
• Feedback Amplifier

  A device that is based on the principle of feedback, where some part or fraction of output is combined with the input